I have a RecyclerView with a CardView as the root element of the row item layout. I managed to have a ripple effect to CardView using below list item layout as described here.
Row item layout:
<androidx.cardview.widget.CardView 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="wrap_content"
android:layout_margin="#dimen/margin_8dp"
android:background="?android:attr/selectableItemBackground"
android:clickable="true"
android:focusable="true"
android:focusableInTouchMode="true"
android:foreground="?android:attr/selectableItemBackground"
app:cardBackgroundColor="#color/cyan"
app:cardCornerRadius="20dp"
app:cardElevation="5dp">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/transparent"
android:padding="#dimen/margin_8dp">
<!-- Underlying views-->
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
The problem is that to have a click action on a row item in the RecyclerView adapter requires a couple of taps, the first tap for selecting the item and showing the ripple effect, and the second tap for the actual click to trigger View.OnClickListener.
Using android:focusableInTouchMode = "true" attribute in CardView is the reason for the double tap; but disabling it, also disable the ripple effect consequently.
I tried to use a custom Ripple effect as in this answer, but doesn't work. Also tried to have the ripple effect on the underlying CardView root element as in this answer, but still nothing new.
Similar thing for using the button style as in here.
And I have a transnational itemView click listener in RecyclerView adapter within the view holder
class ViewHolder extends RecyclerView.ViewHolder {
ViewHolder(#NonNull final View itemView) {
super(itemView);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
}
});
}
}
Replaced View.OnClickListener with View.OnFocusChangeListener, and when the row item gets a focus after it's been clicked, I run the same code as in onClick callback.
But that doesn't give the ripple effect a chance to show up, so posted that with some delay.
itemView.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
if (hasFocus)
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
// Do whatever done in onClick()
}
}, 10); // delay to give the ripple effect a chance to show
}
});
I wish if there's another solution without any delay.
I solved this by totally removing android:focusableInTouchMode = "true" & android:foreground from the CardView, and adding the ripple effect to the root item within the CardView with android:background="?android:attr/selectableItemBackground"
<androidx.cardview.widget.CardView 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="wrap_content"
android:layout_margin="#dimen/margin_8dp"
app:cardBackgroundColor="#color/cyan"
app:cardCornerRadius="20dp"
app:cardElevation="5dp">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?android:attr/selectableItemBackground"
android:padding="#dimen/margin_8dp">
<!-- Underlying views-->
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
Background
We have quite a complex layout that has CollapsingToolbarLayout in it, together with a RecyclerView at the bottom.
In certain cases, we temporarily disable the expanding/collapsing of the CollapsingToolbarLayout, by calling setNestedScrollingEnabled(boolean) on the RecyclerView.
The problem
This usually works fine.
However, on some (bit rare) cases, slow scrolling on the RecyclerView gets semi-blocked, meaning it tries to scroll back when scrolling down. It's as if it has 2 scrolling that fight each other (scroll up and scroll down):
The code to trigger this is as such:
res/layout/activity_scrolling.xml
<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.example.user.myapplication.ScrollingActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar"
android:layout_width="match_parent"
android:layout_height="#dimen/app_bar_height"
android:fitsSystemWindows="true"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/toolbar_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed|snap">
<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.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/nestedView"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_anchor="#id/app_bar"
app:layout_anchorGravity="bottom|end">
<Button
android:id="#+id/disableNestedScrollingButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="disable"/>
<Button
android:id="#+id/enableNestedScrollingButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="enable"
/>
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
ScrollingActivity.java
public class ScrollingActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_scrolling);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
final RecyclerView nestedView = (RecyclerView) findViewById(R.id.nestedView);
findViewById(R.id.disableNestedScrollingButton).setOnClickListener(new OnClickListener() {
#Override
public void onClick(final View v) {
nestedView.setNestedScrollingEnabled(false);
}
});
findViewById(R.id.enableNestedScrollingButton).setOnClickListener(new OnClickListener() {
#Override
public void onClick(final View v) {
nestedView.setNestedScrollingEnabled(true);
}
});
nestedView.setLayoutManager(new LinearLayoutManager(this));
nestedView.setAdapter(new Adapter() {
#Override
public ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(
android.R.layout.simple_list_item_1,
parent,
false)) {
};
}
#Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
((TextView) holder.itemView.findViewById(android.R.id.text1)).setText("item " + position);
}
#Override
public int getItemCount() {
return 100;
}
});
}
}
What I've tried
At first I thought it's because of something else (I thought it's a weird combination with DrawerLayout), but then I've found a minimal sample to show it, and it's just as I thought: it's all because of the setNestedScrollingEnabled.
