Develop Reference

Bugged BottomSheet which is shown when not required

I have a BottomSheet in my App whic have to be shown ONLY at the BottomAppBar navigation button click.
The issue is that in my BottomAppBar i have a FAB button which handles a long click which shows a View and a FAB menu,
when long clicked it make even the BottomSheet expanded when there is no code for it!
Here is my BottomSheet:
<LinearLayout
android:id="#+id/bottomSheet"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
app:behavior_hideable="true"
android:elevation="8dp"
android:clickable="true"
android:focusable="true"
app:behavior_peekHeight="0dp"
app:layout_behavior="#string/bottom_sheet_behavior">
<include layout="#layout/bottom_sheet" />
</LinearLayout>
Here is the only click where i make it EXPANDED_HALF:
bottomAppBar.setNavigationOnClickListener {
bottomSheetBehavior.state = BottomSheetBehavior.STATE_HALF_EXPANDED
}
And here is my longClick which make it fully expanded:
fabNuovo.setOnLongClickListener {
if (View.GONE == fabBGLayout.visibility) {
showFAB()
}else {
closeFAB()
}
}
private fun showFAB() {
fabNuovo.setImageDrawable(ContextCompat.getDrawable(this#LetturaActivity,R.drawable.ic_baseline_close_24))
fabSend.visibility = View.VISIBLE
fabBGLayout.visibility = View.VISIBLE
fabSend.animate().translationY(-120F)
}
private fun closeFAB() {
fabNuovo.setImageDrawable(ContextCompat.getDrawable(this#LetturaActivity,R.drawable.ic_baseline_done_24))
fabBGLayout.visibility = View.GONE
fabSend.visibility = View.GONE
fabSend.animate().translationY(0f)
}
EDIT:
It's not expanded for really as it doesn't cast any callback in BottomSheetCallback...
And even if i click to dismiss the FAB menu it's expanded if not and collapsed if expanded...
EDIT2:
The issue is surely given from one of the following lines in showFAB and closeFAB:
fabSend.visibility = View.VISIBLE
fabBGLayout.visibility = View.VISIBLE
fabSend.animate().translationY(-120F)

Viewpager2 inside Nestedscrollview consist two Fragment with Recyclerview having problem

I made a viewpager2 which has two Fragments, inside each Fragment there is a Recyclerview. The viewpager itself is inside a Nestedscrollview in order to hide the toolbar when scroll up. Here is my code:
<?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"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/appbarlayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#color/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways">
</androidx.appcompat.widget.Toolbar>
<com.google.android.material.tabs.TabLayout
android:id="#+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAlignment="center"
app:tabGravity="fill"
app:tabMode="fixed"/>
</com.google.android.material.appbar.AppBarLayout>
<androidx.core.widget.NestedScrollView
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.viewpager2.widget.ViewPager2
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"/>
</LinearLayout>
</androidx.core.widget.NestedScrollView>
<include layout="#layout/material_design_floating_action_menu" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
As I said the viewPager2 have two fragment each of them have a recyclerview. Here problem is, fragment 2 recyclerView take the same height of fragment 1 recyclerView though both recyclerView have different list items and their height should be depends on the list items. I mean, I am expecting these recyclerViews height should act separately based on the list. How can I solve this issue? Please let me know if you need fragment code.
Edit:
Activity code which holds the viewPager2
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initToolbar();
init();
viewPager.setAdapter(createCardAdapter());
new TabLayoutMediator(tabLayout, viewPager,
new TabLayoutMediator.TabConfigurationStrategy() {
#Override public void onConfigureTab(#NonNull TabLayout.Tab tab, int position) {
//tab.setText("Tab " + (position + 1));
if(position == 0){
tab.setText("Home");
}else if(position == 1){
tab.setText("Events");
}
}
}).attach();
RunnTimePermissions.requestForAllRuntimePermissions(this);
showNotifyDialog();
}
ViewPager Adapter Code:
public class ViewPagerAdapter extends FragmentStateAdapter {
private static final int CARD_ITEM_SIZE = 2;
public ViewPagerAdapter(#NonNull FragmentActivity fragmentActivity) {
super(fragmentActivity);
}
#NonNull #Override public Fragment createFragment(int position) {
switch (position){
case 0:
return HomeFragment.newInstance("abc","abc");
// break;
case 1:
return EventListFragment.newInstance("abc","abc");
// break;
}
return HomeFragment.newInstance("abc","abc");
}
#Override public int getItemCount() {
return CARD_ITEM_SIZE;
}
}
Fragment 1 layout:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".fragment.EventListFragment">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rv_event_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:layout_marginTop="16dp"
/>
</FrameLayout>
Fragment 2 layout
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".fragment.MedicineListFragment">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rv_medicine_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:layout_marginTop="16dp"
/>
</FrameLayout>

