Develop Reference

BottomNavigationView is not responding to scroll events inside Coordinator Layout

I have an activity in which there is a ViewPager and the BottomNavigationView at the bottom of the page. The ViewPager consists of few fragments in it.
Below is the layout for the activity
<LinearLayout 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">
<include layout="#layout/toolbar_with_tab_strip_layout" />
<android.support.design.widget.CoordinatorLayout
android:id="#+id/coordinatorlayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.tf.eros.faythTv.widgets.NonScrollingViewPager
android:id="#+id/home_viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/bottom_navigation_home"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="#color/white"
app:elevation="16dp"
app:itemIconTint="#drawable/home_bottombar_icon_color_selector"
app:itemTextColor="#drawable/home_bottombar_icon_color_selector"
app:menu="#menu/bottom_navigation_main" />
</android.support.design.widget.CoordinatorLayout>
</LinearLayout>
And I have also added a BottomNavigationViewBehavior class that will be handling the hiding/unhiding of the BottomNavigationView on scrolling of the fragments in the viewpager
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(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) {
slideDown(child);
} else if (dy < 0) {
slideUp(child);
}
}
#Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, BottomNavigationView child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
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);
}
}
In the Activity I have added these two lines in the onCreate Method
CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) bottomNavigationView.getLayoutParams();
layoutParams.setBehavior(new BottomNavigationViewBehavior());
The aim is to hide the BottomNavigationView when the page is scrolled down(dy > 0) and make it visible when it is scrolled up (dy < 0).
Now the issue with the code is the hiding and unhiding of the BottomNavigationView is not spontaneous with the scrolling. Sometimes it doesn't hide at all while scrolling.

onNestedScroll called only once

I have a class
public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
super();
}
public ScrollAwareFABBehavior() {
super();
}
#Override
public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,final View directTargetChild, final View target, final int nestedScrollAxes) {
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL;
}
#Override
public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,final View target, final int dxConsumed, final int dyConsumed,final int dxUnconsumed, final int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
child.hide();
} else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
child.show();
}
}
}
the problem is that onNestedScroll is called only once when I scroll up a recyclerview, so the fab is hiding and never shows again. Here is layout I am using
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.widget.SwipeRefreshLayout
android:id="#+id/refresh_layout"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="#+id/list"
app:layoutManager="#string/vertical_linear_layout_manager"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</android.support.v4.widget.SwipeRefreshLayout>
<android.support.design.widget.FloatingActionButton
android:id="#+id/add"
android:layout_width="wrap_content"
app:layout_behavior="mypackagename.util.ScrollAwareFABBehavior"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
app:useCompatPadding="true"
android:layout_margin="16sp"
android:src="#drawable/ic_add"/>
</android.support.design.widget.CoordinatorLayout>
My support libraries version is 25.1.0

I solved the problem changing the visibility from GONE to INVISIBLE with the following code.
#Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child,
View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed,
dyUnconsumed);
if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
child.hide(new FloatingActionButton.OnVisibilityChangedListener() {
#Override
public void onShown(FloatingActionButton fab) {
super.onShown(fab);
}
#Override
public void onHidden(FloatingActionButton fab) {
super.onHidden(fab);
fab.setVisibility(View.INVISIBLE);
}
});
} else if (dyConsumed <= 0 && child.getVisibility() != View.VISIBLE) {
child.show();
}
}

I have just answered
to absolutely the same problem in another post, check it.
Speaking shortly, use the following:
compile 'com.android.support:design:25.0.1'

#Override
public void onNestedScroll(#NonNull CoordinatorLayout coordinatorLayout, #NonNull FloatingActionButton child, #NonNull View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, type);
if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
child.hide(new FloatingActionButton.OnVisibilityChangedListener() {
#Override
public void onHidden(FloatingActionButton fab) {
super.onHidden(fab);
fab.setVisibility(View.INVISIBLE);
}
});
} else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
child.show();
}
}

Do not set the visibility of FAB to GONE in child.hide() - use INVISIBLE instead. From 25.1.0, the scroll events are not passed on to views whose visibility is GONE

For me i replace child.hide() with ((View)child).setVisibility(View.INVISIBLE).

