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How to have a collapsing of top view into a smaller sized view?

This question was asked before in a too broad and unclear way here, so I've made it much more specific, with full explanation and code of what I've tried.
Background
I'm required to mimic the way the Google Calendar has a view at the top, that can animate and push down the view at the bottom, yet it has extra, different behavior. I've summarized what I'm trying to do on 3 characteristics:
Pressing on the toolbar will always work, to toggle expanding/collapsing of the top view, while having an arrow icon that changes its rotation. This is like on Google Calendar app.
The top view will always snap, just like on Google Calendar app.
When the top view is collapsed, only pressing on the toolbar will allow to expand it. This is like on Google Calendar app
When the top view is expanded, scrolling at the bottom view will only allow to collapse. If you try to scroll the other direction, nothing occurs, not even to the bottom view. This is like on Google Calendar app
Once collapsed, the top view will be replaced with a smaller view. This means it will always take some space, above the bottom view. This is not like on Google Calendar app, because on the Calendar app, the top view completely disappears once you collapse it.
Here's how Google Calendar app look like:
Scrolling on the bottom view also slowly hides the view at the top:
The problem
Using various solutions I've found in the past, I've succeeded to implement only a part of the needed behavior:
Having some UI in the toolbar is done by having some views in it, including the arrow view. For manual expanding/collapsing I use setExpanded on the AppBarLayout view. For the rotation of the arrow, I use a listener of how much the AppBarLayout has resized, using addOnOffsetChangedListener on it.
Snapping is easily done by adding snap value into layout_scrollFlags attribute of the CollapsingToolbarLayout. However, to make it really work well, without weird issues (reported here), I used this solution.
Blocking of affecting the top view when scrolling can be done by using the same code I've used on #2 (here), by calling setExpandEnabled there.
This works fine for when the top view is collapsed.
Similar to #3, but sadly, since it uses setNestedScrollingEnabled, which is in both directions, this works well only when the top view is collapsed. When it's expanded, it still allows the bottom view to scroll up, as opposed to Calendar app. When expanded, I need it to only allow to collapse, without allowing to really scroll.
Here's a demonstration of the good, and the bad:
This I've failed completely to do. I've tried a lot of solutions I've thought about, putting views in various places with various flags.
In short, I've succeeded doing 1-3, but not 4-5.
The code
Here's the current code (also available as whole project here) :
ScrollingActivity.kt
class ScrollingActivity : AppCompatActivity(), AppBarTracking {
private var mNestedView: MyRecyclerView? = null
private var mAppBarOffset: Int = 0
private var mAppBarIdle = false
private var mAppBarMaxOffset: Int = 0
private var isExpanded: Boolean = false
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_scrolling)
val toolbar = findViewById<Toolbar>(R.id.toolbar)
setSupportActionBar(toolbar)
mNestedView = findViewById(R.id.nestedView)
app_bar.addOnOffsetChangedListener({ appBarLayout, verticalOffset ->
mAppBarOffset = verticalOffset
val totalScrollRange = appBarLayout.totalScrollRange
val progress = (-verticalOffset).toFloat() / totalScrollRange
arrowImageView.rotation = 180 + progress * 180
isExpanded = verticalOffset == 0;
mAppBarIdle = mAppBarOffset >= 0 || mAppBarOffset <= mAppBarMaxOffset
if (mAppBarIdle)
setExpandAndCollapseEnabled(isExpanded)
})
app_bar.post(Runnable { mAppBarMaxOffset = -app_bar.totalScrollRange })
mNestedView!!.setAppBarTracking(this)
mNestedView!!.layoutManager = LinearLayoutManager(this)
mNestedView!!.adapter = object : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
override fun getItemCount(): Int = 100
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return object : ViewHolder(LayoutInflater.from(parent.context).inflate(android.R.layout.simple_list_item_1, parent, false)) {}
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
(holder.itemView.findViewById<View>(android.R.id.text1) as TextView).text = "item $position"
}
}
expandCollapseButton.setOnClickListener({ v ->
isExpanded = !isExpanded
app_bar.setExpanded(isExpanded, true)
})
}
private fun setExpandAndCollapseEnabled(enabled: Boolean) {
mNestedView!!.isNestedScrollingEnabled = enabled
}
override fun isAppBarExpanded(): Boolean = mAppBarOffset == 0
override fun isAppBarIdle(): Boolean = mAppBarIdle
}
MyRecyclerView.kt
/**A RecyclerView that allows temporary pausing of casuing its scroll to affect appBarLayout, based on https://stackoverflow.com/a/45338791/878126 */
class MyRecyclerView #JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyle: Int = 0) : RecyclerView(context, attrs, defStyle) {
private var mAppBarTracking: AppBarTracking? = null
private var mView: View? = null
private var mTopPos: Int = 0
private var mLayoutManager: LinearLayoutManager? = null
interface AppBarTracking {
fun isAppBarIdle(): Boolean
fun isAppBarExpanded(): Boolean
}
override fun dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?,
type: Int): Boolean {
if (type == ViewCompat.TYPE_NON_TOUCH && mAppBarTracking!!.isAppBarIdle()
&& isNestedScrollingEnabled) {
if (dy > 0) {
if (mAppBarTracking!!.isAppBarExpanded()) {
consumed!![1] = dy
return true
}
} else {
mTopPos = mLayoutManager!!.findFirstVisibleItemPosition()
if (mTopPos == 0) {
mView = mLayoutManager!!.findViewByPosition(mTopPos)
if (-mView!!.top + dy <= 0) {
consumed!![1] = dy - mView!!.top
return true
}
}
}
}
val returnValue = super.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow, type)
if (offsetInWindow != null && !isNestedScrollingEnabled && offsetInWindow[1] != 0)
offsetInWindow[1] = 0
return returnValue
}
override fun setLayoutManager(layout: RecyclerView.LayoutManager) {
super.setLayoutManager(layout)
mLayoutManager = layoutManager as LinearLayoutManager
}
fun setAppBarTracking(appBarTracking: AppBarTracking) {
mAppBarTracking = appBarTracking
}
}
ScrollingCalendarBehavior.kt
class ScrollingCalendarBehavior(context: Context, attrs: AttributeSet) : AppBarLayout.Behavior(context, attrs) {
override fun onInterceptTouchEvent(parent: CoordinatorLayout?, child: AppBarLayout?, ev: MotionEvent): Boolean = false
}
activity_scrolling.xml
<android.support.design.widget.CoordinatorLayout
android:id="#+id/coordinatorLayout" xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".ScrollingActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar" android:layout_width="match_parent" android:layout_height="wrap_content"
android:fitsSystemWindows="true" android:stateListAnimator="#null" android:theme="#style/AppTheme.AppBarOverlay"
app:expanded="false" app:layout_behavior="com.example.user.expandingtopviewtest.ScrollingCalendarBehavior"
tools:targetApi="lollipop">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsingToolbarLayout" android:layout_width="match_parent"
android:layout_height="match_parent" android:fitsSystemWindows="true"
android:minHeight="?attr/actionBarSize" app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed|snap" app:statusBarScrim="?attr/colorPrimaryDark">
<LinearLayout
android:layout_width="match_parent" android:layout_height="250dp"