Alright buddy. I did it! I have the solution to this issue.
First off, here's the official response from Google after I opened an issue.
https://issuetracker.google.com/issues/188474850?pli=1
Anyway, on to the fix. Replace the NestedScrollView with this class:
https://gist.github.com/AfzalivE/fdce03eeee8e16203bcc37ba26d7abf3
The idea is to basically create a very light-weight version of NestedScrollView. Instead of messing with child heights, we listen to the children's scroll and either let them scroll, or forward the scrolling to the BottomSheetBehavior. For example when the RecyclerView has been scrolled all the way to the top, then it doesn't consume any of the scrolling, so we can forward that to the bottom sheet so it can scroll. And we only allow the RecyclerView to scroll when the Bottom sheet is expanded.
Also, I must add that this scenario works out of the box with Jetpack Compose + Accompanist-pager so just do that if you really need perfect functionality.
class BottomSheetScrollView(context: Context, attrs: AttributeSet?) : FrameLayout(context, attrs),
NestedScrollingParent2 {
private val TAG = "NestedScroll3"
private val childHelper = NestedScrollingChildHelper(this).apply {
isNestedScrollingEnabled = true
}
private var behavior: BottomSheetBehavior<*>? = null
var started = false
var canScroll = false
var pendingCanScroll = false
var dyPreScroll = 0
init {
ViewCompat.setNestedScrollingEnabled(this, true)
}
private val bottomSheetCallback = object : BottomSheetBehavior.BottomSheetCallback() {
override fun onStateChanged(bottomSheet: View, newState: Int) {
onNextScrollStop(newState == BottomSheetBehavior.STATE_EXPANDED)
Log.d(
"BottomSheet",
"Can scroll CHANGED to: $canScroll, because bottom sheet state is ${
getBottomSheetStateString(newState)
}"
)
}
override fun onSlide(bottomSheet: View, slideOffset: Float) = Unit
}
fun onNextScrollStop(canScroll: Boolean) {
pendingCanScroll = canScroll
}
override fun onStartNestedScroll(child: View, target: View, axes: Int, type: Int): Boolean {
// ViewPager2's RecyclerView does not participate in this nested scrolling.
// This allows it to show it's overscroll indicator.
if (target is RecyclerView) {
val layoutManager = target.layoutManager as LinearLayoutManager
if (layoutManager.orientation == LinearLayoutManager.HORIZONTAL) {
target.isNestedScrollingEnabled = false
}
}
if (!started) {
Log.d(TAG, "started nested scroll from $target")
childHelper.startNestedScroll(axes, type)
started = true
}
return true
}
override fun onNestedScrollAccepted(child: View, target: View, axes: Int, type: Int) {
Log.d(TAG, "accepted nested scroll from $target")
}
override fun onStopNestedScroll(target: View, type: Int) {
if (started) {
childHelper.stopNestedScroll(type)
started = false
Log.d(
TAG,
"stopped nested scroll from $target, changing canScroll from $canScroll to $pendingCanScroll"
)
canScroll = pendingCanScroll
}
}
override fun onNestedScroll(
target: View,
dxConsumed: Int,
dyConsumed: Int,
dxUnconsumed: Int,
dyUnconsumed: Int,
type: Int
) {
Log.d(
TAG,
"onNestedScroll: dxC: $dxConsumed, dyC: $dyConsumed, dxU: $dxUnconsumed, dyU: $dyUnconsumed"
)
if (dyUnconsumed == dyPreScroll && dyPreScroll < 0) {
canScroll = false
Log.d(TAG, "Can scroll CHANGED to: $canScroll, because scrolled to the top of the list")
}
}
override fun onNestedPreScroll(target: View, dx: Int, dy: Int, consumed: IntArray, type: Int) {
Log.d(
TAG,
"onNestedPreScroll: dx: $dx, dy: $dy, consumed: [ ${consumed.joinToString(", ")} ]"
)
if (!canScroll) {
childHelper.dispatchNestedPreScroll(dx, dy, consumed, null, type)
// Ensure all dy is consumed to prevent premature scrolling when not allowed.
consumed[1] = dy
} else {
dyPreScroll = dy
}
}
override fun onAttachedToWindow() {
super.onAttachedToWindow()
behavior = findBottomSheetBehaviorParent(parent) as BottomSheetBehavior<*>?
behavior?.addBottomSheetCallback(bottomSheetCallback)
}
override fun onDetachedFromWindow() {
super.onDetachedFromWindow()
behavior?.removeBottomSheetCallback(bottomSheetCallback)
}
private fun findBottomSheetBehaviorParent(parent: ViewParent?): CoordinatorLayout.Behavior<*>? {
if (parent !is View) {
throw IllegalArgumentException(
"None of this view's ancestors are associated with BottomSheetBehavior"
)
}
val layoutParams = parent.layoutParams
return if (layoutParams is CoordinatorLayout.LayoutParams && layoutParams.behavior != null) {
layoutParams.behavior
} else {
findBottomSheetBehaviorParent((parent as View).parent)
}
}
private fun getBottomSheetStateString(state: Int): String {
return when (state) {
1 -> "STATE_DRAGGING"
2 -> "STATE_SETTLING"
3 -> "STATE_EXPANDED"
4 -> "STATE_COLLAPSED"
5 -> "STATE_HIDDEN"
6 -> "STATE_HALF_EXPANDED"
else -> "0"
}
}
}

