Develop Reference

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);
}
});
}

Show/hide BottomNavigationView on scroll in CoordinatorLayout with AppBarLayout

I am trying to use both AppBarLayout and BottomNavigationLayout in a single CoordinatorLayout and I'm having difficulties hiding the BottomNavigationLayout as required by the material guideline.
I mean something 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"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="false">
<android.support.design.widget.AppBarLayout
android:id="#+id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_insetEdge="top"
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:popupTheme="#style/AppTheme.PopupOverlay"
app:layout_scrollFlags="scroll|enterAlways"/>
</android.support.design.widget.AppBarLayout>
<android.support.design.widget.BottomNavigationView
android:id="#+id/bottom_nav"
android:layout_width="match_parent"
android:layout_height="56dp"
android:layout_gravity="bottom"
app:menu="#menu/menu_bottom_navigation"/>
<FrameLayout
android:id="#+id/content_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>
As you can see, I also have a FrameLayout that's used to contain a fragment with the actual content. Currently there are no default/built-in behaviors for the BottomNavigationView - neither for the view itself, nor for its siblings. The existing appbar_scrolling_view_behavior handles the content view in coordination with the appbar but ignores other siblings.
I am looking for a solution to hide and show both the appbar and the bottom navigation view on scroll.

After a day or two of searching I settled with a custom Behavior attached to the BottomNavigationView. Its main idea is to detect when the BottomNavigationView's sibling is scrolled so that it can hide the BottomNavigationView. Something like this:
public class BottomNavigationBehavior extends CoordinatorLayout.Behavior<BottomNavigationView> {
public BottomNavigationBehavior() {
super();
}
public BottomNavigationBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean layoutDependsOn(CoordinatorLayout parent, BottomNavigationView child, View dependency) {
boolean dependsOn = dependency instanceof FrameLayout;
return dependsOn;
}
#Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, BottomNavigationView child, View directTargetChild, View target, int nestedScrollAxes) {
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL;
}
#Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, BottomNavigationView child, View target, int dx, int dy, int[] consumed) {
if(dy < 0) {
showBottomNavigationView(child);
}
else if(dy > 0) {
hideBottomNavigationView(child);
}
}
private void hideBottomNavigationView(BottomNavigationView view) {
view.animate().translationY(view.getHeight());
}
private void showBottomNavigationView(BottomNavigationView view) {
view.animate().translationY(0);
}
}
As you can see, I'm using simple ViewPropertyAnimator, obtained using the child views's animate method. This leads to a simple animation that doesn't really match the AppBarLayout's behavior but it's decent enough to look good and at the same time it's simple enough to implement.
I expect that at some point the Android team will add a default Behavior for the BottomNavigationView in the support library so I don't think it's reasonable to invest a lot more time to exactly duplicate the AppBarLayout's behavior.
edit (April 2018): see the comments section for a minor clarification about onStartNestedScroll and onNestedPreScroll and their new versions.

You can also use HideBottomViewOnScrollBehavior. This behavior works in basically the same way, but also handles cancelling any existing animations that are running which should be better for performance.

Android design Library AppBar scrolling behavior enterAlways

I am using the latest version of the design support library (23.1.1) and I am facing an issue when I use the CollapsingToolbarLayout with the enterAlways scroll flag. Basically, when you scroll back up, the view appears but if also leaves a empty white space at top.
Normal View:
After scrolling down and then back up (notice the whitespace below status bar):
MainActivity.java
public class MainActivity extends AppCompatActivity {
AppBarLayout appBar;
View expandedView;
Toolbar toolbar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
setTitle("");
initViews();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private void initViews() {
appBar = (AppBarLayout) findViewById(R.id.appBar);
appBar.addOnOffsetChangedListener(appBarOffsetChangedListener);
expandedView = findViewById(R.id.expandedView);
RecyclerView rv = (RecyclerView) findViewById(R.id.rv);
rv.setLayoutManager(new LinearLayoutManager(this));
rv.setAdapter(new DummyAdapter());
}
private AppBarLayout.OnOffsetChangedListener appBarOffsetChangedListener = new AppBarLayout.OnOffsetChangedListener() {
#Override
public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
int maxOffset = appBar.getTotalScrollRange();
verticalOffset = Math.abs(verticalOffset);
if(verticalOffset > maxOffset)
return;
float percentage = verticalOffset / (float) maxOffset;
if(expandedView!=null)
expandedView.setAlpha(1 - percentage);
}
};
}
activity_main.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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.media2359.fragmenttoolbarchange.MainActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/appBar"
android:layout_width="match_parent"
android:layout_height="180dp"
android:background="#color/colorPrimaryDark"
android:fitsSystemWindows="true">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsingToolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
app:layout_scrollFlags="scroll|exitUntilCollapsed|enterAlways">
<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.v7.widget.Toolbar>
<RelativeLayout
android:id="#+id/expandedView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:paddingLeft="#dimen/toolbar_text_margin_left"
android:paddingTop="#dimen/toolbar_text_margin_top"
tools:background="#color/colorPrimaryDark">
<TextView
android:id="#+id/tvName"
style="#style/TextAppearance.AppCompat.Headline"
android:layout_width="#dimen/toolbar_text_width"
android:layout_height="wrap_content"
android:text="Hello" />
<TextView
android:id="#+id/tvTime"
style="#style/TextAppearance.AppCompat.Body1"
android:layout_width="#dimen/toolbar_text_width"
android:layout_height="wrap_content"
android:layout_below="#id/tvName"
android:layout_marginTop="7dp"
android:text="04 Feb, Tuesday evening" />
</RelativeLayout>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/rv"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:listitem="#layout/item_dummy" />
</android.support.design.widget.CoordinatorLayout>
Using enterAlwaysCollapsed along with enterAlways avoids this issue but I want the full view to come back because in the actual app, the expanded section is way smaller.
Another thing that I have noticed is that, the height of the whitespace is equal to the height to the toolbar.
EDIT 1
I replaced exitUntilCollapsed with snap and then there wasn't any white space but then the toolbar doesn't pin and scrolls away
EDIT 2
Looks like this is an issue with the Design Library: CollapsingToolbarLayout enterAlways not supported
Temporary Workaround: Cheesesquare: enterAlways produces wrong layout