Scroll aware FAB hides, but then does not reappear

I have made an Android app with a recyclerview and a floating action button. When scrolling down, the button should hide, when scrolling up it should show again. I have used this tutorial to implement the behavior.
The result is, that the FAB hides when I scroll down, but when scrolling up it does not reappear again :( The class ScrollAwareFABBehavior is identical from the tutorial. But I'm using nested layouts.
Here is my layout (the recyclerview is in a LinearLayout in content_main):
<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="org.myorganisation.mypackage.someActivity">
<include layout="#layout/toolbar" />
<include layout="#layout/content_main" />
<android.support.design.widget.FloatingActionButton
android:id="#+id/add_fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="#dimen/fab_margin"
android:src="#drawable/plus"
app:layout_behavior="org.myorganisation.mypackage.someActivity.helpers.ScrollAwareFABBehavior" />
<LinearLayout
android:id="#+id/insert_alert"
android:layout_width="wrap_content"
android:layout_height="50sp"
android:layout_margin="#dimen/fab_margin"
android:gravity="center_vertical"
android:orientation="horizontal"
android:paddingEnd="70sp"
android:visibility="gone"
app:layout_anchor="#id/add_fab"
app:layout_anchorGravity="bottom|left">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:text="#string/initial_alert"
android:textColor="#color/colorPrimaryDark"
android:textStyle="bold|italic" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_keyboard_arrow_right_black_24sp"
android:tint="#color/colorPrimary" />
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>

As of version 25.1.0 of the Support Library, hidden views no longer scroll events as per this bug.
As mentioned in comment #5:
This is working as intended, your dependency chain is the wrong way. Your RecyclerView (Behavior) should be triggering the FAB visibility change.

As for support library version 25.1.0, the solution is here.

Here is simple solution:
The concept behind this is very simple, you just need to detect when user scrolls down and up the RecyclerView. In Android there are some built in methods that can help us detect when user is scrolling either side in Recyclerview. See the code below, since it will show the full concept:
RecyclerView rv = (RecyclerView)findViewById(R.id.rv);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
rv.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy < 0) {
fab.show();
} else if (dy > 0) {
fab.hide();
}
}
});

I solved this problem by replacing
.setVisibility(View.VISIBLE) with .show(true) and
.setVisibility(View.GONE) with .hide(true):
And here is my class for the Behaviour, that works with 25.1.0: and Clans FloatingActionButton
public class ScrollAwareFABBehavior extends CoordinatorLayout.Behavior<FloatingActionButton> {
private static boolean mIsAnimatingOut = false;
private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
super();
}
#Override
public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton fabButton, View dependency) {
return dependency instanceof Snackbar.SnackbarLayout;
}
#Override
public boolean onDependentViewChanged(CoordinatorLayout parent, FloatingActionButton fabButton, View dependency) {
float translationY = Math.min(0, dependency.getTranslationY() - dependency.getHeight());
fabButton.setTranslationY(translationY);
return true;
}
#Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout,
FloatingActionButton fabButton, View directTargetChild, View target, int nestedScrollAxes) {
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL ||
super.onStartNestedScroll(coordinatorLayout, fabButton, directTargetChild, target,
nestedScrollAxes);
}
#Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton fabButton,
View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, fabButton, target, dxConsumed, dyConsumed, dxUnconsumed,
dyUnconsumed);
if (fabButton.isEnabled()) {
if (dyConsumed > 0 && !mIsAnimatingOut && fabButton.isShown()) {
animateOut(fabButton);
} else if ((dyConsumed < 0 || dyUnconsumed < 0) && fabButton.isHidden()) {
animateIn(fabButton);
}
}
}
public static void animateOut(final FloatingActionButton fabButton) {
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(fabButton).translationY(168F).alpha(0.0F).setInterpolator(INTERPOLATOR).withLayer()
.setListener(new ViewPropertyAnimatorListener() {
public void onAnimationStart(View view) {
mIsAnimatingOut = true;
}
public void onAnimationCancel(View view) {
mIsAnimatingOut = false;
}
public void onAnimationEnd(View view) {
mIsAnimatingOut = false;
fabButton.hide(true);
}
}).start();
} else {
Animation anim = AnimationUtils.loadAnimation(fabButton.getContext(), android.R.anim.fade_in);
anim.setInterpolator(INTERPOLATOR);
anim.setDuration(200L);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {
mIsAnimatingOut = true;
}
public void onAnimationEnd(Animation animation) {
mIsAnimatingOut = false;
fabButton.hide(true);
}
#Override
public void onAnimationRepeat(final Animation animation) {
}
});
fabButton.startAnimation(anim);
}
}
public static void animateIn(FloatingActionButton fabButton) {
fabButton.show(true);
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(fabButton).translationY(0).scaleX(1.0F).scaleY(1.0F).alpha(1.0F)
.setInterpolator(INTERPOLATOR).withLayer().setListener(null)
.start();
} else {
Animation anim = AnimationUtils.loadAnimation(fabButton.getContext(), android.R.anim.fade_out);
anim.setDuration(200L);
anim.setInterpolator(INTERPOLATOR);
fabButton.startAnimation(anim);
}
}
}