I do not understand why you have recyclerview inside FrameLayout .
Here problem is, fragment 2 recyclerView take the same height of
fragment 1 recyclerView though both recyclerView have different list
items and their height should be depends on the list items
RecyclerView generally always depends on the item_layout until we have not fixed its height n width to match_parent.
In your case you have fixed RecyclerView android:layout_width and android:layout_width to match_parent in both the Fragment .
Try this:
Fragment 1
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".fragment.EventListFragment">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rv_event_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
/>
</FrameLayout>
Fragment 2
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".fragment.MedicineListFragment">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rv_medicine_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
/>
</FrameLayout>
P.S: assuming each reacyclerView's item_layout would be having height as wrap_content

How do I achieve on scroll behavior where both the toolbar and bottom navigation should hide?Only one of them is working

I am trying to achieve the coordinator layout behaviour where on scrolling the recycler view can hide both the toolbar and bottom navigation view. So far I have achieved one success i.e bottom navigation bottom bar does hide but with one caveat that it remains active even when the keyboard is on(how do I fix that too?)
My main concern here is how do I achieve the same feature of bottom navigation view of hiding into the toolbar?
I have included the custom toolbar in Appbar layout, but I have tried to add the Toolbar layout tag too in the AppBar nothing works, It just remains the same.
And for the bottomnavigation jumping up on top I don't know what to do? till now I have added snap scroll flags on the bottomnavigation view to stop this behaviour and also snap flag didn't work, I think so, coz it remains in halfway position while going up on search tap.
Got this BottomNavigationBehavior from the wonderful article.
reference
video showing behavior
image for snap behavior
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
>
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="?actionBarSize"
app:elevation="0dp"
android:background="#android:color/transparent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
>
<include
app:layout_scrollFlags="scroll|enterAlways|snap"
layout="#layout/browser_search_tap_tb"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/browser_tb"
/>
</com.google.android.material.appbar.AppBarLayout>
<!--Scrolling effect for the bottom nav menu-->
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:listitem="#layout/rv_test_items"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:id="#+id/rv_test"
/>
<!--Bottom navigation view for the Selection of the Tabs and Items in Menu-->
<com.google.android.material.bottomnavigation.BottomNavigationView
app:layout_scrollFlags="scroll|enterAlways|snap"
android:id="#+id/browser_bottom_nav_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="#ffff"
app:layout_behavior="com.example.android.browserui.BottomNavigationBehavior"
app:labelVisibilityMode="unlabeled"
app:menu="#menu/bottom_nav_menu"
/>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
browser_search_tap_tb.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.Toolbar
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="?actionBarSize"
android:background="#android:color/transparent"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat"
app:contentInsetStart="8dp"
app:contentInsetEnd="8dp"
>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:layout_width="0dp"
android:layout_height="match_parent"
android:hint="Search or type new address"
android:padding="8dp"
android:paddingEnd="12dp"
android:paddingStart="12dp"
android:drawableEnd="#drawable/ic_mic"
android:inputType="textWebEditText"
android:background="#drawable/rounded_et_search"
app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent" android:id="#+id/et_search_bar_tap"
app:layout_constraintEnd_toEndOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.appcompat.widget.Toolbar>
BottomNavigationBehavior.kt
class BottomNavigationBehavior<V : View>(context: Context, attrs: AttributeSet) :
CoordinatorLayout.Behavior<V>(context, attrs) {
private var lastStartedType: Int = 0
private var offsetAnimator: ValueAnimator? = null
var isSnappingEnabled = false
override fun layoutDependsOn(parent: CoordinatorLayout, child: V, dependency: View): Boolean {
if (dependency is Snackbar.SnackbarLayout) {
updateSnackbar(child, dependency)
}
return super.layoutDependsOn(parent, child, dependency)
}
override fun onStartNestedScroll(