Perhaps that's because of:
enterAlways
Which the codepath/android_guides says:
enterAlways: The view will become visible when scrolling up. This flag
is useful in cases when scrolling from the bottom of a list and
wanting to expose the Toolbar as soon as scrolling up takes place.
Maybe you wanna try this: (standard way)
app:layout_scrollFlags="scroll|exitUntilCollapsed"
Honestly, I didn't see somebody is using enterAlways in CollapsingToolbarLayout in my whole development life.Especially, with those two flags:
app:layout_scrollFlags="scroll|exitUntilCollapsed|enterAlways"
Otherwise, It could be a bug and needs the Google's staffs to answer about it.

How to make the Toolbar snap into view or out of view when using Google Design Library?

I am trying to achieve an effect like WhatsApp has, where the Toolbar (when scrolled) will clip into view magnetlike, or out of view magnetlike.
What I have im my MainActivity XML:
DrawerLayout - Base Layout
CoordinatorLayout - Layout for the Appbar and Toolbar and Tabs
AppBarLayout - For holding Toolbar and Tabs
Toolbar - has THIS flag: app:layout_scrollFlags="scroll|enterAlways"
SlidingTabLayout - Displays tabs
ViewPager - For tabs
RecyclerView - For coordinatorlayout
Now dont get me wrong, it works, when I scroll down the toolbar gets pushed out of view but say I stop scrolling halfway, then the toolbar just sits there half hidden out of view and the other half in view..
How can I approach solving this problem, as I want it to either snap out of view or into view.

This feature has been added in 23.1.0 version of android support library.
From release notes:
Added edge snapping support to the AppBarLayout class by adding the
SCROLL_FLAG_SNAP constant. When scrolling ends, if the view is only
partially visible, the view is snapped and scrolled to its closest
edge.
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
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="wrap_content"
app:layout_scrollFlags="scroll|enterAlways|snap" />
-----
-----
For more info: http://android-developers.blogspot.in/2015/10/android-support-library-231.html

EDIT: as of support 23.1.0 this is no longer needed. See this answer instead.
One possible way to solve this is customizing the Behavior set to your AppBarLayout.
<android.support.design.widget.AppBarLayout
app:layout_behavior="com.myapp.AppBarLayoutSnapBehavior"
android:layout_width="match_parent"
android:layout_height="wrap_content">
...
Your AppBarLayoutSnapBehavior would change the default behavior of AppBarLayout.Behavior, by adding the snap logic when the scroll stops.
Hopefully, the code below is self explanatory.
package com.myapp;
public class AppBarLayoutSnapBehavior extends AppBarLayout.Behavior {
private ValueAnimator mAnimator;
private boolean mNestedScrollStarted = false;
public AppBarLayoutSnapBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child,
View directTargetChild, View target, int nestedScrollAxes) {
mNestedScrollStarted = super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
if (mNestedScrollStarted && mAnimator != null) {
mAnimator.cancel();
}
return mNestedScrollStarted;
}
#Override
public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target) {
super.onStopNestedScroll(coordinatorLayout, child, target);
if (!mNestedScrollStarted) {
return;
}
mNestedScrollStarted = false;
int scrollRange = child.getTotalScrollRange();
int topOffset = getTopAndBottomOffset();
if (topOffset <= -scrollRange || topOffset >= 0) {
// Already fully visible or fully invisible
return;
}
if (topOffset < -(scrollRange / 2f)) {
// Snap up (to fully invisible)
animateOffsetTo(-scrollRange);
} else {
// Snap down (to fully visible)
animateOffsetTo(0);
}
}
private void animateOffsetTo(int offset) {
if (mAnimator == null) {
mAnimator = new ValueAnimator();
mAnimator.setInterpolator(new DecelerateInterpolator());
mAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
setTopAndBottomOffset((int) animation.getAnimatedValue());
}
});
} else {
mAnimator.cancel();
}
mAnimator.setIntValues(getTopAndBottomOffset(), offset);
mAnimator.start();
}
}
The only thing is, the scroll view (in my case a RecyclerView) snaps along with the Toolbar. I actually like it this way, but I'm not sure that's what you want.