android:layout_marginTop="?attr/actionBarSize" app:layout_collapseMode="parallax"
app:layout_collapseParallaxMultiplier="1.0">
<TextView
android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="10dp"
android:paddingRight="10dp" android:text="some large, expanded view"/>
</LinearLayout>
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar" android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize" app:layout_collapseMode="pin"
app:popupTheme="#style/AppTheme.PopupOverlay">
<android.support.constraint.ConstraintLayout
android:id="#+id/expandCollapseButton" android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize" android:background="?android:selectableItemBackground"
android:clickable="true" android:focusable="true" android:orientation="vertical">
<TextView
android:id="#+id/titleTextView" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:layout_marginBottom="8dp"
android:layout_marginLeft="8dp" android:layout_marginStart="8dp" android:ellipsize="end"
android:gravity="center" android:maxLines="1" android:text="title"
android:textAppearance="#style/TextAppearance.Widget.AppCompat.Toolbar.Title"
android:textColor="#android:color/white" app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"/>
<ImageView
android:id="#+id/arrowImageView" android:layout_width="wrap_content" android:layout_height="0dp"
android:layout_marginLeft="8dp" android:layout_marginStart="8dp"
app:layout_constraintBottom_toBottomOf="#+id/titleTextView"
app:layout_constraintStart_toEndOf="#+id/titleTextView"
app:layout_constraintTop_toTopOf="#+id/titleTextView"
app:srcCompat="#android:drawable/arrow_down_float"
tools:ignore="ContentDescription,RtlHardcoded"/>
</android.support.constraint.ConstraintLayout>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<com.example.user.expandingtopviewtest.MyRecyclerView
android:id="#+id/nestedView" android:layout_width="match_parent" android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" tools:context=".ScrollingActivity"/>
</android.support.design.widget.CoordinatorLayout>
The questions
How can I make the scrolling being blocked when the top view is expanded, yet allow to collapse while scrolling ?
How can I make the top view be replaced with a smaller one when collapsed (and back to large one when expanded), instead of completely disappear ?
Update
Even though I've got the basic of what I asked about, there are still 2 issues with the current code (available on Github, here) :
The small view (the one you see on collapsed state) has inner views that need to have a clicking effect on them. When using the android:background="?attr/selectableItemBackgroundBorderless" on them, and clicking on this area while being expanded, the clicking is done on the small view. I've handled it by putting the small view on a different toolbar, but then the clicking effect doesn't get shown at all. I've written about this here, including sample project.
Here's the fix:
<android.support.design.widget.CoordinatorLayout
android:id="#+id/coordinatorLayout" xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar" android:layout_width="match_parent" android:layout_height="wrap_content"
android:fitsSystemWindows="true" android:stateListAnimator="#null" android:theme="#style/AppTheme.AppBarOverlay"
app:expanded="false" app:layout_behavior="com.example.expandedtopviewtestupdate.ScrollingCalendarBehavior"
tools:targetApi="lollipop">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsingToolbarLayout" android:layout_width="match_parent"
android:layout_height="match_parent" android:clipChildren="false" android:clipToPadding="false"
android:fitsSystemWindows="true" app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed|snap|enterAlways"
app:statusBarScrim="?attr/colorPrimaryDark">
<!--large view -->
<LinearLayout
android:id="#+id/largeView" android:layout_width="match_parent" android:layout_height="280dp"
android:layout_marginTop="?attr/actionBarSize" android:orientation="vertical"
app:layout_collapseMode="parallax" app:layout_collapseParallaxMultiplier="1.0">
<TextView
android:id="#+id/largeTextView" android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_gravity="center"
android:background="?attr/selectableItemBackgroundBorderless" android:clickable="true"
android:focusable="true" android:focusableInTouchMode="false" android:gravity="center"
android:text="largeView" android:textSize="14dp" tools:background="?attr/colorPrimary"
tools:layout_gravity="top|center_horizontal" tools:layout_height="40dp" tools:layout_width="40dp"
tools:text="1"/>
</LinearLayout>
<!--top toolbar-->
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar" android:layout_width="match_parent" android:layout_height="wrap_content"
android:layout_marginBottom="#dimen/small_view_height" app:contentInsetStart="0dp"
app:layout_collapseMode="pin" app:popupTheme="#style/AppTheme.PopupOverlay">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent" android:layout_height="wrap_content" android:clickable="true"
android:focusable="true">
<LinearLayout
android:id="#+id/expandCollapseButton" android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?android:selectableItemBackground" android:gravity="center_vertical"
android:orientation="horizontal" app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:id="#+id/titleTextView" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:ellipsize="end" android:gravity="center"
android:maxLines="1" android:text="title"
android:textAppearance="#style/TextAppearance.Widget.AppCompat.Toolbar.Title"
android:textColor="#android:color/white"/>
<ImageView
android:id="#+id/arrowImageView" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:layout_marginLeft="8dp"
android:layout_marginStart="8dp" app:srcCompat="#android:drawable/arrow_up_float"
tools:ignore="ContentDescription,RtlHardcoded"/>
</LinearLayout>
</android.support.constraint.ConstraintLayout>
</android.support.v7.widget.Toolbar>
<android.support.v7.widget.Toolbar
android:id="#+id/smallLayoutContainer" android:layout_width="match_parent"
android:layout_height="wrap_content" android:layout_marginTop="?attr/actionBarSize"
android:clipChildren="false" android:clipToPadding="false" app:contentInsetStart="0dp"
app:layout_collapseMode="pin">
<!--small view-->
<LinearLayout
android:id="#+id/smallLayout" android:layout_width="match_parent"
android:layout_height="#dimen/small_view_height" android:clipChildren="false"
android:clipToPadding="false" android:orientation="horizontal" tools:background="#ff330000"
tools:layout_height="#dimen/small_view_height">
<TextView
android:id="#+id/smallTextView" android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_gravity="center"
android:background="?attr/selectableItemBackgroundBorderless" android:clickable="true"
android:focusable="true" android:focusableInTouchMode="false" android:gravity="center"
android:text="smallView" android:textSize="14dp" tools:background="?attr/colorPrimary"
tools:layout_gravity="top|center_horizontal" tools:layout_height="40dp"
tools:layout_width="40dp" tools:text="1"/>
</LinearLayout>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<com.example.expandedtopviewtestupdate.MyRecyclerView
android:id="#+id/nestedView" android:layout_width="match_parent" android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" tools:context=".ScrollingActivity"/>
</android.support.design.widget.CoordinatorLayout>
The Google Calendar allows to perform a scroll-down gesture on the toolbar itself, to trigger showing the month view. I've succeeded only adding a clicking event there, but not scrolling. Here's how it looks like:

Note: Full updated project is available here.
How can I make the scrolling being blocked when the top view is expanded, yet allow to collapse while scrolling ?
Issue #1: The RecyclerView should not be able to scroll at all when the app bar is not collapsed. To fix this, add enterAlways to the scroll flags for the CollapsingToolbarLayout as follows:
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsingToolbarLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipChildren="false"
android:clipToPadding="false"
android:fitsSystemWindows="true"
app:layout_scrollFlags="scroll|exitUntilCollapsed|snap|enterAlways"
app:statusBarScrim="?attr/colorPrimaryDark">
enterAlways will not cause the app bar to open when closed since you are suppressing that functionality but works as desired otherwise.
Issue #2: When the app bar is fully expanded, the RecyclerView should not be allowed to scroll up. This happens to be a distinct issue from issue #1.
[Updated] To correct this, modify the behavior for the RecyclerView to consume scroll when the RecyclerView tries to scroll up and the app bar is fully expanded or will be fully expanded after the scroll(dy) is consumed . The RecyclerView can scroll up, but it never sees that action since its behavior, SlidingPanelBehavior, consumes the scroll. If the app bar is not fully expanded but will be expanded after the current scroll is consumed, the behavior forces the app bar to fully expand by calling modifying dy and calling the super before fully consuming the scroll. (See SlidingPanelBehavior#onNestedPreScroll()). (In the previous answer, the appBar behavior was modified. Putting the behavior change on RecyclerView is a better choice.)
Issue #3: Setting nested scrolling for the RecyclerView to enable/disabled when nested scrolling is already in the required state causes problems. To avoid these issues, only change the state of nested scrolling when a change is really being made with the following code change in ScrollingActivity:
private void setExpandAndCollapseEnabled(boolean enabled) {
if (mNestedView.isNestedScrollingEnabled() != enabled) {
mNestedView.setNestedScrollingEnabled(enabled);
}
}
This is how the test app behaves with the changes from above:
The changed modules with the above-mentioned changes are at the end of the post.
How can I make the top view be replaced with a smaller one when collapsed (and back to large one when expanded), instead of completely disappear ?
[Update] Make the smaller view a direct child of CollapsingToolbarLayout so it is a sibling of Toolbar. The following is a demonstration of this approach. The collapseMode of the smaller view is set to pin. The smaller view's margins as well as the margins of the toolbar are adjusted so the smaller view falls immediately below the toolbar. Since CollapsingToolbarLayout is a FrameLayout, views stack and the height of the FrameLayout just becomes the height of the tallest child view. This structure will avoid the issue where the insets needed adjustment and the problem with the missing click effect.
One final issue remains and that dragging the appbar down should open it with the assumption that dragging the smaller view down should not open the appbar. Permitting the appbar to open upon dragging is accomplished with setDragCallback of AppBarLayout.Behavior. Since the smaller view is incorporated into the appBar, dragging it down will open the appbar. To prevent this, a new behavior called MyAppBarBehavior is attached to the appbar. This behavior, in conjunction with code in the MainActivity prevents dragging of the smaller view to open the appbar but will permit the toolbar to be dragged.
activity_main.xml
<android.support.design.widget.CoordinatorLayout
android:id="#+id/coordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
android:stateListAnimator="#null"
android:theme="#style/AppTheme.AppBarOverlay"
app:expanded="false"
app:layout_behavior=".MyAppBarBehavior"
tools:targetApi="lollipop">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsingToolbarLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipChildren="false"
android:clipToPadding="false"
android:fitsSystemWindows="true"
app:layout_scrollFlags="scroll|exitUntilCollapsed|snap|enterAlways"
app:statusBarScrim="?attr/colorPrimaryDark">
<!--large view -->
<LinearLayout
android:id="#+id/largeView"
android:layout_width="match_parent"
android:layout_height="280dp"
android:layout_marginTop="?attr/actionBarSize"
android:orientation="vertical"
app:layout_collapseMode="parallax"
app:layout_collapseParallaxMultiplier="1.0">
<TextView
android:id="#+id/largeTextView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:background="?attr/selectableItemBackgroundBorderless"
android:clickable="true"
android:focusable="true"
android:focusableInTouchMode="false"
android:gravity="center"
android:text="largeView"
android:textSize="14dp"
tools:background="?attr/colorPrimary"
tools:layout_gravity="top|center_horizontal"
tools:layout_height="40dp"
tools:layout_width="40dp"
tools:text="1" />
</LinearLayout>
<!--top toolbar-->
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="#dimen/small_view_height"
app:contentInsetStart="0dp"
app:layout_collapseMode="pin"
app:popupTheme="#style/AppTheme.PopupOverlay">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clickable="true"
android:focusable="true">
<LinearLayout
android:id="#+id/expandCollapseButton"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?android:selectableItemBackground"
android:gravity="center_vertical"
android:orientation="horizontal"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:id="#+id/titleTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ellipsize="end"
android:gravity="center"
android:maxLines="1"
android:text="title"
android:textAppearance="#style/TextAppearance.Widget.AppCompat.Toolbar.Title"
android:textColor="#android:color/white" />
<ImageView
android:id="#+id/arrowImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="8dp"
android:layout_marginStart="8dp"
app:srcCompat="#android:drawable/arrow_up_float"
tools:ignore="ContentDescription,RtlHardcoded" />
</LinearLayout>
</android.support.constraint.ConstraintLayout>
</android.support.v7.widget.Toolbar>
<!--small view-->
<LinearLayout
android:id="#+id/smallLayout"
android:layout_width="match_parent"
android:layout_height="#dimen/small_view_height"
android:layout_marginTop="?attr/actionBarSize"
android:clipChildren="false"
android:clipToPadding="false"
android:orientation="horizontal"
app:layout_collapseMode="pin"
tools:background="#ff330000"
tools:layout_height="#dimen/small_view_height">
<TextView
android:id="#+id/smallTextView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:background="?attr/selectableItemBackgroundBorderless"
android:clickable="true"
android:focusable="true"
android:focusableInTouchMode="false"
android:gravity="center"
android:text="smallView"
android:textSize="14dp"
tools:background="?attr/colorPrimary"
tools:layout_gravity="top|center_horizontal"
tools:layout_height="40dp"
tools:layout_width="40dp"
tools:text="1" />
</LinearLayout>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<com.example.expandedtopviewtestupdate.MyRecyclerView
android:id="#+id/nestedView"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".SlidingPanelBehavior" />
</android.support.design.widget.CoordinatorLayout>
Finally, in the addOnOffsetChangedListener add the following code to fade out/fade in the smaller view as the app bar expands and contracts. Once the view's alpha is zero (invisible), set its visibility to View.INVISIBLE so it can't be clicked. Once the view's alpha increases above zero, make it visible and clickable by setting its visibility to View.VISIBLE.
mSmallLayout.setAlpha((float) -verticalOffset / totalScrollRange);
// If the small layout is not visible, make it officially invisible so
// it can't receive clicks.
if (alpha == 0) {
mSmallLayout.setVisibility(View.INVISIBLE);
} else if (mSmallLayout.getVisibility() == View.INVISIBLE) {
mSmallLayout.setVisibility(View.VISIBLE);
}
Here are the results:
Here are the new modules with all of the above changes incorporated.
MainActivity.java
public class MainActivity extends AppCompatActivity
implements MyRecyclerView.AppBarTracking {
private MyRecyclerView mNestedView;
private int mAppBarOffset = 0;
private boolean mAppBarIdle = true;
private int mAppBarMaxOffset = 0;
private AppBarLayout mAppBar;
private boolean mIsExpanded = false;
private ImageView mArrowImageView;
private LinearLayout mSmallLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
LinearLayout expandCollapse;
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
expandCollapse = findViewById(R.id.expandCollapseButton);
mArrowImageView = findViewById(R.id.arrowImageView);
mNestedView = findViewById(R.id.nestedView);
mAppBar = findViewById(R.id.app_bar);
mSmallLayout = findViewById(R.id.smallLayout);
// Log when the small text view is clicked
findViewById(R.id.smallTextView).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.d(TAG, "<<<<click small layout");
}
});
// Log when the big text view is clicked.
findViewById(R.id.largeTextView).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.d(TAG, "<<<<click big view");
}
});
setSupportActionBar(toolbar);
ActionBar ab = getSupportActionBar();
if (ab != null) {
getSupportActionBar().setDisplayShowTitleEnabled(false);
}
mAppBar.post(new Runnable() {
#Override
public void run() {
mAppBarMaxOffset = -mAppBar.getTotalScrollRange();
CoordinatorLayout.LayoutParams lp =
(CoordinatorLayout.LayoutParams) mAppBar.getLayoutParams();
MyAppBarBehavior behavior = (MyAppBarBehavior) lp.getBehavior();