coordinatorLayout: CoordinatorLayout, child: V, directTargetChild: View, target: View, axes: Int, type: Int
): Boolean {
if (axes != ViewCompat.SCROLL_AXIS_VERTICAL)
return false
lastStartedType = type
offsetAnimator?.cancel()
return true
}
override fun onNestedPreScroll(
coordinatorLayout: CoordinatorLayout, child: V, target: View, dx: Int, dy: Int, consumed: IntArray, type: Int
) {
super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type)
child.translationY = max(0f, min(child.height.toFloat(), child.translationY + dy))
}
override fun onStopNestedScroll(coordinatorLayout: CoordinatorLayout, child: V, target: View, type: Int) {
if (!isSnappingEnabled)
return
// add snap behaviour
// Logic here borrowed from AppBarLayout onStopNestedScroll code
if (lastStartedType == ViewCompat.TYPE_TOUCH || type == ViewCompat.TYPE_NON_TOUCH) {
// find nearest seam
val currTranslation = child.translationY
val childHalfHeight = child.height * 0.5f
// translate down
if (currTranslation >= childHalfHeight) {
animateBarVisibility(child, isVisible = false)
}
// translate up
else {
animateBarVisibility(child, isVisible = true)
}
}
}
private fun animateBarVisibility(child: View, isVisible: Boolean) {
if (offsetAnimator == null) {
offsetAnimator = ValueAnimator().apply {
interpolator = DecelerateInterpolator()
duration = 150L
}
offsetAnimator?.addUpdateListener {
child.translationY = it.animatedValue as Float
}
} else {
offsetAnimator?.cancel()
}
val targetTranslation = if (isVisible) 0f else child.height.toFloat()
offsetAnimator?.setFloatValues(child.translationY, targetTranslation)
offsetAnimator?.start()
}
private fun updateSnackbar(child: View, snackbarLayout: Snackbar.SnackbarLayout) {
if (snackbarLayout.layoutParams is CoordinatorLayout.LayoutParams) {
val params = snackbarLayout.layoutParams as CoordinatorLayout.LayoutParams
params.anchorId = child.id
params.anchorGravity = Gravity.TOP
params.gravity = Gravity.TOP
snackbarLayout.layoutParams = params
}
}
}

So Finally Resolved My issue after getting my head around for 4 days here are some changes which I did and solved the issues :
activity_main.xml
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="?actionBarSize"
app:elevation="0dp"
android:background="#android:color/transparent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"<!--Removed this line-->
>
<!--Bottom navigation view for the Selection of the Tabs and Items in Menu-->
<com.google.android.material.bottomnavigation.BottomNavigationView
app:layout_scrollFlags="scroll|enterAlways|snap"<!--Removed this line-->
android:id="#+id/browser_bottom_nav_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="#ffff"
app:layout_behavior="com.example.android.browserui.BottomNavigationBehavior"
app:labelVisibilityMode="unlabeled"
app:menu="#menu/bottom_nav_menu"
/>
Here in activity_main.xml, I removed the layout_behavior because the appbar itself is invoking the scroll behavior for other layout items, it acts as a parent.
app:layout_behavior="#string/appbar_scrolling_view_behavior"
Also removed scrollflags from the bottom navigation view, AS I was implementing this behavior from the Class BottomNavigationBehavior.kt, You find the implementation below
app:layout_scrollFlags="scroll|enterAlways|snap"
browser_search_tap_tb.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.Toolbar
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="?actionBarSize"
android:background="#android:color/transparent"
app:layout_scrollFlags="scroll|enterAlways" <!--Removed this line-->
app:popupTheme="#style/ThemeOverlay.AppCompat"
app:contentInsetStart="8dp"
app:contentInsetEnd="8dp"
>
Here in browser_search_tb, I removed the following line because it was overriding the Scrollflags in co-ordinator layout so removed it and it worked flawlessly
app:layout_scrollFlags="scroll|enterAlways"
BottomNavigationBehavior.kt
override fun onStopNestedScroll(coordinatorLayout: CoordinatorLayout, child: V, target: View, type: Int) {
if (!isSnappingEnabled)
return // removed this line
{
// add snap behaviour
// Logic here borrowed from AppBarLayout onStopNestedScroll code
if (lastStartedType == ViewCompat.TYPE_TOUCH || type == ViewCompat.TYPE_NON_TOUCH) {
// find nearest seam
val currTranslation = child.translationY
val childHalfHeight = child.height * 0.5f
// translate down
if (currTranslation >= childHalfHeight) {
animateBarVisibility(child, isVisible = false)
}
// translate up
else {
animateBarVisibility(child, isVisible = true)
}
}
}
}
Here I removed the
return
and added braces{} to the if statement and snap feature did work properly
Hope this answer will help you and will cut down your debugging time.
The above reference is one of the best article you can find for scrolling behavior on the internet it simple and smooth to grasp