Android -FAB Behaviour with half list

I have the FAB working when recyclerview has enough items to scroll, but i need to handle the case when recyclerview does not scroll (the total of items do not cover the screen).
At the moment this is how I handle the scroll:
public class FABBehavior extends FloatingActionButton.Behavior {
public FABBehavior() {
super();
}
public FABBehavior(final Context context, final AttributeSet attrs) {
super(context, attrs);
}
#Override
public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child, final View target, final int dxConsumed, final int dyConsumed, final int dxUnconsumed, final int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
if (dyConsumed > 0) {
CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) child.getLayoutParams();
int fab_bottomMargin = layoutParams.bottomMargin;
child.animate().translationY(child.getHeight() + fab_bottomMargin).setInterpolator(new LinearInterpolator()).start();
} else if (dyConsumed < 0) {
child.animate().translationY(0).setInterpolator(new LinearInterpolator()).start();
}
}
#Override
public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child, final View directTargetChild, final View target, final int nestedScrollAxes) {
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL;
}
}
How to handle when recyclerview has few items?

You have to handle another case independently from CoordinatorLayout.
override a function layoutDependsOn:
#Override
public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
return super.layoutDependsOn(parent, child, dependency) || dependency instanceof RecyclerView;
}
onNestedScroll should also handle another case:
if (target instanceof RecyclerView) {
handleRecyclerViewScrolling(target, child);
return;
}
handleRecyclerViewScrolling should look like:
private void handleRecyclerViewScrolling(View target, FloatingActionButton child) {
if (scrollListener != null) {
return;
}
RecyclerView recyclerView = (RecyclerView) target;
scrollListener = new RecyclerViewScrollListener(child);
recyclerView.addOnScrollListener(scrollListener);
}
scrollListener should be a field in your FABBehavior class. Also declare inner class inside FABBehavior:
private class RecyclerViewScrollListener extends RecyclerView.OnScrollListener {
FloatingActionButton mChild;
public RecyclerViewScrollListener(FloatingActionButton child) {
this.mChild = child;
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
mChild.show();
} else {
mChild.hide();
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (!recyclerView.canScrollVertically(Integer.MAX_VALUE)) {
mChild.show();
}
}
}
RecyclerViewScrollListener hides FAB, when it is scrolling and shows it when it is in idle state.

How to animate both top and bottom Toolbars(or any other view) enter/exit screen on scroll in CoordinatorLayout?

My activity contains 2 AppBarLayouts in a CoordinatorLayout, one on the top of screen, and the other bottom. I want to make both of the 2 AppBarLayouts hide on scroll of a RecyclerView.
When there is only the top one, it's easy to make it hide on scroll by adding app:layout_scrollFlags="scroll|enterAlways" to the Toolbar, and app:layout_behavior="#string/appbar_scrolling_view_behavior" to the container of RecyclerView.
When there is only the bottom AppBarLayout which hide on scroll, it was realized by making a custom behavior BottomAppBarLayoutBehavior extends AppBarLayout.Behavior.
However, when both of them are made hide on scroll, they succeed to hide but the RecyclerView shakes on scroll. And the area of top Toolbar leaves empty white space after hiding.
Below is the xml:
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/topToolbar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|enterAlways" />
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:layout_width="fill_parent"
android:orientation="vertical"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:id="#+id/RecyclerViewContainer"
android:layout_height="fill_parent"/>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_gravity="bottom"
app:layout_behavior="myPackage.BottomAppBarLayoutBehavior">
<LinearLayout
android:layout_width="match_parent"
android:orientation="horizontal"
android:layout_height="match_parent">
<!-- some Views -->
</LinearLayout>
</android.support.design.widget.AppBarLayout>
</android.support.design.widget.CoordinatorLayout>
Below is the code of BottomAppBarLayoutBehavior:
public class BottomAppBarLayoutBehavior extends AppBarLayout.Behavior {
private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
private boolean mIsAnimatingOut = false;
public BottomAppBarLayoutBehavior(Context context, AttributeSet attrs) {
super();
}
#Override
public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final AppBarLayout child,
final View directTargetChild, final View target, final int nestedScrollAxes) {
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL
|| super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
}
#Override
public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final AppBarLayout child,
final View target, final int dxConsumed, final int dyConsumed,
final int dxUnconsumed, final int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
if (dyConsumed > 0 && !this.mIsAnimatingOut && child.getVisibility() == View.VISIBLE) {
animateOut(child);
} else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
animateIn(child);
}
}
private void animateOut(final AppBarLayout appBarLayout) {
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(appBarLayout).translationY(168F).alpha(0.0F).setInterpolator(INTERPOLATOR).withLayer()
.setListener(new ViewPropertyAnimatorListener() {
public void onAnimationStart(View view) {
BottomAppBarLayoutBehavior.this.mIsAnimatingOut = true;
}
public void onAnimationCancel(View view) {
BottomAppBarLayoutBehavior.this.mIsAnimatingOut = false;
}
public void onAnimationEnd(View view) {
BottomAppBarLayoutBehavior.this.mIsAnimatingOut = false;
view.setVisibility(View.GONE);
}
}).start();
} else {
Animation anim = AnimationUtils.loadAnimation(appBarLayout.getContext(), R.anim.fab_out);
anim.setInterpolator(INTERPOLATOR);
anim.setDuration(200L);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {
BottomAppBarLayoutBehavior.this.mIsAnimatingOut = true;
}
public void onAnimationEnd(Animation animation) {
BottomAppBarLayoutBehavior.this.mIsAnimatingOut = false;
appBarLayout.setVisibility(View.GONE);
}
#Override
public void onAnimationRepeat(final Animation animation) {
}
});
appBarLayout.startAnimation(anim);
}
}
private void animateIn(AppBarLayout appBarLayout) {
appBarLayout.setVisibility(View.VISIBLE);
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(appBarLayout).scaleX(1.0F).scaleY(1.0F).alpha(1.0F)
.setInterpolator(INTERPOLATOR).withLayer().setListener(null)
.start();
} else {
Animation anim = AnimationUtils.loadAnimation(appBarLayout.getContext(), R.anim.fab_in);
anim.setDuration(200L);
anim.setInterpolator(INTERPOLATOR);
appBarLayout.startAnimation(anim);
}
}
}