// Only allow drag-to-open if the drag touch is on the toolbar.
// Once open, all drags are allowed.
if (behavior != null) {
behavior.setCanOpenBottom(findViewById(R.id.toolbar).getHeight());
}
}
});
mNestedView.setAppBarTracking(this);
mNestedView.setLayoutManager(new LinearLayoutManager(this));
mNestedView.setAdapter(new RecyclerView.Adapter<RecyclerView.ViewHolder>() {
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new ViewHolder(
LayoutInflater.from(parent.getContext())
.inflate(android.R.layout.simple_list_item_1, parent, false));
}
#SuppressLint("SetTextI18n")
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
((TextView) holder.itemView.findViewById(android.R.id.text1))
.setText("Item " + position);
}
#Override
public int getItemCount() {
return 200;
}
class ViewHolder extends RecyclerView.ViewHolder {
public ViewHolder(View view) {
super(view);
}
}
});
mAppBar.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
#Override
public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
mAppBarOffset = verticalOffset;
int totalScrollRange = appBarLayout.getTotalScrollRange();
float progress = (float) (-verticalOffset) / (float) totalScrollRange;
mArrowImageView.setRotation(-progress * 180);
mIsExpanded = verticalOffset == 0;
mAppBarIdle = mAppBarOffset >= 0 || mAppBarOffset <= mAppBarMaxOffset;
float alpha = (float) -verticalOffset / totalScrollRange;
mSmallLayout.setAlpha(alpha);
// If the small layout is not visible, make it officially invisible so
// it can't receive clicks.
if (alpha == 0) {
mSmallLayout.setVisibility(View.INVISIBLE);
} else if (mSmallLayout.getVisibility() == View.INVISIBLE) {
mSmallLayout.setVisibility(View.VISIBLE);
}
}
});
expandCollapse.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
setExpandAndCollapseEnabled(true);
if (mIsExpanded) {
setExpandAndCollapseEnabled(false);
}
mIsExpanded = !mIsExpanded;
mNestedView.stopScroll();
mAppBar.setExpanded(mIsExpanded, true);
}
});
}
private void setExpandAndCollapseEnabled(boolean enabled) {
if (mNestedView.isNestedScrollingEnabled() != enabled) {
mNestedView.setNestedScrollingEnabled(enabled);
}
}
#Override
public boolean isAppBarExpanded() {
return mAppBarOffset == 0;
}
#Override
public boolean isAppBarIdle() {
return mAppBarIdle;
}
private static final String TAG = "MainActivity";
}
SlidingPanelBehavior.java
public class SlidingPanelBehavior extends AppBarLayout.ScrollingViewBehavior {
private AppBarLayout mAppBar;
public SlidingPanelBehavior() {
super();
}
public SlidingPanelBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean layoutDependsOn(final CoordinatorLayout parent, View child, View dependency) {
if (mAppBar == null && dependency instanceof AppBarLayout) {
// Capture our appbar for later use.
mAppBar = (AppBarLayout) dependency;
}
return dependency instanceof AppBarLayout;
}
#Override
public boolean onInterceptTouchEvent(CoordinatorLayout parent, View child, MotionEvent event) {
int action = event.getAction();
if (event.getAction() != MotionEvent.ACTION_DOWN) { // Only want "down" events
return false;
}
if (getAppBarLayoutOffset(mAppBar) == -mAppBar.getTotalScrollRange()) {
// When appbar is collapsed, don't let it open through nested scrolling.
setNestedScrollingEnabledWithTest((NestedScrollingChild2) child, false);
} else {
// Appbar is partially to fully expanded. Set nested scrolling enabled to activate
// the methods within this behavior.
setNestedScrollingEnabledWithTest((NestedScrollingChild2) child, true);
}
return false;
}
#Override
public boolean onStartNestedScroll(#NonNull CoordinatorLayout coordinatorLayout, #NonNull View child,
#NonNull View directTargetChild, #NonNull View target,
int axes, int type) {
//noinspection RedundantCast
return ((NestedScrollingChild2) child).isNestedScrollingEnabled();
}
#Override
public void onNestedPreScroll(#NonNull CoordinatorLayout coordinatorLayout, #NonNull View child,
#NonNull View target, int dx, int dy, #NonNull int[] consumed,
int type) {
// How many pixels we must scroll to fully expand the appbar. This value is <= 0.
final int appBarOffset = getAppBarLayoutOffset(mAppBar);
// Check to see if this scroll will expand the appbar 100% or collapse it fully.
if (dy <= appBarOffset) {
// Scroll by the amount that will fully expand the appbar and dispose of the rest (dy).
super.onNestedPreScroll(coordinatorLayout, mAppBar, target, dx,
appBarOffset, consumed, type);
consumed[1] += dy;
} else if (dy >= (mAppBar.getTotalScrollRange() + appBarOffset)) {
// This scroll will collapse the appbar. Collapse it and dispose of the rest.
super.onNestedPreScroll(coordinatorLayout, mAppBar, target, dx,
mAppBar.getTotalScrollRange() + appBarOffset,
consumed, type);
consumed[1] += dy;
} else {
// This scroll will leave the appbar partially open. Just do normal stuff.
super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
}
}
/**
* {#code onNestedPreFling()} is overriden to address a nested scrolling defect that was
* introduced in API 26. This method prevent the appbar from misbehaving when scrolled/flung.
* <p>
* Refer to "Bug in design support library"
*/
#Override
public boolean onNestedPreFling(#NonNull CoordinatorLayout coordinatorLayout,
#NonNull View child, #NonNull View target,
float velocityX, float velocityY) {
//noinspection RedundantCast
if (((NestedScrollingChild2) child).isNestedScrollingEnabled()) {
// Just stop the nested fling and let the appbar settle into place.
((NestedScrollingChild2) child).stopNestedScroll(ViewCompat.TYPE_NON_TOUCH);
return true;
}
return super.onNestedPreFling(coordinatorLayout, child, target, velocityX, velocityY);
}
private static int getAppBarLayoutOffset(AppBarLayout appBar) {
final CoordinatorLayout.Behavior behavior =
((CoordinatorLayout.LayoutParams) appBar.getLayoutParams()).getBehavior();
if (behavior instanceof AppBarLayout.Behavior) {
return ((AppBarLayout.Behavior) behavior).getTopAndBottomOffset();
}
return 0;
}
// Something goes amiss when the flag it set to its current value, so only call
// setNestedScrollingEnabled() if it will result in a change.
private void setNestedScrollingEnabledWithTest(NestedScrollingChild2 child, boolean enabled) {
if (child.isNestedScrollingEnabled() != enabled) {
child.setNestedScrollingEnabled(enabled);
}
}
#SuppressWarnings("unused")
private static final String TAG = "SlidingPanelBehavior";
}
MyRecyclerView.kt
/**A RecyclerView that allows temporary pausing of casuing its scroll to affect appBarLayout, based on https://stackoverflow.com/a/45338791/878126 */
class MyRecyclerView #JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyle: Int = 0) : RecyclerView(context, attrs, defStyle) {
private var mAppBarTracking: AppBarTracking? = null
private var mView: View? = null
private var mTopPos: Int = 0
private var mLayoutManager: LinearLayoutManager? = null
interface AppBarTracking {
fun isAppBarIdle(): Boolean
fun isAppBarExpanded(): Boolean
}
override fun dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?, type: Int): Boolean {
if (type == ViewCompat.TYPE_NON_TOUCH && mAppBarTracking!!.isAppBarIdle()
&& isNestedScrollingEnabled) {
if (dy > 0) {
if (mAppBarTracking!!.isAppBarExpanded()) {
consumed!![1] = dy
return true
}
} else {
mTopPos = mLayoutManager!!.findFirstVisibleItemPosition()
if (mTopPos == 0) {
mView = mLayoutManager!!.findViewByPosition(mTopPos)
if (-mView!!.top + dy <= 0) {
consumed!![1] = dy - mView!!.top
return true
}
}
}
}
if (dy < 0 && type == ViewCompat.TYPE_TOUCH && mAppBarTracking!!.isAppBarExpanded()) {
consumed!![1] = dy
return true
}
val returnValue = super.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow, type)
if (offsetInWindow != null && !isNestedScrollingEnabled && offsetInWindow[1] != 0)
offsetInWindow[1] = 0
return returnValue
}
override fun setLayoutManager(layout: RecyclerView.LayoutManager) {
super.setLayoutManager(layout)
mLayoutManager = layoutManager as LinearLayoutManager
}
fun setAppBarTracking(appBarTracking: AppBarTracking) {
mAppBarTracking = appBarTracking
}
override fun fling(velocityX: Int, velocityY: Int): Boolean {
var velocityY = velocityY
if (!mAppBarTracking!!.isAppBarIdle()) {
val vc = ViewConfiguration.get(context)
velocityY = if (velocityY < 0) -vc.scaledMinimumFlingVelocity
else vc.scaledMinimumFlingVelocity
}
return super.fling(velocityX, velocityY)
}
}
MyAppBarBehavior.java
/**
* Attach this behavior to AppBarLayout to disable the bottom portion of a closed appBar
* so it cannot be touched to open the appBar. This behavior is helpful if there is some
* portion of the appBar that displays when the appBar is closed, but should not open the appBar
* when the appBar is closed.
*/
public class MyAppBarBehavior extends AppBarLayout.Behavior {
// Touch above this y-axis value can open the appBar.
private int mCanOpenBottom;
// Determines if the appBar can be dragged open or not via direct touch on the appBar.
private boolean mCanDrag = true;
#SuppressWarnings("unused")
public MyAppBarBehavior() {
init();
}
#SuppressWarnings("unused")
public MyAppBarBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
private void init() {
setDragCallback(new AppBarLayout.Behavior.DragCallback() {
#Override
public boolean canDrag(#NonNull AppBarLayout appBarLayout) {
return mCanDrag;
}
});
}
#Override
public boolean onInterceptTouchEvent(CoordinatorLayout parent,
AppBarLayout child,
MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
// If appBar is closed. Only allow scrolling in defined area.
if (child.getTop() <= -child.getTotalScrollRange()) {
mCanDrag = event.getY() < mCanOpenBottom;
}
}
return super.onInterceptTouchEvent(parent, child, event);
}
public void setCanOpenBottom(int bottom) {
mCanOpenBottom = bottom;
}
}