I just hided action bar layout in main activity and set span for CollapsingToolbarLayout.
it works for me.
in main activity
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().hide();
CollapsingToolbarLayout collapsingToolbar =
(CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
collapsingToolbar.setTitle("Name");
loadBackdrop();
and layout_activity_main
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="#dimen/detail_backdrop_height"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
android:fitsSystemWindows="true">
<android.support.design.widget.CollapsingToolbarLayout
android:id="#+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_scrollFlags="scroll|snap"
android:fitsSystemWindows="true"
app:contentScrim="?attr/colorPrimary"
app:expandedTitleMarginStart="48dp"
app:expandedTitleMarginEnd="64dp">
<ImageView
android:id="#+id/backdrop"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="centerCrop"
android:fitsSystemWindows="true"
app:layout_collapseMode="parallax" />
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:layout_collapseMode="pin" />
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>

Show view when toolbar collapses

I have an activity with a CoordinatorLayout, AppBarLayout, CollapsingToolbarLayout and Toolbar. So, basically, a view that collapses when scrolling a RecyclerView.
What I need to do is to show a custom view when the view of the expanded layout is hidden due to collapsing.
This is my layout:
<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:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="192dp"
android:fitsSystemWindows="true"
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="#2196F3"
app:expandedTitleMarginBottom="32dp"
app:expandedTitleMarginEnd="64dp"
app:expandedTitleMarginStart="48dp"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<include
android:id="#+id/header"
layout="#layout/header_big_first_screen"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:scaleType="centerCrop"
app:layout_collapseMode="parallax"/>
<android.support.v7.widget.CollapsingToolbarLayout
android:id="#+id/anim_toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:layout_collapseMode="pin"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Hello!"/>
</android.support.v7.widget.CollapsingToolbarLayout>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/categories_recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>
In the end, when the toolbar is expanded the view loaded with the element is shown. When it is collapsed it doesn't . When it disappears the TextView inside Toolbarshould be shown. Currently it shows all the time.
I've been looking in the events of CollapsingToolbarLayout to add a listener when it changes size so I can check if that is smaller than a value and show that view.
This can be kind of tricky to explain but I believe I made myself clear. I've been googling around and cannot find anyone trying to do the same.

Taking a look at the CollapsingToolbarLayout source, the content scrim animations are triggered via an OnOffsetChangedListener on the AppBarLayout. So you could add another one to trigger alpha animations on your text view:
mListener = new AppBarLayout.OnOffsetChangedListener() {
#Override
public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
if(collapsingToolbar.getHeight() + verticalOffset < 2 * ViewCompat.getMinimumHeight(collapsingToolbar)) {
hello.animate().alpha(1).setDuration(600);
} else {
hello.animate().alpha(0).setDuration(600);
}
}
};
appBar.addOnOffsetChangedListener(mListener);

Instead of trying to replicate when the scrim is supposed to show (collapsed) or not (expanded), a better way is to override the setScrimsShown method, which is called every time inside the CollapsingToolbarLayout's onOffsetChanged, and add a listener to it like this:
public class CollapsingToolbarLayoutWithScrimListener extends CollapsingToolbarLayout {
public CollapsingToolbarLayoutWithScrimListener(Context context) {
super(context);
}
public CollapsingToolbarLayoutWithScrimListener(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CollapsingToolbarLayoutWithScrimListener(Context context, AttributeSet attrs, int defStyleAttr) {
super(context,attrs,defStyleAttr);
}
private ScrimListener scrimListener = null;
#Override
public void setScrimsShown(boolean shown, boolean animate) {
super.setScrimsShown(shown, animate);
if (scrimListener != null)
scrimListener.onScrimShown(shown);
}
public void setScrimListener(ScrimListener listener) {
scrimListener = listener;
}
public interface ScrimListener {
void onScrimShown(boolean shown);
}
}