I tried to report about this on Google's website (here), hoping it will get fixed if it's a real bug. If you wish to try it out, or watch the videos of the issue, go there, as I can't upload them all here (too large and too many files).
I've also tried to use special flags as instructed on other posts (examples: here, here, here, here and here) , but none helped. In fact each of them had an issue, whether it's staying in expanded mode, or scrolling in a different way than what I do.
The questions
Is this a known issue? Why does it happen?
Is there a way to overcome this?
Is there perhaps an alternative to calling this function of setNestedScrollingEnabled ? One without any issues of scrolling or locking the state of the CollapsingToolbarLayout ?
This is an alternate approach to achieving the same goal as this answer. While that answer used Reflection, this answer does not, but the reasoning remains the same.
Why is this happening?
The problem is that RecyclerView sometimes uses a stale value for the member variable mScrollOffset. mScrollOffset is set in only two places in RecyclerView: dispatchNestedPreScroll and dispatchNestedScroll. We are only concerned with dispatchNestedPreScroll. This method is invoked by RecyclerView#onTouchEvent when it handles MotionEvent.ACTION_MOVE events.
The following is from the documentation for dispatchNestedPreScroll.
dispatchNestedPreScroll
boolean dispatchNestedPreScroll (int dx,
int dy,
int[] consumed,
int[] offsetInWindow)
Dispatch one step of a nested scroll in progress before this view consumes any portion of it.
Nested pre-scroll events are to nested scroll events what touch intercept is to touch. dispatchNestedPreScroll offers an opportunity for the parent view in a nested scrolling operation to consume some or all of the scroll operation before the child view consumes it.
...
offsetInWindow int: Optional. If not null, on return this will contain the offset in local view coordinates of this view from before this operation to after it completes. View implementations may use this to adjust expected input coordinate tracking.
offsetInWindow is actually an int[2] with the second index representing the y shift to be applied to the RecyclerView due to nested scrolling.
RecyclerView#DispatchNestedPrescroll resolves to a method with the same name in NestedScrollingChildHelper.
When RecyclerView calls dispatchNestedPreScroll,
mScrollOffset is used as the offsetInWindow argument. So any changes made to offsetInWindow directly updates mScrollOffset. dispatchNestedPreScroll updates mScrollOffset as long as nested scrolling is in effect. If nested scrolling is not in effect, then mScrollOffset is not updated and proceeds with the value that was last set by dispatchNestedPreScroll. Thus, when nested scrolling is turned off, the value of mScrollOffset becomes immediately stale but RecyclerView continues to use it.
The correct value of mScrollOffset[1] upon return from dispatchNestedPreScroll is the amount to adjust for input coordinate tracking (see above). In RecyclerView the following lines adjusts the y touch coordinate:
mLastTouchY = y - mScrollOffset[1];
If mScrollOffset[1] is, let's say, -30 (because it is stale and should be zero) then mLastTouchY will be off by +30 pixels (--30=+30). The effect of this miscalculation is that it will appear that the touch occurred further down the screen than it really did. So, a slow downward scroll will actually scrolls up and an upward scroll will scroll faster. (If a downward scroll is fast enough to overcome this 30px barrier, then downward scrolling will occur but more slowly than it should.) Upward scrolling will be overly quick since the app thinks more space has been covered.
mScrollOffset will continue as a stale variable until nested scrolling is turned on and dispatchNestedPreScroll once again reports the correct value in mScrollOffset.
Approach
Since mScrollOffset[1] has a stale value under certain circumstances, the goal is to set it to the correct value under those circumstances. This value should be zero when nested scrolling is not taking place, i.e., When the AppBar is expanded or collapsed. Unfortunately, mScrollOffset is local to RecyclerView and there is no setter for it. To gain access to mScrollOffset without resorting to Reflection, a custom RecyclerView is created that overrides dispatchNestedPreScroll. The fourth agument is offsetInWindow which is the variable we need to change.
A stale mScrollOffset occurs whenever nested scrolling is disabled for the RecyclerView. An additional condition we will impose is that the AppBar must be idle so we can safely say that mScrollOffset[1] should be zero. This is not an issue since the CollapsingToolbarLayout specifies snap in the scroll flags.