Hide/Show bottomNavigationView on Scroll

I have to hide bottom navigation view on up scroll and show on down scroll .how to implement this?
my layout is like this
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_above="#+id/navigation"
android:layout_alignParentTop="true"
android:layout_marginBottom="5dp">
<FrameLayout
android:id="#+id/container1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="?android:attr/windowBackground"
app:layout_scrollFlags="scroll|enterAlways|snap"
app:menu="#menu/dashboard_slider_menu" />
</RelativeLayout>
I have attached screenshot of view. Kindly check it.

UPDATE
Just add one attribute to BottomNavigationView
Material Library AndroidX
<com.google.android.material.bottomnavigation.BottomNavigationView
....
app:layout_behavior="com.google.android.material.behavior.HideBottomViewOnScrollBehavior"/>
Support Library Version 28.0.0 or higher version
<android.support.design.widget.BottomNavigationView
....
app:layout_behavior="#string/hide_bottom_view_on_scroll_behavior"/>
Note:- Your XML should follow the structure of XML given below in old answer.
**OLD ANSWER(Still Works)**
You need a helper class to do this .This solution works like Google Material Design Guideline.
Create a class BottomNavigationViewBehavior
public class BottomNavigationViewBehavior extends CoordinatorLayout.Behavior<BottomNavigationView> {
private int height;
#Override
public boolean onLayoutChild(CoordinatorLayout parent, BottomNavigationView child, int layoutDirection) {
height = child.getHeight();
return super.onLayoutChild(parent, child, layoutDirection);
}
#Override
public boolean onStartNestedScroll(#NonNull CoordinatorLayout coordinatorLayout,
BottomNavigationView child, #NonNull
View directTargetChild, #NonNull View target,
int axes, int type)
{
return axes == ViewCompat.SCROLL_AXIS_VERTICAL;
}
#Override
public void onNestedScroll(#NonNull CoordinatorLayout coordinatorLayout, #NonNull BottomNavigationView child,
#NonNull View target, int dxConsumed, int dyConsumed,
int dxUnconsumed, int dyUnconsumed,
#ViewCompat.NestedScrollType int type)
{
if (dyConsumed > 0) {
slideDown(child);
} else if (dyConsumed < 0) {
slideUp(child);
}
}
private void slideUp(BottomNavigationView child) {
child.clearAnimation();
child.animate().translationY(0).setDuration(200);
}
private void slideDown(BottomNavigationView child) {
child.clearAnimation();
child.animate().translationY(height).setDuration(200);
}
}
For using this behavior you need to use cooradinator layout...
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.kliff.digitaldwarka.activity.MainActivity">
<android.support.design.widget.CoordinatorLayout
android:id="#+id/coordinator_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/myAppBar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:descendantFocusability="beforeDescendants"
android:focusableInTouchMode="true"
android:theme="#style/AppTheme.AppBarOverlay"
app:elevation="0dp">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:contentInsetStart="0dp"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay"/>
</android.support.design.widget.AppBarLayout>
<!---your RecyclerView/Fragment Container Layout-->
<FrameLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/bottom_nav"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:itemBackground="#color/white"
app:menu="#menu/bottom_nav_menu" />
</android.support.design.widget.CoordinatorLayout>
<!---NavigationView-->
</android.support.v4.widget.DrawerLayout>
Add this code to your Activity that contains bottom nav..
mBottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_nav);
CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) mBottomNavigationView.getLayoutParams();
layoutParams.setBehavior(new BottomNavigationViewBehavior());

Try this,
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy > 0 && bottom_navigation.isShown()) {
bottom_navigation.setVisibility(View.GONE);
} else if (dy < 0 ) {
bottom_navigation.setVisibility(View.VISIBLE);
}
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
});
Image while scrolling up :-
Image while scrolling down:

Updated answer after the latest library updates:
Hiding the BottomNavigationView on scrolling is now available with just one flag in the layout! Starting from version 28.0.0-alpha1 or the material/androidX 1.0.0-alpha1.
I updated my project using the latter approach since the version now is a stable release candidate. Update: Use fully released version "1.0.0"!
The new out of the box available behaviour is called HideBottomViewOnScrollBehavior. Set it on the BottomNavigationView as
app:layout_behavior="#string/hide_bottom_view_on_scroll_behavior" as described in the latest docs.
Here is a full example:
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:labelVisibilityMode="selected"
app:layout_behavior="#string/hide_bottom_view_on_scroll_behavior"
android:layout_gravity="bottom"
app:layout_insetEdge="bottom"
app:menu="#menu/navigation" />
As with the hiding of the Toolbar on scrolling, you have to ensure that the content is a class that supports the latest scrolling like RecyclerView and NestedScrollView.
This ensures all is working as shown in the animation on the design specs
PS: labelVisibilityMode is another cool addition you get for free for taking the trouble of updating and that is described in depth in the design specs.

Update your project to Androidx i.e Refactor >> Migrate to androidx (Minimum Android studio version 3.4)
Using the default Bottom Navigation Menu xml file, replace the parent Constraint Layout with Coordinator layout.
Add the line app:layout_behavior="com.google.android.material.behavior.HideBottomViewOnScrollBehavior"
i.e
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".dashboards.Admin_dashboard_main">
<include layout="#layout/toolbar" />
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/main_area"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintTop_toBottomOf="#+id/toolbar"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:layout_margin="0dp"
android:padding="0dp">
<!-- Fragments Container -->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="MainActivity"
tools:showIn="#layout/activity_tenant_dashboard"
android:id="#+id/fragment_container">
</FrameLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
<!-- Bottom Navigation View -->
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="0dp"
android:layout_marginEnd="0dp"
android:background="?android:attr/windowBackground"
android:layout_gravity="bottom"
app:menu="#menu/menu_admin_dashboard_main"
app:layout_behavior="com.google.android.material.behavior.HideBottomViewOnScrollBehavior"
/>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Use this
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
{
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy)
{
if (dy > 0 ||dy<0 && csButtonLay.isShown())
{
bottomBar.setVisibility(View.GONE);
}
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState)
{
if (newState == RecyclerView.SCROLL_STATE_IDLE)
{
bottomBar.setVisibility(View.VISIBLE);
}
super.onScrollStateChanged(recyclerView, newState);
}
});

Just use CoordinatorLayout as a parent container and add the app:layout_behavior
in the child View and set the behavior #string/hide_bottom_view_on_scroll_behavior
this is the solution.
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".Main2Activity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_above="#id/nav_view"
android:layout_height="wrap_content"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" />
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/nav_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_gravity="bottom"
app:layout_behavior="#string/hide_bottom_view_on_scroll_behavior"
android:background="?android:attr/windowBackground"
app:menu="#menu/bottom_nav_menu" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
Happy Coding.

I encountered this issue working with the Recyclerview.
The attribute:
app:layout_behavior="#string/hide_bottom_view_on_scroll_behavior"/>
only partially worked for me, so I had to implement another solution.
I defined the BottomNavigationView inside the MainActivity so I had to set a couple of methods to animate it during the scrolling.
class MainActivity : AppCompatActivity() {
private var animator: ObjectAnimator? = null
.
.
.
fun slideDown() {
nav_view?.let {
if (animator == null && it.translationY == 0f) {
animator = translationObjectY(it, 0f, it.height.toFloat() + it.marginBottom.toFloat()).apply {
doOnEnd {
animator = null
}
}
}
}
}
fun slideUp() {
nav_view?.let {
if (animator == null && it.translationY == it.height.toFloat() + it.marginBottom.toFloat()) {
animator = translationObjectY(it, it.height.toFloat() + it.marginBottom.toFloat(), 0f).apply {
doOnEnd {
animator = null
}
}
}
}
}
}
The translationObjectY is an extended function:
fun translationObjectY(
targetView: View?,
startY: Float,
endY: Float,
duration: Long = 200L
) : ObjectAnimator {
return ObjectAnimator.ofFloat(targetView, "translationY", startY, endY).apply {
this.duration = duration
interpolator = LinearOutSlowInInterpolator()
start()
}
}
And I finally create a custom Recyclerview:
class CustomRecyclerView(
context: Context,
attrs: AttributeSet?,
defStyle: Int,
) : RecyclerView(context, attrs, defStyle) {
constructor(context: Context)
: this(context, null, 0)
constructor(context: Context, attrs: AttributeSet)
: this(context, attrs, 0)
init {
this.addOnScrollListener(object : RecyclerView.OnScrollListener() {
override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
if (dy > 0) {
// Scrolling up
hideBottomMenu()
} else {
// Scrolling down
showBottomMenu()
}
}
override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
}
})
}
private fun hideBottomMenu() {
(context as? MainActivity)?.slideDown()
}
private fun showBottomMenu() {
(context as? MainActivity)?.slideUp()
}
}
You can then implement it in your fragment like this:
<com.studio.mattiaferigutti.kamasutra.custom.CustomRecyclerView
android:id="#+id/searchRecycler"
android:layout_width="match_parent"
android:layout_height="match_parent" />

Just simply add this in your xml
<BottomNavigationView
....
....
app:layout_behavior="#string/hide_bottom_view_on_scroll_behavior"/>