How i can set Half Expanded state for my BottomSheet

I have layout with bottom sheet.
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/coordinator_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<com.google.android.material.appbar.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:contentScrim="#color/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed" />
</com.google.android.material.appbar.AppBarLayout>
<include layout="#layout/content_main_weather_map" />
<include layout="#layout/bottom_sheet" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
Bottom sheet layout
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView 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/bottom_sheet"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white"
android:clipToPadding="true"
app:behavior_peekHeight="80dp"
app:layout_behavior="#string/bottom_sheet_behavior">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/weather_recycler"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
tools:listitem="#layout/item_weather" />
</LinearLayout>
</androidx.core.widget.NestedScrollView>
It is necessary for me that my bottom sheet opens first half, and after re-dragging it opens to full screen. How is it done in google maps app. But I have no idea how to do this.

It is better to use the framework with its full potential. As official documentation states for method setFitToContents :
Sets whether the height of the expanded sheet is determined by the height of its contents, or if it is expanded in two stages (half the height of the parent
container, full height of parent container). Default value is true.
So all you need is set setFitToContent to false with:
behavior = BottomSheetBehavior.from(your_bottom_sheet_xml)
behavior.isFitToContents = false
behavior.halfExpandedRatio = 0.6f
With this 3-line-code the bottom sheet will expand till 60% of the screen at first, and afterwards it will fully expand to 100%.
Hope it helps!

Just set BottomSheetBehaivor state to BottomSheetBehavior.STATE_HALF_EXPANDED.
Also if you need after full expanding let user again go back to half expanded mode, you need to set peek height to half of window height.
val bottomSheetBehavior = BottomSheetBehavior.from<NestedScrollView>(bottom_sheet)
val metrics = resources.displayMetrics
bottomSheetBehavior.peekHeight = metrics.heightPixels / 2
bottomSheetBehavior.state = BottomSheetBehavior.STATE_HALF_EXPANDED

I have tried the #Massab and #HeyAlex but didn't match my desired behavior.
With the following solution in kotlin, if your bottomsheet sliding is near the expanded state, it stays expanded, if is near the half state, stays at half and if it's near collapsed, it stays collapsed:
val bottomSheet = view.findViewById<View>(R.id.bottom_sheet1)
val mBottomSheetBehavior = BottomSheetBehavior.from(bottomSheet)
mBottomSheetBehavior.state = BottomSheetBehavior.STATE_COLLAPSED
mBottomSheetBehavior.addBottomSheetCallback(object: BottomSheetBehavior.BottomSheetCallback(){
override fun onStateChanged(bottomSheet: View, newState: Int) {
}
override fun onSlide(bottomSheet: View, slideOffset: Float) {
val upperState = 0.66
val lowerState = 0.33
if (bottomSheetEventsFilterBehavior.state == BottomSheetBehavior.STATE_SETTLING ) {
if(slideOffset >= upperState){
mBottomSheetBehavior.state = BottomSheetBehavior.STATE_EXPANDED
}
if(slideOffset > lowerState && slideOffset < upperState){
mBottomSheetBehavior.state = BottomSheetBehavior.STATE_HALF_EXPANDED
}
if(slideOffset <= lowerState){
mBottomSheetBehavior.state = BottomSheetBehavior.STATE_COLLAPSED
}
}
}
})