I have found the solution by myself. The AppBarLayout wrapper for the bottom LinearLayout is redundant. Remove the AppBarLayout wrapper and make the Behavior class extends CoordinatorLayout.Behavior<LinearLayout>. Finally add the behavior to LinearLayout, then the top Toolbar and bottom LinearLayout enter and exit screen on scroll correctly.
The correct activity xml:
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/top_toolbar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
app:layout_scrollFlags="scroll|enterAlways" />
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:layout_width="fill_parent"
android:orientation="vertical"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:id="#+id/recycler_view_container"
android:layout_height="fill_parent"/>
<LinearLayout
android:id="#+id/bottom_bar"
android:layout_width="match_parent"
android:orientation="horizontal"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:layout_behavior="*THE_FULL_PACKAGE_NAME*.LinearLayoutBehavior ">
<!-- child views -->
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
The correct Behavior class:
public class LinearLayoutBehavior extends CoordinatorLayout.Behavior<LinearLayout> {
private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
private boolean mIsAnimatingOut = false;
public LinearLayoutBehavior(Context context, AttributeSet attrs) {
super();
}
#Override
public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final LinearLayout child,
final View directTargetChild, final View target, final int nestedScrollAxes) {
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL
|| super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
}
#Override
public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final LinearLayout child,
final View target, final int dxConsumed, final int dyConsumed,
final int dxUnconsumed, final int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
if (dyConsumed > 0 && !this.mIsAnimatingOut && child.getVisibility() == View.VISIBLE) {
// User scrolled down and the FAB is currently visible -> hide the FAB
animateOut(child);
} else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
// User scrolled up and the FAB is currently not visible -> show the FAB
animateIn(child);
}
}
private void animateOut(final LinearLayout linearLayout) {
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(linearLayout).translationY(168F).alpha(0.0F).setInterpolator(INTERPOLATOR).withLayer()
.setListener(new ViewPropertyAnimatorListener() {
public void onAnimationStart(View view) {
LinearLayoutBehavior.this.mIsAnimatingOut = true;
}
public void onAnimationCancel(View view) {
LinearLayoutBehavior.this.mIsAnimatingOut = false;
}
public void onAnimationEnd(View view) {
LinearLayoutBehavior.this.mIsAnimatingOut = false;
view.setVisibility(View.GONE);
}
}).start();
} else {
Animation anim = AnimationUtils.loadAnimation(linearLayout.getContext(), R.anim.fab_out);
anim.setInterpolator(INTERPOLATOR);
anim.setDuration(200L);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {
LinearLayoutBehavior.this.mIsAnimatingOut = true;
}
public void onAnimationEnd(Animation animation) {
LinearLayoutBehavior.this.mIsAnimatingOut = false;
linearLayout.setVisibility(View.GONE);
}
#Override
public void onAnimationRepeat(final Animation animation) {
}
});
linearLayout.startAnimation(anim);
}
}
private void animateIn(LinearLayout linearLayout) {
linearLayout.setVisibility(View.VISIBLE);
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(linearLayout).translationY(0).scaleX(1.0F).scaleY(1.0F).alpha(1.0F)
.setInterpolator(INTERPOLATOR).withLayer().setListener(null)
.start();
} else {
Animation anim = AnimationUtils.loadAnimation(linearLayout.getContext(), R.anim.fab_in);
anim.setDuration(200L);
anim.setInterpolator(INTERPOLATOR);
linearLayout.startAnimation(anim);
}
}
}