This can help somebody
read more:https://material.io/develop/android/components/app-bars-bottom
add
app:hideOnScroll="true"
inside BottomAppBar Like below:
<androidx.coordinatorlayout.widget.CoordinatorLayout
...>
...
<com.google.android.material.bottomappbar.BottomAppBar
...
app:hideOnScroll="true"
/>
...
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Use this code : when Scrolling down the Recyclerview to your fragment will hide the bottom navigation. then when Scrolled Up it will show the Bottom nav.
private View view;
private AppCompatActivity activity;
private ChipNavigationBar chipNavigationBar;
//...............................................
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (view == null) {
view = inflater.inflate(R.layout.list_fragment, container, false);
hide_NavigationBar_adwhen_Scrolling();
}
return view;
}
//...........................................................
private void hide_NavigationBar_adwhen_Scrolling() {
activity = (AppCompatActivity) view.getContext();
chipNavigationBar = activity.findViewById(R.id.chipNavigation);
RecyclerView recyclerView = view.findViewById(R.id.recylerView);
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy > 0) {//on_Scrolled_down
// chipNavigationBar.animate().translationY(200).setDuration(500);
chipNavigationBar.animate().translationY(banner_ad_card_1.getHeight()).setDuration(1000);
} else {//on_Scrolled_up
chipNavigationBar.setVisibility(View.VISIBLE);
chipNavigationBar.animate().translationY(0).setDuration(1000);
// chipNavigationBar.setItemSelected(R.id.home, true);
}
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
});
}

BottomSheetDialogFragment - Allow scrolling child

I have a BottomSheetDialogFragment with a RecyclerView. The problem is, I want to disable the drag close function of the BottomSheetDialogFragment as long as the RecyclerView is not scrolled up (currently I can't scroll my RecyclerView as the attempt will always close the BottomSheetDialogFragment). Any ideas how to achieve this?

RecyclerView scrolling problem in BottomSheetDialog can be solved by this way.
from: https://android.jlelse.eu/recyclerview-within-nestedscrollview-scrolling-issue-3180b5ad2542
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v4.widget.NestedScrollView
android:id="#+id/nestedScrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</LinearLayout>

Try this in your Fragment that extends RecyclerView in onCreateView
recyclerView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
v.getParent().requestDisallowInterceptTouchEvent(true);
v.onTouchEvent(event);
return true;
}
});

Just add one (!) attribute to your layout:
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/receiversList"
android:nestedScrollingEnabled="false"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
android:nestedScrollingEnabled="false" doing all the job.
Also, if you wrap around your RecyclerView with SwipeRefreshLayout - refresh function will continue to work. And even you put your layout with more complex Views, your BottomSheetDialog will continue to support drag-down-to-dismiss behaviour (If touch with swipe down gesture occurs outside of RecyclerView & SwipeRefreshLayout).

Just treat it as a BottomSheetDialog , and simply disable its dragging or sliding when touch .
When create a BottomSheetDialog , it will automatically wrap your layout in a
CoordinatorLayout , so if you want to get a behaviour from your view , call
final BottomSheetBehavior behavior = BottomSheetBehavior.from((View) view.getParent());
Then through this behaviour, you can do what you need.
final BottomSheetBehavior behavior = BottomSheetBehavior.from((View) view.getParent());
behavior.setHideable(false);
behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
#Override
public void onStateChanged(#NonNull View bottomSheet, int newState) {
}
#Override
public void onSlide(#NonNull View bottomSheet, float slideOffset) {
behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
}
});
This worked for me.Hope it helps.

When recycle view has scope to scroll, bottom sheet will remain expanded. But if recycle view has no scroll to up direction, than drag from up, will revert normal behaviour.
behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
behavior.addBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
#Override
public void onStateChanged(#NonNull View bottomSheet, int newState) {
if (newState == BottomSheetBehavior.STATE_HIDDEN) {
dismiss();
}
if (newState == BottomSheetBehavior.STATE_DRAGGING) {
if(!recyclerView.canScrollVertically(1)) {
behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
}
}
}
#Override
public void onSlide(#NonNull View bottomSheet, float slideOffset) {
}
});

try this solution :
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="#+id/layout_form"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<!-- elements-->
<!-- elements-->
</LinearLayout>
</androidx.core.widget.NestedScrollView>

Change the Behaviour in the BottomSheetDialogFragment in setupDialog method:
CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) ((View) contentView.getParent()).getLayoutParams();
final CoordinatorLayout.Behavior behavior = layoutParams.getBehavior();
if (behavior != null && behavior instanceof BottomSheetBehavior) {
((BottomSheetBehavior) behavior).setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
#Override
public void onStateChanged(#NonNull View bottomSheet, int newState) {
if (newState == BottomSheetBehavior.STATE_HIDDEN) {
dismiss();
}
if (newState == BottomSheetBehavior.STATE_DRAGGING) {
((BottomSheetBehavior) behavior).setState(BottomSheetBehavior.STATE_EXPANDED);
}
}
#Override
public void onSlide(#NonNull View bottomSheet, float slideOffset) {
}
});
}

I had the same situation and what worked for me is just a single line of code inside onCreate function.
What you have to do is just enable recyclerViews nested scrolling.
recyclerView.setNestedScrollingEnabled(true);

I had the same problem recently on my project and I have tried all the answer suggested in this and in other threads on SO but without luck so I decided to solve it my way.
Just a note, my situation it's that I have a BottomSheetDialog with a complex layout that result in something like this
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="_mainLayout"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<View
android:id=" />
<LinearLayout
android:id="">
<ImageView
android:id=""/>
<LinearLayout
android:id="">
<TextView
android:id="" />
<TextView
android:id=""/>
</LinearLayout>
<LinearLayout
android:id="">
<TextView
android:id=""/>
</LinearLayout>
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:layout_marginTop="10dp"
android:id=""
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
<Button
android:id="">
<Button
android:id="">
</LinearLayout>
Basically what it's needed it's to add a BottomSheetBehavior to the main layout of the dialog
_bottomSheetBehavior = BottomSheetBehavior.From((View)_mainLayout.Parent);
once we have this we create a custom BottomSheetCallback implementation and we add it to the behavior
_bottomSheetCallback = new BottomSheetFullScreenCallback(_bottomSheetBehavior);
_bottomSheetBehavior.AddBottomSheetCallback(_bottomSheetCallback);
last step it's to create a custo OntouchListener that we will add to the RecyclerView
_recyclerView.SetOnTouchListener(new MyTouchListener(_bottomSheetBehavior));
Now we have everything in place and we just need to manage the touch on the recyclerView. So in our custom OnTouchListener we implement the OnTouch method in this way
public bool OnTouch(View view, MotionEvent e)
{
if (e.Action == MotionEventActions.Down || e.Action == MotionEventActions.Move)
{
_bottomSheetBehavior.Draggable = false;
}
if (e.Action == MotionEventActions.Up)
{
_bottomSheetBehavior.Draggable = true;
}
return true;
}
Once we have done this we need to be sure that the OnSlide event of the custom BottomSheetCallback will never be called once the bottomSheetBehavior it's not draggable, and we can do this in the following way:
public override void OnSlide(View bottomSheet, float slideOffset)
{
if (_bottomSheetBehavior.Draggable)
{
OnSlideEvent?.Invoke(this, slideOffset);
}
}
And that's it ;)

To scroll RecyclerView inside BottomSheet can use this way:
Add android:focusableInTouchMode="true" to RecyclerView in file XML.
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="5dp"
android:clipToPadding="false"
android:focusableInTouchMode="true"
android:paddingBottom="50dp" />
- In func onCreateDialog for BottomSheet:
+ where: maxDesiredHeight is set fixed size of BottomSheet.
+ this.isDraggable = false -> disabling dragging on BottomSheet.
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
val dialog = super.onCreateDialog(savedInstanceState) as BottomSheetDialog
dialog.setOnShowListener {
dialog.findViewById<FrameLayout>(com.google.android.material.R.id.design_bottom_sheet)!!
.apply {
val maxDesiredHeight = (resources.displayMetrics.heightPixels * 0.95).toInt()
val bottomSheetLayoutParams = this.layoutParams
bottomSheetLayoutParams.height = maxDesiredHeight
this.layoutParams = bottomSheetLayoutParams
BottomSheetBehavior.from(this).apply {
this.state = BottomSheetBehavior.STATE_EXPANDED
this.isDraggable = false
}
}
}
return dialog
}
- Call the setOnTouchListener function for RecyclerView:
Recycler.setOnTouchListener { v, event ->
v.parent.requestDisallowInterceptTouchEvent(true)
v.onTouchEvent(event)
true
}

With Constraint layout
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rv_team_mates"
android:layout_width="#dimen/dp_0"
android:layout_height="#dimen/dp_0"
android:layout_marginVertical="#dimen/dp_20"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/txt_title_custom"
app:layout_constraintBottom_toBottomOf="parent"/>