Although this question has been answered, but just got another way to implement this behavior so sharing for others.
Create a global variable and initialize it with the default state of your BottomSheetBehavior, like
int state = BottomSheetBehavior.STATE_COLLAPSED;
Then, in BottomSheetBehavior.BottomSheetCallback update your state variable to the current state
and in
BottomSheetBehavior.STATE_DRAGGING, if state is not half expanded,
set the state to BottomSheetBehavior.STATE_HALF_EXPANDED
sheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
#Override
public void onStateChanged(#NonNull View view, int i) {
switch (i) {
case BottomSheetBehavior.STATE_COLLAPSED:
state = BottomSheetBehavior.STATE_COLLAPSED;
binder.imgRefresh.setVisibility(View.GONE);
break;
case BottomSheetBehavior.STATE_EXPANDED:
binder.imgRefresh.setVisibility(View.VISIBLE);
state = BottomSheetBehavior.STATE_EXPANDED;
break;
case BottomSheetBehavior.STATE_DRAGGING:
if (state != BottomSheetBehavior.STATE_HALF_EXPANDED) {
sheetBehavior.setState(BottomSheetBehavior.STATE_HALF_EXPANDED);
}
break;
case BottomSheetBehavior.STATE_HALF_EXPANDED:
state = BottomSheetBehavior.STATE_HALF_EXPANDED;
break;
}
}
#Override
public void onSlide(#NonNull View view, float v) {
binder.viewExtender.setAlpha(1 - v);
}
});
This will make your BottomSheet to take three steps , i.e., Collapsed, Half Expanded, Expanded.
Hope it can help someone!

class BottomSheetFragment : BottomSheetDialogFragment() {
/* inside of your Bottom Sheet Dialog Fragment */
override fun onStart() {
super.onStart()
BottomSheetBehavior.from(requireView().parent as View).apply {
state = BottomSheetBehavior.STATE_HALF_EXPANDED
}
}
}

Use this block in onCreateView before returning root view
dialog!!.setOnShowListener { dialog ->
val d = dialog as BottomSheetDialog
BottomSheetBehavior.from(requireView().parent as View).apply {
state = BottomSheetBehavior.STATE_EXPANDED
}
}

Expanding And Collapsing Toolbar In Android

I am implementing expanding and collapsing toolbar with the help of collapsing toolbar but I am stuck when my toolbar is collapsed I want to show different toolbar. I have seen so piece of code but cannot be able to find my solution.
I have also seen the solution of one of the amazing developer https://github.com/saulmm/CoordinatorLayoutExample but cannot be able to find out my solution properly
This is my piece of code which i have implemented
activity_collapsing_toolbar.xml
<?xml version="1.0" encoding="utf-8"?>
<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/app_bar_layout"
android:layout_width="match_parent"
android:layout_height="176dp"
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"
app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:background="#color/base_color_theme_new"
android:gravity="center_horizontal"
app:layout_collapseMode="parallax">
<RelativeLayout
android:id="#+id/rl_class_image"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="26dp"
android:gravity="center">
<LinearLayout
android:id="#+id/ll_class"
android:layout_width="60dp"
android:layout_height="60dp"
android:background="#drawable/rounded_white_circle"
android:gravity="center">
<ImageView
android:id="#+id/iv_class_image"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_gravity="center"
android:padding="8dp"
android:src="#drawable/class_4" />
</LinearLayout>
</RelativeLayout>
<TextView
android:id="#+id/tv_class_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#id/rl_class_image"
android:layout_marginTop="15dp"
android:gravity="center"
android:text="MATHEMATICS"
android:textSize="17sp" />
<TextView
android:id="#+id/tv_videos_test"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#id/tv_class_name"
android:layout_marginTop="10dp"
android:gravity="center"
android:text="20 VIDEOS | 5 TESTS"
android:textSize="10sp" />
</RelativeLayout>
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_collapseMode="pin" />
</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="#drawable/rounded_corners_for_list"
android:fillViewport="true"
app:behavior_overlapTop="10dp"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<!--<include layout="#layout/activity_chapters" />-->
<com.chalklit.widget.NonScrollListView
android:id="#+id/lv_modules_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white"
android:divider="#null"
android:scrollbars="none"></com.chalklit.widget.NonScrollListView>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
CollapsingToolbarActivity.java
private CollapsingToolbarLayout collapsingToolbarLayout = null;
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_collapsing_toolbar);
final Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
toolbar.inflateMenu(R.menu.menu_main);
setSupportActionBar(toolbar);
ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
collapsingToolbarLayout = (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
collapsingToolbarLayout.setTitle(" ");
collapsingToolbarLayout.setContentScrimColor(getResources().getColor(R.color.base_color_theme_new));
collapsingToolbarLayout.setStatusBarScrimColor(getResources().getColor(R.color.base_color_theme_new));
}