In the sample app, ScrollingActivity has been modified to record when the AppBar is expanded and closed. A callback has also been created (clampPrescrollOffsetListener) that will return true when our two conditions are met. Our overridden dispatchNestedPreScroll will invoke this callback and clamp mScrollOffset[1] to zero on a true response.
The updated source file for ScrollingActivity is presented below as is the custom RecyclerView - MyRecyclerView.
The XML layout file must be changed to reflect the custom MyRecyclerView.
ScrollingActivity
public class ScrollingActivity extends AppCompatActivity
implements MyRecyclerView.OnClampPrescrollOffsetListener {
private CollapsingToolbarLayout mCollapsingToolbarLayout;
private AppBarLayout mAppBarLayout;
private MyRecyclerView mNestedView;
// This variable will be true when the app bar is completely open or completely collapsed.
private boolean mAppBarIdle = true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_scrolling);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mNestedView = (MyRecyclerView) findViewById(R.id.nestedView);
mAppBarLayout = (AppBarLayout) findViewById(R.id.app_bar);
mCollapsingToolbarLayout = (CollapsingToolbarLayout) findViewById(R.id.toolbar_layout);
// Set the listener for the patch code.
mNestedView.setOnClampPrescrollOffsetListener(this);
// Listener to determine when the app bar is collapsed or fully open (idle).
mAppBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
#Override
public final void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
mAppBarIdle = verticalOffset == 0
|| verticalOffset <= appBarLayout.getTotalScrollRange();
}
});
findViewById(R.id.disableNestedScrollingButton).setOnClickListener(new OnClickListener() {
#Override
public void onClick(final View v) {
// If the AppBar is fully expanded or fully collapsed (idle), then disable
// expansion and apply the patch; otherwise, set a flag to disable the expansion
// and apply the patch when the AppBar is idle.
setExpandEnabled(false);
}
});
findViewById(R.id.enableNestedScrollingButton).setOnClickListener(new OnClickListener() {
#Override
public void onClick(final View v) {
setExpandEnabled(true);
}
});
mNestedView.setLayoutManager(new LinearLayoutManager(this));
mNestedView.setAdapter(new Adapter() {
#Override
public ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(
android.R.layout.simple_list_item_1,
parent,
false)) {
};
}
#Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
((TextView) holder.itemView.findViewById(android.R.id.text1)).setText("item " + position);
}
#Override
public int getItemCount() {
return 100;
}
});
}
private void setExpandEnabled(boolean enabled) {
mNestedView.setNestedScrollingEnabled(enabled);
}
// Return "true" when the app bar is idle and nested scrolling is disabled. This is a signal
// to the custom RecyclerView to clamp the y prescroll offset to zero.
#Override
public boolean clampPrescrollOffsetListener() {
return mAppBarIdle && !mNestedView.isNestedScrollingEnabled();
}
private static final String TAG = "ScrollingActivity";
}
MyRecyclerView
public class MyRecyclerView extends RecyclerView {
private OnClampPrescrollOffsetListener mPatchListener;
public MyRecyclerView(Context context) {
super(context);
}
public MyRecyclerView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyRecyclerView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
// Just a call to super plus code to force offsetInWindow[1] to zero if the patchlistener
// instructs it.
#Override
public boolean dispatchNestedPreScroll(int dx, int dy, int[] consumed, int[] offsetInWindow) {
boolean returnValue;
int currentOffset;
returnValue = super.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow);
currentOffset = offsetInWindow[1];
Log.d(TAG, "<<<<dispatchNestedPreScroll: " + currentOffset);
if (mPatchListener.clampPrescrollOffsetListener() && offsetInWindow[1] != 0) {
Log.d(TAG, "<<<<dispatchNestedPreScroll: " + currentOffset + " -> 0");
offsetInWindow[1] = 0;
}
return returnValue;
}
public void setOnClampPrescrollOffsetListener(OnClampPrescrollOffsetListener patchListener) {
mPatchListener = patchListener;
}
public interface OnClampPrescrollOffsetListener {
boolean clampPrescrollOffsetListener();
}
private static final String TAG = "MyRecyclerView";
}
Actually, you might be looking at the problem in the wrong way.