Put your RecyclerView under NestedScrollView where NestedScroll is parent of recycler

FAB Behavior when showing CardView (Up & Down)

I want to show a CardView as prompt like in Material Guidelines Specs:
https://www.google.com/design/spec/growth-communications/onboarding.html#onboarding-quickstart
Here is the link to the image:
Image
I've changed the behavior of the FAB Button like this and set to the .xml file:
public class FABBehavior extends FloatingActionButton.Behavior {
public FABBehavior(Context context, AttributeSet attr) {
super();
}
#Override
public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
return dependency instanceof CardView;
}
#Override
public boolean onDependentViewChanged(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
float translationY = Math.min(0, dependency.getTranslationY() - dependency.getHeight());
child.setTranslationY(translationY);
return true;
}
}
My .xml file look like this:
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.nearme.client.activities.fragments.ScannerFragment">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:title="#string/title_scanner"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="#layout/fragment_scanner_content" />
<android.support.v7.widget.CardView
android:id="#+id/cvBluetooth"
android:layout_width="match_parent"
android:layout_height="150dp"
android:animateLayoutChanges="true"
android:layout_gravity="bottom" >
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Prueba" />
</android.support.v7.widget.CardView>
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right|bottom|end"
android:layout_margin="#dimen/fab_margin"
app:layout_behavior="com.nearme.client.utils.FABBehavior"
android:src="#android:drawable/ic_dialog_email" />
And the click listener of the FAB Button is this:
View.OnClickListener onClick = new View.OnClickListener() {
#Override
public void onClick(View v) {
if (v == fab) {
if (cardBluetooth.isShown()) {
cardBluetooth.setVisibility(View.GONE);
} else
cardBluetooth.setVisibility(View.VISIBLE);
}
}
};
The problem is when the CardView's visibility goes GONE the FAB button remain up in its position.
How can I update the position of the FAB when the CardView is GONE?
Even if I set the CardView in the CoordinatorLayout dinamically and remove it doesnt work.

Well, the problem was that onDependentViewChangedfrom FloatingActionButton.Behavior only get called when the dependent view have changed its position. But I only was changing its visibility so it didnt get called.
Now in the onClick I add to the view and remove it:
View.OnClickListener onClick = new View.OnClickListener() {
#Override
public void onClick(View v) {
if (v == fab) {
if (cardBluetooth.isShown()) {
coordinatorLayout.removeView(cardBluetooth);
} else
coordinatorLayout.addView(cardBluetooth);
}
}
};
And in FloatingActionButton.Behavior I added:
#Override
public void onDependentViewRemoved(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
child.animate().translationY(0);
child.setTranslationY(0);
}
And this is the result:
GIF of result

Change the method layoutDependsOn method according to this:
#Override
public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
return dependency instanceof CardView && onDependentViewChanged(parent, child, dependency);
}
Otherwise, the fab button is going to move up only the first time it gets clicked.

Toolbar in AppBarLayout is scrollable although RecyclerView has not enough content to scroll

Is it really intended that the Toolbar in a AppBarLayout is scrollable although the main container with the "appbar_scrolling_view_behavior" has not enough content to really scroll?
What I have tested so far:
When I use a NestedScrollView (with "wrap_content" attribute) as main container and a TextView as child, the AppBarLayout works properly and does not scroll.
However, when I use a RecyclerView with only a few entries and the "wrap_content" attribute (so that there is no need to scroll), the Toolbar in the AppBarLayout is scrollable even though the RecyclerView never receives a scroll event (tested with a OnScrollChangeListener).
Here's my layout code:
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/coordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:theme="#style/ToolbarStyle" />
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
With the following effect that the toolbar is scrollable although it's not necessary:
I've also found a way to deal with this by checking if all RecyclerView items are visible and using the setNestedScrollingEnabled() method of the RecyclerView.
Nevertheless, it does seem more like a bug as intended to me. Any opinions? :D
EDIT #1:
For people who are might be interested in my current solution, I had to put the setNestedScrollingEnabled() logic in the postDelayed() method of a Handler with 5 ms delay due to the LayoutManager which always returned -1 when calling the methods to find out whether the first and the last item is visible.
I use this code in the onStart() method (after my RecyclerView has been initialized) and every time after a content change of the RecyclerView occurs.
final LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
//no items in the RecyclerView
if (mRecyclerView.getAdapter().getItemCount() == 0)
mRecyclerView.setNestedScrollingEnabled(false);
//if the first and the last item is visible
else if (layoutManager.findFirstCompletelyVisibleItemPosition() == 0
&& layoutManager.findLastCompletelyVisibleItemPosition() == mRecyclerView.getAdapter().getItemCount() - 1)
mRecyclerView.setNestedScrollingEnabled(false);
else
mRecyclerView.setNestedScrollingEnabled(true);
}
}, 5);
EDIT #2:
I just played around with a new app and it seems that this (unintended) behavior has been fixed in support library version 23.3.0 (or even earlier). Thus, there is no need for workarounds anymore!

Edit 2:
Turns out the only way to ensure Toolbar is not scrollable when RecyclerView is not scrollable is to set setScrollFlags programmatically which requires to check if RecyclerView's is scrollable. This check has to be done every time adapter is modified.
Interface to communicate with the Activity:
public interface LayoutController {
void enableScroll();
void disableScroll();
}
MainActivity:
public class MainActivity extends AppCompatActivity implements
LayoutController {
private CollapsingToolbarLayout collapsingToolbarLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
collapsingToolbarLayout =
(CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
final FragmentManager manager = getSupportFragmentManager();
final Fragment fragment = new CheeseListFragment();
manager.beginTransaction()
.replace(R.id.root_content, fragment)
.commit();
}
#Override
public void enableScroll() {
final AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams)
collapsingToolbarLayout.getLayoutParams();
params.setScrollFlags(
AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL
| AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS
);
collapsingToolbarLayout.setLayoutParams(params);
}
#Override
public void disableScroll() {
final AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams)
collapsingToolbarLayout.getLayoutParams();
params.setScrollFlags(0);
collapsingToolbarLayout.setLayoutParams(params);
}
}
activity_main.xml:
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/drawer_layout"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:id="#+id/root_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="fill_vertical"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>
</android.support.v4.widget.DrawerLayout>
Test Fragment:
public class CheeseListFragment extends Fragment {
private static final int DOWN = 1;
private static final int UP = 0;
private LayoutController controller;
private RecyclerView rv;
#Override
public void onAttach(Context context) {
super.onAttach(context);
try {
controller = (MainActivity) getActivity();
} catch (ClassCastException e) {
throw new RuntimeException(getActivity().getLocalClassName()
+ "must implement controller.", e);
}
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rv = (RecyclerView) inflater.inflate(
R.layout.fragment_cheese_list, container, false);
setupRecyclerView(rv);
// Find out if RecyclerView are scrollable, delay required
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
if (rv.canScrollVertically(DOWN) || rv.canScrollVertically(UP)) {
controller.enableScroll();
} else {
controller.disableScroll();
}
}
}, 100);
return rv;
}
private void setupRecyclerView(RecyclerView recyclerView) {
final LinearLayoutManager layoutManager = new LinearLayoutManager(recyclerView.getContext());
recyclerView.setLayoutManager(layoutManager);
final SimpleStringRecyclerViewAdapter adapter =
new SimpleStringRecyclerViewAdapter(
getActivity(),
// Test ToolBar scroll
getRandomList(/* with enough items to scroll */)
// Test ToolBar pin
getRandomList(/* with only 3 items*/)
);
recyclerView.setAdapter(adapter);
}
}
Sources:
Change scroll flags programmatically
Original code by Chris Banes
Need a postDelayed to ensure RecyclerView children are ready for calculations
Edit:
You should CollapsingToolbarLayout to control the behaviour.
Adding a Toolbar directly to an AppBarLayout gives you access to the enterAlwaysCollapsed and exitUntilCollapsed scroll flags, but not the detailed control on how different elements react to collapsing.
[...] setup uses CollapsingToolbarLayout’s app:layout_collapseMode="pin" to ensure that the Toolbar itself remains pinned to the top of the screen while the view collapses.http://android-developers.blogspot.com.tr/2015/05/android-design-support-library.html
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<android.support.v7.widget.Toolbar
android:id="#+id/drawer_toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_collapseMode="pin"/>
</android.support.design.widget.CollapsingToolbarLayout>
Add
app:layout_collapseMode="pin"
to your Toolbar in xml.
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:layout_collapseMode="pin"
app:theme="#style/ToolbarStyle" />