I have preperead two amaizing avatar collapsing demo samples with approach that doesn’t use a custom CoordinatorLayoutBehavior!
To view my samples native code: "Collapsing Avatar Toolbar Sample"
To read my "Animation Collapsing Toolbar Android" post on Medium.
demo 1 demo 2
Instead of use use a custom CoordinatorLayoutBehavior i use an OnOffsetChangedListener which comes from AppBarLayout.
private lateinit var appBarLayout: AppBarLayout
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_demo_1)
...
appBarLayout = findViewById(R.id.app_bar_layout)
/**/
appBarLayout.addOnOffsetChangedListener(
AppBarLayout.OnOffsetChangedListener { appBarLayout, i ->
...
/**/
updateViews(Math.abs(i / appBarLayout.totalScrollRange.toFloat()))
})
}
Demo 1
in updateViews method avatar changes the size and changes avatar’s X, Y position translation in first demo.
private fun updateViews(offset: Float) {
...
/* Collapse avatar img*/
ivUserAvatar.apply {
when {
offset > avatarAnimateStartPointY -> {
val avatarCollapseAnimateOffset = (offset - avatarAnimateStartPointY) * avatarCollapseAnimationChangeWeight
val avatarSize = EXPAND_AVATAR_SIZE - (EXPAND_AVATAR_SIZE - COLLAPSE_IMAGE_SIZE) * avatarCollapseAnimateOffset
this.layoutParams.also {
it.height = Math.round(avatarSize)
it.width = Math.round(avatarSize)
}
invisibleTextViewWorkAround.setTextSize(TypedValue.COMPLEX_UNIT_PX, offset)
this.translationX = ((appBarLayout.width - horizontalToolbarAvatarMargin - avatarSize) / 2) * avatarCollapseAnimateOffset
this.translationY = ((toolbar.height - verticalToolbarAvatarMargin - avatarSize ) / 2) * avatarCollapseAnimateOffset
}
else -> this.layoutParams.also {
if (it.height != EXPAND_AVATAR_SIZE.toInt()) {
it.height = EXPAND_AVATAR_SIZE.toInt()
it.width = EXPAND_AVATAR_SIZE.toInt()
this.layoutParams = it
}
translationX = 0f
}
}
}
}
to find avatarAnimateStartPointY and avatarCollapseAnimationChangeWeight (for convert general offset to avatar animate offset):
private var avatarAnimateStartPointY: Float = 0F
private var avatarCollapseAnimationChangeWeight: Float = 0F
private var isCalculated = false
private var verticalToolbarAvatarMargin =0F
...
if (isCalculated.not()) {
avatarAnimateStartPointY =
Math.abs((appBarLayout.height - (EXPAND_AVATAR_SIZE + horizontalToolbarAvatarMargin)) / appBarLayout.totalScrollRange)
avatarCollapseAnimationChangeWeight = 1 / (1 - avatarAnimateStartPointY)
verticalToolbarAvatarMargin = (toolbar.height - COLLAPSE_IMAGE_SIZE) * 2
isCalculated = true
}
Demo 2
avatar change his size and than animate move to right at one moment with top toolbar text became to show and moving to left.
You need to track states: TO_EXPANDED_STATE changing, TO_COLLAPSED_STATE changing, WAIT_FOR_SWITCH.
/*Collapsed/expended sizes for views*/
val result: Pair<Int, Int> = when {
percentOffset < ABROAD -> {
Pair(TO_EXPANDED_STATE, cashCollapseState?.second ?: WAIT_FOR_SWITCH)
}
else -> {
Pair(TO_COLLAPSED_STATE, cashCollapseState?.second ?: WAIT_FOR_SWITCH)
}
}
Create animation for avatar on state switch change:
result.apply {
var translationY = 0f
var headContainerHeight = 0f
val translationX: Float
var currentImageSize = 0
when {
cashCollapseState != null && cashCollapseState != this -> {
when (first) {
TO_EXPANDED_STATE -> {
translationY = toolbar.height.toFloat()
headContainerHeight = appBarLayout.totalScrollRange.toFloat()
currentImageSize = EXPAND_AVATAR_SIZE.toInt()
/**/
titleToolbarText.visibility = View.VISIBLE
titleToolbarTextSingle.visibility = View.INVISIBLE
background.setBackgroundColor(ContextCompat.getColor(this#Demo2Activity, R.color.color_transparent))
/**/
ivAvatar.translationX = 0f
}
TO_COLLAPSED_STATE -> {
background.setBackgroundColor(ContextCompat.getColor(this#Demo2Activity, R.color.colorPrimary))
currentImageSize = COLLAPSE_IMAGE_SIZE.toInt()
translationY = appBarLayout.totalScrollRange.toFloat() - (toolbar.height - COLLAPSE_IMAGE_SIZE) / 2
headContainerHeight = toolbar.height.toFloat()
translationX = appBarLayout.width / 2f - COLLAPSE_IMAGE_SIZE / 2 - margin * 2
/**/
ValueAnimator.ofFloat(ivAvatar.translationX, translationX).apply {
addUpdateListener {
if (cashCollapseState!!.first == TO_COLLAPSED_STATE) {
ivAvatar.translationX = it.animatedValue as Float
}
}
interpolator = AnticipateOvershootInterpolator()
startDelay = 69
duration = 350
start()
}
...
}
}
ivAvatar.apply {
layoutParams.height = currentImageSize
layoutParams.width = currentImageSize
}
collapsingAvatarContainer.apply {
layoutParams.height = headContainerHeight.toInt()
this.translationY = translationY
requestLayout()
}
/**/
cashCollapseState = Pair(first, SWITCHED)
}
To view my samples native code: "Collapsing Avatar Toolbar Sample"