The only thing you need is to set the Toolbar flags accordingly. You don't really anything else so I would say that your layout should be simplified to:
<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.example.user.myapplication.ScrollingActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar"
android:layout_width="match_parent"
android:layout_height="#dimen/app_bar_height"
android:fitsSystemWindows="true"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay"
app:title="Title" />
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/nestedView"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_anchor="#id/app_bar"
app:layout_anchorGravity="bottom|end">
<Button
android:id="#+id/disableNestedScrollingButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="disable"/>
<Button
android:id="#+id/enableNestedScrollingButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="enable"
/>
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
Then when you wish to disable the collapsing just set your toolbar flags:
// To disable collapsing
AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams) toolbar.getLayoutParams();
params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SNAP);
toolbar.setLayoutParams(params);
And to enable
// To enable collapsing
AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams) toolbar.getLayoutParams();
params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL|AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS);
toolbar.setLayoutParams(params);
Hold a reference to the layout params if you are changing instead of getting it all the time.
If you need to have the CollapsingToolbarLayout get from and set the LayoutParams to that View instead, update the flags the same way but now adding the appBarLayout.setExpanded(true/false)
Note: Using the setScrollFlags clears all previous flags, so be careful and set all required flags when using this method.
As #Moinkhan points out, you could try wrapping the RecyclerView and next elements in a NestedScrollView like this, this should resolve your problem of scrolling alongside with your collapsing toolbar layout:
<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.example.user.myapplication.ScrollingActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar"
android:layout_width="match_parent"
android:layout_height="#dimen/app_bar_height"
android:fitsSystemWindows="true"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/toolbar_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed|snap">
<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.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="fill_vertical"
android:fillViewport="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="#+id/nestedView"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</RelativeLayout>
</android.support.v4.widget.NestedScrollView>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_anchor="#id/app_bar"
app:layout_anchorGravity="bottom|end">
<Button
android:id="#+id/disableNestedScrollingButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="disable"/>
<Button
android:id="#+id/enableNestedScrollingButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="enable"
/>
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
In case the contents of the recyclerview are not displayed you can follow this thread to solve that issue How to use RecyclerView inside NestedScrollView?.
Hope it helps.
inside the recycler view, to scrolling smooth
android:nestedScrollingEnabled="false"
to overlap the cardView in the toolbar
app:behavior_overlapTop = "24dp"
Try this code for CollapsingToolbar:
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/background"
android:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar"
android:layout_width="match_parent"
android:layout_height="#dimen/app_bar_height"
android:fitsSystemWindows="true"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/toolbar_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<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"
app:title="Title" />
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:background="#android:color/transparent"
app:behavior_overlapTop="#dimen/behavior_overlap_top"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<LinearLayout
android:id="#+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler_view
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="#dimen/text_min_padding"
android:nestedScrollingEnabled="false"
android:scrollbarSize="2dp"
android:scrollbarStyle="outsideInset"
android:scrollbarThumbVertical="#color/colorAccent"
android:scrollbars="vertical" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
Screenshot
I had to solve a similar issue and did it using a custom behaviour on the AppBarLayout. Everything works great.
By overriding onStartNestedScroll in the custom behaviour it is possible to block to collapsing toolbar layout from expanding or collapsing while keeping the scroll view (NestedScrollView) in my case, working as expected. I explained the details here, hope it helps.
private class AppBarLayoutBehavior : AppBarLayout.Behavior() {
var canDrag = true
var acceptsNestedScroll = true
init {
setDragCallback(object : AppBarLayout.Behavior.DragCallback() {
override fun canDrag(appBarLayout: AppBarLayout): Boolean {
// Allow/Do not allow dragging down/up to expand/collapse the layout
return canDrag
}
})
}
override fun onStartNestedScroll(parent: CoordinatorLayout,
child: AppBarLayout,
directTargetChild: View,
target: View,
nestedScrollAxes: Int,
type: Int): Boolean {
// Refuse/Accept any nested scroll event
return acceptsNestedScroll
}}
Use following code, it works fine for me:
lockAppBarClosed();
ViewCompat.setNestedScrollingEnabled(recyclerView, false); // to lock the CollapsingToolbarLayout
and implement the following methods:
private void setAppBarDragging(final boolean isEnabled) {
CoordinatorLayout.LayoutParams params =
(CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
AppBarLayout.Behavior behavior = new AppBarLayout.Behavior();
behavior.setDragCallback(new AppBarLayout.Behavior.DragCallback() {
#Override
public boolean canDrag(AppBarLayout appBarLayout) {
return isEnabled;
}
});
params.setBehavior(behavior);
}
public void unlockAppBarOpen() {
appBarLayout.setExpanded(true, false);
appBarLayout.setActivated(true);
setAppBarDragging(false);
}
public void lockAppBarClosed() {
appBarLayout.setExpanded(false, false);
appBarLayout.setActivated(false);
setAppBarDragging(false);
}
I believe that this problem is related to the collapsing toolbar snapping into place (either closed or open) and leaving a vertical offset variable (mScrollOffset[1] in RecyclerView) with a non-zero value that subsequently biases the scroll - slowing or reversing the scroll in one direction and speeding it up in the other. This variable only seems to be set in NestedScrollingChildHelper if nested scrolling is enabled. So, whatever value mScrollOffset[1] has goes unchanged once nest scrolling is disabled.