So, proper credit, this answer almost solved it for me https://stackoverflow.com/a/32923226/5050087. But since it was not showing the toolbar when you actually had an scrollable recyclerview and its last item was visible (it would not show the toolbar on the first scroll up), I decided to modify it and adapt it for an easier implementation and for dynamic adapters.
First, you must create a custom layout behavior for you appbar:
public class ToolbarBehavior extends AppBarLayout.Behavior{
private boolean scrollableRecyclerView = false;
private int count;
public ToolbarBehavior() {
}
public ToolbarBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean onInterceptTouchEvent(CoordinatorLayout parent, AppBarLayout child, MotionEvent ev) {
return scrollableRecyclerView && super.onInterceptTouchEvent(parent, child, ev);
}
#Override
public boolean onStartNestedScroll(CoordinatorLayout parent, AppBarLayout child, View directTargetChild, View target, int nestedScrollAxes, int type) {
updatedScrollable(directTargetChild);
return scrollableRecyclerView && super.onStartNestedScroll(parent, child, directTargetChild, target, nestedScrollAxes, type);
}
#Override
public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, float velocityX, float velocityY, boolean consumed) {
return scrollableRecyclerView && super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
}
private void updatedScrollable(View directTargetChild) {
if (directTargetChild instanceof RecyclerView) {
RecyclerView recyclerView = (RecyclerView) directTargetChild;
RecyclerView.Adapter adapter = recyclerView.getAdapter();
if (adapter != null) {
if (adapter.getItemCount()!= count) {
scrollableRecyclerView = false;
count = adapter.getItemCount();
RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
if (layoutManager != null) {
int lastVisibleItem = 0;
if (layoutManager instanceof LinearLayoutManager) {
LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;
lastVisibleItem = Math.abs(linearLayoutManager.findLastCompletelyVisibleItemPosition());
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
int[] lastItems = staggeredGridLayoutManager.findLastCompletelyVisibleItemPositions(new int[staggeredGridLayoutManager.getSpanCount()]);
lastVisibleItem = Math.abs(lastItems[lastItems.length - 1]);
}
scrollableRecyclerView = lastVisibleItem < count - 1;
}
}
}
} else scrollableRecyclerView = true;
}
}
Then, you only need to define this behavior for you appbar in your layout file:
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
app:layout_behavior="com.yourappname.whateverdir.ToolbarBehavior"
>
I haven't tested it for screen rotation so let me know if it works like this. I guess it should work as I don't think the count variable is saved when the rotation happens, but let me know if it doesn't.
This was the easiest and cleanest implementation for me, enjoy it.

It is not a bug, all the events in a viewGroup are handled this way. Because your recyclerview is a child of coordinatorLayout so whenever the event is generated, it is first checked for parent and if parent is not interested only then it is passed down to child.
See google documentation

Something like this in a LayoutManager subclass seems to result in the desired behavior:
#Override
public boolean canScrollVertically() {
int firstCompletelyVisibleItemPosition = findFirstCompletelyVisibleItemPosition();
if (firstCompletelyVisibleItemPosition == RecyclerView.NO_POSITION) return false;
int lastCompletelyVisibleItemPosition = findLastCompletelyVisibleItemPosition();
if (lastCompletelyVisibleItemPosition == RecyclerView.NO_POSITION) return false;
if (firstCompletelyVisibleItemPosition == 0 &&
lastCompletelyVisibleItemPosition == getItemCount() - 1)
return false;
return super.canScrollVertically();
}
The documentation for canScrollVertically() says:
/**
* Query if vertical scrolling is currently supported. The default implementation
* returns false.
*
* #return True if this LayoutManager can scroll the current contents vertically
*/
Notice the wording of "can scroll the current contents vertically", which I believe implies that the current state should be reflected by the return value.
However, that is not done by any of the LayoutManager subclasses provided through the v7 recyclerview library (23.1.1), which makes me somewhat hesitant whether it is a correct solution; it might cause undesired effects in other situations than the one discussed in this question.

I've implemented it using my own Behavior class which might be attached to AppBarLayout:
public class CustomAppBarLayoutBehavior extends AppBarLayout.Behavior {
private RecyclerView recyclerView;
private int additionalHeight;
public CustomAppBarLayoutBehavior(RecyclerView recyclerView, int additionalHeight) {
this.recyclerView = recyclerView;
this.additionalHeight = additionalHeight;
}
public boolean isRecyclerViewScrollable(RecyclerView recyclerView) {
return recyclerView.computeHorizontalScrollRange() > recyclerView.getWidth() || recyclerView.computeVerticalScrollRange() > (recyclerView.getHeight() - additionalHeight);
}
#Override
public boolean onStartNestedScroll(CoordinatorLayout parent, AppBarLayout child, View directTargetChild, View target, int nestedScrollAxes) {
if (isRecyclerViewScrollable(mRecyclerView)) {
return super.onStartNestedScroll(parent, child, directTargetChild, target, nestedScrollAxes);
}
return false;
}
}
And below is the code how to set this behavior:
final View appBarLayout = ((DrawerActivity) getActivity()).getAppBarLayoutView();
CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
layoutParams.setBehavior(new AppBarLayoutNoEmptyScrollBehavior(recyclerView, getResources().getDimensionPixelSize(R.dimen.control_bar_height)));

I suggested you try this sample that for support desing library elements.
this a layout like your layout in the sample.
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:layout_scrollFlags="scroll|enterAlways" />
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>

Thanks, I created a custom class of RecyclerView but the key is still using setNestedScrollingEnabled(). It worked fine on my side.
public class RecyclerViewCustom extends RecyclerView implements ViewTreeObserver.OnGlobalLayoutListener
{
public RecyclerViewCustom(Context context)
{
super(context);
}
public RecyclerViewCustom(Context context, #Nullable AttributeSet attrs)
{
super(context, attrs);
}
public RecyclerViewCustom(Context context, #Nullable AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
}
/**
* This supports scrolling when using RecyclerView with AppbarLayout
* Basically RecyclerView should not be scrollable when there's no data or the last item is visible
*
* Call this method after Adapter#updateData() get called
*/
public void addOnGlobalLayoutListener()
{
this.getViewTreeObserver().addOnGlobalLayoutListener(this);
}
#Override
public void onGlobalLayout()
{
// If the last item is visible or there's no data, the RecyclerView should not be scrollable
RecyclerView.LayoutManager layoutManager = getLayoutManager();
final RecyclerView.Adapter adapter = getAdapter();
if (adapter == null || adapter.getItemCount() <= 0 || layoutManager == null)
{
setNestedScrollingEnabled(false);
}
else
{
int lastVisibleItemPosition = ((LinearLayoutManager) layoutManager).findLastCompletelyVisibleItemPosition();
boolean isLastItemVisible = lastVisibleItemPosition == adapter.getItemCount() - 1;
setNestedScrollingEnabled(!isLastItemVisible);
}
unregisterGlobalLayoutListener();
}
private void unregisterGlobalLayoutListener()
{
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
{
getViewTreeObserver().removeOnGlobalLayoutListener(this);
}
else
{
getViewTreeObserver().removeGlobalOnLayoutListener(this);
}
}
}

I would like to add a little to user3623735's answer. The following code is absolutely incorrect.
// Find out if RecyclerView are scrollable, delay required
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
if (rv.canScrollVertically(DOWN) || rv.canScrollVertically(UP)) {
controller.enableScroll();
} else {
controller.disableScroll();
}
}
}, 100);
And even when it works - it doesn't cover all cases. There is absolutely no guarantee that a data will be displayed in 100 ms, and the data can stretch the height of the view in the process of working with it, not only in the onCreateView method. That's why you should use next code and track changes in view height:
view.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
if(bottom != oldBottom)
{
mActivity.setScrollEnabled(view.canScrollVertically(0) || view.canScrollVertically(1));
}
}
});
Moreover no need to create two separated method to control scrolling status, you should use one setScrollEnabled method:
public void setScrollEnabled(boolean enabled) {
final AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams)
mToolbar.getLayoutParams();
params.setScrollFlags(enabled ?
AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS : 0);
mToolbar.setLayoutParams(params);
}

In your Toolbar remove the scroll flag, leaving only the enterAlways flag and you should get the effect you intended. For completeness, your layout should look like:
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/coordinatorLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="enterAlways"
app:theme="#style/ToolbarStyle" />
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>