Here's another approach that doesn't use a custom CoordinatorLayoutBehavior.
It uses an OnOffsetChangedListener which comes from AppBarLayout.
Here's a snippet:
class OnOffsetChangedListener implements AppBarLayout.OnOffsetChangedListener {
#Override
public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
final int scrollRange = appBarLayout.getTotalScrollRange();
float offsetFactor = (float) (-verticalOffset) / (float) scrollRange;
...
This shows you how to find the total scroll range and then find the ratio between the total scroll range and the current scroll position. This is what you need to figure out how to scale and position your toolbar views.
For a custom layout (like I did), you can override onAttachedToWindow and add the listener there:
// Add an OnOffsetChangedListener if possible
final ViewParent parent = getParent();
if (parent instanceof AppBarLayout) {
if (mOnOffsetChangedListener == null) {
mOnOffsetChangedListener = new OnOffsetChangedListener();
}
((AppBarLayout) parent).addOnOffsetChangedListener(mOnOffsetChangedListener);
}
I found this approach to be a little simpler than creating a custom behavior.
I created an example project on GitHub. The app looks like this:
You can see the whole project at https://github.com/klarson2/Collapsing-Image

you should add Line #33
<?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:fitsSystemWindows="true">
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/appbar_layout"
android:layout_width="match_parent"
android:layout_height="192dp"
android:fitsSystemWindows="true"
android:theme="#style/AppTheme">
<com.google.android.material.appbar.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
app:layout_scrollFlags="scroll|snap|exitUntilCollapsed"
app:title="Collapsing"
app:toolbarId="#+id/toolbar">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="centerCrop"
android:src="#drawable/nana"
app:layout_collapseMode="parallax" />
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_collapseMode="pin" />
</com.google.android.material.appbar.CollapsingToolbarLayout>
</com.google.android.material.appbar.AppBarLayout>
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp"
app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="#drawable/ax" />
</androidx.core.widget.NestedScrollView>
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/floating_action_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:baselineAlignBottom="false"
android:clickable="true"
android:src="#drawable/possetive"
app:fabSize="normal"
app:layout_anchor="#id/appbar_layout"
app:layout_anchorGravity="bottom|right"
app:rippleColor="#E4D6D6" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>

To achieve this, we must have to create custom behavior using CoordinatorLayout.Behavior
Take into account two core elements: child and dependency:
The child is the view that enhances behavior, dependency who will serve as a trigger to interact with the child element. In your requirement the child is the ImageView and the dependency is the Toolbar, in that way, if the Toolbar moves, the ImageView will move too.
Please check some below links for custome behaviour toolbar demos
http://www.devexchanges.info/2016/03/android-tip-custom-coordinatorlayout.html
https://medium.com/google-developers/intercepting-everything-with-coordinatorlayout-behaviors-8c6adc140c26#.tfsd7ftkl