To reliably reproduce this issue, you can cause the toolbar to snap into place then immediately click disable. See this video for a demonstration. I believe, that the magnitude of the issue varies by how much "snapping" occurs.
If I drag the toolbar to the fully open or closed position and don't let it "snap", then I have not been able to reproduce this problem and mScrollOffset[1] is set to zero which I think is the right value. I have also reproduced the problem by removing snap from the layout_scrollFlags of the collapsing toolbar in the layout and placing the toolbar in a partially open state.
If you want to play around with this, you can put your demo app into debug mode and observe the value of mScrollOffset[1] in RecyclerView#onTouchEvent. Also take a look at NestedScrollingChildHelper's dispatchNestedScroll and dispatchNestedPreScroll methods to see how the offset is set only when nested scrolling is enabled.
So, how to fix this? mScrollOffset is private toRecyclerView and it is not immediately obvious how to subclass anything to change the value of mScrollOffset[1]. That would leave Reflection, but that may not be desirable to you. Maybe another reader has an idea about how to approach this or knows of some secret sauce. I will repost if anything occurs to me.
Edit: I have provided a new ScrollingActivity.java class that overcomes this issue. It does use reflection and applies a patch to set mScrollOffset[1] of RecyclerView to zero when the disable scroll button has been pressed and the AppBar is idle. I have done some preliminary testing and it is working. Here is the gist. (See updated gist below.)
Second edit: I was able to get the toolbar to snap in funny ways and get stuck in the middle without the patch, so it doesn't look like the patch is causing that particular issue. I can get the toolbar to bounce from fully open to collapsed by scrolling down fast enough in the unpatched app.
I also took another look at what the patch is doing and I think that it will behave itself: The variable is private and referred to only in one place after scrolling is turned off. With scrolling enabled, the variable is always reset before use. The real answer is for Google to fix this problem. Until they do, I think this may be the closest you can get to an acceptable work-around with this particular design. (I have posted an updated gist that addresses potential issues with a quick click-around leaving switches in a potential unsuitable state.)
Regardless, the underlying issue has been identified and you have a reliable way to reproduce the problem, so you can more easily verify other proposed solutions.
I hope this helps.
I want to present a nice alternative, mainly based on the one here :
AppBarLayoutEx.kt
class AppBarLayoutEx : AppBarLayout {
private var isAppBarExpanded = true
private val behavior = AppBarLayoutBehavior()
private var onStateChangedListener: (Boolean) -> Unit = {}
var enableExpandAndCollapseByDraggingToolbar: Boolean
get() = behavior.canDrag
set(value) {
behavior.canDrag = value
}
var enableExpandAndCollapseByDraggingContent: Boolean
get() = behavior.acceptsNestedScroll
set(value) {
behavior.acceptsNestedScroll = value
}
constructor(context: Context) : super(context)
constructor(context: Context, attrs: AttributeSet) : super(context, attrs)
init {
addOnOffsetChangedListener(
AppBarLayout.OnOffsetChangedListener { _, verticalOffset ->
isAppBarExpanded = verticalOffset == 0
onStateChangedListener(isAppBarExpanded)
})
}
override fun setLayoutParams(params: ViewGroup.LayoutParams?) {
super.setLayoutParams(params)
(params as CoordinatorLayout.LayoutParams).behavior = behavior
}
fun toggleExpandedState() {
setExpanded(!isAppBarExpanded, true)
}
fun setOnExpandAndCollapseListener(onStateChangedListener: (Boolean) -> Unit) {
this.onStateChangedListener = onStateChangedListener
}
private class AppBarLayoutBehavior : AppBarLayout.Behavior() {
var canDrag = true
var acceptsNestedScroll = true
init {
setDragCallback(object : AppBarLayout.Behavior.DragCallback() {
override fun canDrag(appBarLayout: AppBarLayout) = canDrag
})
}
override fun onStartNestedScroll(parent: CoordinatorLayout, child: AppBarLayout, directTargetChild: View,
target: View, nestedScrollAxes: Int, type: Int) = acceptsNestedScroll
}
}
Usage: besides using it in the layout XML file, you can disable/enable the expanding of it using:
appBarLayout.enableExpandAndCollapseByDraggingToolbar = true/false
appBarLayout.enableExpandAndCollapseByDraggingContent = true/false
I'm working on a project in which I want to use the Circular Reveal effect as per the Material Design. Project has minSDK = 11, so for compatibility with pre-Lollipop devices, I'm using this library https://github.com/ozodrukh/CircularReveal
I've a fragment with a FloatingActionButton that, when tapped, will transform itself in the CardView, like described here FAB transformations.
Once the card is revealed it has a button to revert the animation, re-transforming the card into the FAB. Now my problem is this: let's say that a user tap the FAB and the CardView is revealed. Now the user rotate his device, so the activity resets the fragment. What I want to achieve is the card stay visible and revealed, while the FAB should be disabled and invisible. The problem is that if I simply use setVisibility(View.INVISIBLE) on my FAB it doesn't work (note that if I use getVisibility() on it just after setting it invisible, it correctly returns me the value 4 == View.INVISIBLE, but the fab is still visible). I've to wrap the setVisibility(...) call inside a postDelayed() with at least 50-100 ms of delay to make the fab invisible.
So my question is: am I doing things right or there's a better way to accomplish what I want (because it seems very ugly to me)?
Here's some code. This is my XML layout of the fragment:
<android.support.design.widget.CoordinatorLayout
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">
<android.support.design.widget.AppBarLayout
android:id="#+id/my_appbar"
android:layout_width="match_parent"
android:layout_height="#dimen/toolbar_expanded_height"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.CollapsingToolbarLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:expandedTitleMarginEnd="64dp"
app:expandedTitleMarginStart="70dp"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<android.support.v7.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:popupTheme="#style/ToolbarPopupTheme"
app:layout_collapseMode="pin"/>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
...
<io.codetail.widget.RevealFrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<include layout="#layout/my_fragment" />
</io.codetail.widget.RevealFrameLayout>
<android.support.design.widget.FloatingActionButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="#dimen/fab_margin"
app:fabSize="mini"
app:layout_anchor="#+id/my_appbar"
app:layout_anchorGravity="bottom|left|start" />
</android.support.design.widget.CoordinatorLayout>
This is the XML layout of the included CardView:
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:layout_gravity="center"
card_view:cardCornerRadius="2dp"
android:visibility="invisible"
android:focusableInTouchMode="true">
<RelativeLayout android:layout_width="match_parent"
android:layout_height="match_parent">
...
<LinearLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="end">
<Button android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="Ok" />
<Button android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Cancel" />
</LinearLayout>
</RelativeLayout>
</android.support.v7.widget.CardView>
And this is the code of my Fragment:
public class MyFragment extends Fragment {
private static final String CARD_OPEN_TAG = "CARD_OPEN_TAG";
public static MyFragment newInstance(){
return new MyFragment();
}
private int cardOpen;
private FloatingActionButton fabAddPublication;
private CardView card;
private Button cardCancel;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View rootView = inflater.inflate(R.layout.fragment_magazines, container, false);
toolbar = (Toolbar) rootView.findViewById(R.id.layout);
...
// Initialize view status
if (savedInstanceState != null){
cardOpen = savedInstanceState.getInt(CARD_OPEN_TAG);
} else {
cardOpen = -1;
}
...
// Get FAB reference
fab = (FloatingActionButton) rootView.findViewById(R.id.fab_id);
// Get card reference
card = (CardView) rootView.findViewById(R.id.card_id);
editorPublication.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
// Using this event because I need my card to be measured to move correctly fab at his center
if (cardOpen != -1){
// Move FAB to center of card
fab.setTranslationX(coordX); // WORKS
fab.setTranslationY(coordY); // WORKS
// fab.setVisibility(View.INVISIBLE) -> DOESN'T WORK, fab remain visible on top and at center of my card
// Ugly workaround
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
// Hide FAB
fab.setVisibility(View.INVISIBLE);
}
}, 50); // Sometimes fails: if device/emulator use too much time to "rotate" screen, fab stay visible
// Remove listener
ViewTreeObserver obs = card.getViewTreeObserver();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
obs.removeOnGlobalLayoutListener(this);
else obs.removeGlobalOnLayoutListener(this);
}
}
});
if (editorOpen != -1){
fab.setEnabled(false); // WORKS
card.setVisibility(View.VISIBLE); // WORKS
}
// Get editors buttons reference
cardCancel = (Button) card.findViewById(R.id.card_cancel_id);
// Set FAB listener
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Explode FAB
explodeFab(fab, card); // This method trigger the reveal animation
cardOpen = card.getId();
}
});
// Set editors button listeners
cardCancel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Implode FAB
implodeFAB(fab, card); // This card reverts the reveal animation
cardOpen = -1;
}
});
...
return rootView;
}
#Override
public void onSaveInstanceState(Bundle outState){
super.onSaveInstanceState(outState);
...
outState.putInt(CARD_OPEN_TAG, cardOpen);
}
}
I don't think that what you're doing is correct and here's why:
1.
That circular reveal library you're using is incompatible with hardware acceleration on Android 11 to 17 (3.0 to 4.2). It's using Canvas.clipPath() - a method which was implemented in software only up to Android 4.3. It means that you have to turn hardware acceleration off or your app will crash on not supported OpenGL call.
The best way to clip layouts is to use Canvas.saveLayer()/restoreLayer(). It's the only way to support all devices, get antialiased image and support invalidate/layout/draw flow correctly.
2.
Relying on timers and layout listeners to change layouts means that something is not really working for you. Each change can be executed directly without waiting. You just have to find the right place for that piece of code.
Timers can also trigger when your app is in background. It means that it will crash while trying to access UI from Timer thread.
Maybe you're calling setVisibility(true) somewhere in the code and that's why your FAB is visible? Setting visibility is ok and should work without any delayed calls. Just save visibility as FAB's state and restore it after orientation change.
If you wish to position the FAB at the center of the toolbar, wrap them both in a FrameLayout (wrap_content) and position the FAB with layout_gravity="center". That should allow you to remove layout listener.
3.
support.CardView is broken and shouldn't be used at all. It looks and works a little bit different on Lollipop and on older systems. The shadow is different, the padding is different, content clipping doesn't work on pre-Lollipop devices, etc. That's why it's hard to get consistent, good results on all platforms.
You should consider using plain layouts for that purpose.
4.
Some animations are cool-looking, but hard to implement, doesn't give any value and quickly become irritating, because the user has to wait for the animation to finish each time he/she clicks the button.
I'm not saying no for your case, but you may consider removing the transformation and using a drop down menu, a bottom sheet, a static toolbar or a dialog for that purpose.
I'm looking for a solution to this that will allow me to expand a cardview to see more information and then easily collapse it. Google Keep has examples of cards like this. Anyone know how they do this? Would I create 2 versions of my cardview (one collapsed and one expanded) and then use an Animator class coupled with gesture methods to transition between the two views? I'm using a Recyclerview to hold my cardviews.
I found this if it is at all relevant: http://developer.android.com/training/animation/layout.html
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:orientation="vertical"
android:animateLayoutChanges="true"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
//here put the view which is always visible
<LinearLayout
android:layout_width="match_parent"
android:visibilty="gone"
android:id="#+id/expandableLayout"
android:layout_height="wrap_content">
//here put which will collapse and expand
</LinearLayout>
</android.support.v7.widget.CardView>
take a boolean isexpanded in you arraylist object class
if (listobj.isexpanded)
{
holder.expandableLayout.setVisibility(View.VISIBLE);
}
else {
holder.expandableLayout.setVisibility(View.GONE);
}
holder.cardView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (listobj.isexpanded)
{
holder.expandableLayout.setVisibility(View.GONE);
listobj.isexpanded=false;
notifyItemChanged(position);
}
else {
holder.expandableLayout.setVisibility(View.VISIBLE);
listobj.isexpanded=true;
notifyItemChanged(position);
}
}
});
try someting like this
I am new in Android animation and my requirement is to translate a view from one layout to layout in a single xml file on click of that view.
Scenario:
Suppose I click a button, present on the top of the header in a xml file,and it should move/translate downwards (it should give an impact that it lies on the other layout downwards to header), and also I want that when the user clicks on the same again, it should now move to its original position.
Here I am explaining with my xml file:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/app_bg"
android:orientation="vertical" >
<RelativeLayout
android:id="#+id/top"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/header"
android:paddingLeft="10dp"
android:paddingRight="10dp" >
<Button
android:id="#+id/btnSearchHeader"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerInParent="true"
android:background="#drawable/search_icon" />
</RelativeLayout>
<RelativeLayout
android:id="#+id/bottom"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/app_transparent"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:layout_marginTop="10dp"
android:visibility="visible" >
<Button
android:id="#+id/btnMenu"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:layout_marginRight="5dp"
android:text="ABC" />
<Button
android:id="#+id/btnSearchSelected"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toRightOf="#+id/btnMenu"
android:text="CDE" />
</RelativeLayout>
</LinearLayout>
MORE PRECISE REQUIREMENT SPECIFICATION (Kindly read carefully:)
Here I have two sub inner layouts:-
Top Layout - id-> top
Bottom Layout- id -> bottom
Now a view (Button -> btnSearchHeader) is lying in my top layout and I want to animate the same to the bottom layout (it should give an impact that it is translated with a translate animation to the bottom layout) on click of that button and when the user clicks on that button, it should again translate back to its original position with a translate animation .. i.e it should show back in the top layout
I have no idea how to give these impacts using translate animations, however i just have a basic translate animation knowledge which is insufficient for me to work upon my requirement.
Any type of related help is appreciable.
Thanks
Have you tried something simple like the following?
final int topHeight = findViewById(R.id.top).getHeight();
final int bottomHeight = findViewById(R.id.bottom).getHeight();
final View button = findViewById(R.id.btnSearchHeader);
final ObjectAnimator moveDownAnim = ObjectAnimator.ofFloat(button, "translationY", 0.F, topHeight + bottomHeight / 2 - button.getHeight() / 2);
final ObjectAnimator moveUpAnim = ObjectAnimator.ofFloat(button, "translationY", topHeight + bottomHeight / 2 - button.getHeight() / 2, 0.F);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (0.F == v.getTranslationY())
moveDownAnim.start();
else
moveUpAnim.start();
}
});
If you actually need the button view to change parents, you can use AnimatorListener to achieve this at the end of each animation. Something like:
moveDownAnim.addListener(new Animator.AnimatorListener() {
#Override
public void onAnimationEnd(Animator animation) {
((ViewGroup)findViewById(R.id.top)).removeView(button);
((ViewGroup)findViewById(R.id.bottom)).addView(button);
((RelativeLayout)button.getLayoutParams()).addRule(RelativeLayout.CENTER_IN_PARENT);
button.setTranslationY(0.F); // Since it is now positioned in the new layout, no need for translation.
}
#Override
public void onAnimationCancel(Animator animation) { /* NOP */ }
#Override
public void onAnimationRepeat(Animator animation) { /* NOP */ }
#Override
public void onAnimationStart(Animator animation) { /* NOP */ }
});
(And analogous listener for the moveUpAnim.)
However, I doubt you need to actually do this to achieve the visual effect you want. But if you do this part, you will probably also need to set a fixed height for your top view as opposed to wrap_content. (Otherwise, if a layout pass happens while the button has been moved to the bottom view, the top layout's height might go to 0 if there's nothing else in it.) Easiest would be to just do this directly in the xml layout file. However, if you want to "do it on the fly", you can change the layout's height in the onAnimationEnd() method using something like:
#Override
public void onAnimationEnd(Animator animation) {
final ViewGroup topLayout = findViewById(R.id.top);
topLayout.getLayoutParams().height = topLayout.getHeight(); // Keep it the same height...
topLayout.removeView(button);
((ViewGroup)findViewById(R.id.bottom)).addView(button);
((RelativeLayout)button.getLayoutParams()).addRule(RelativeLayout.CENTER_IN_PARENT);
button.setTranslationY(0.F); // Since it is now positioned in the new layout, no need for translation.
}