Develop Reference

HideBottomViewOnScrollBehavior not working on recyclerview item expand/collapse

I am trying to hide text view on scroll down and show on scroll up it's working fine if I have an item like 10 or 15 but it's not working the same if I have less item
in recyclerview, I have expanded/collapse functionality so it's not the same sometimes
textview not hiding/visible some times I don't understand I added this line to my view which I want to hide/show on scroll
app:layout_behavior="com.google.android.material.behavior.HideBottomViewOnScrollBehavior"
XML
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:id="#+id/lnMain"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#mipmap/bg"
tools:context=".tab.history.view.HistoryFragment">
<com.google.android.material.appbar.AppBarLayout
android:id="#+id/mAppBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:elevation="0dp">
<RelativeLayout
android:id="#+id/lnActionBar"
android:layout_width="match_parent"
android:layout_height="?android:attr/actionBarSize"
android:background="#color/colorPrimary">
<TextView
android:id="#+id/tvtitle"
style="#style/fontMedium"
android:layout_width="wrap_content"
android:layout_height="?android:attr/actionBarSize"
android:layout_centerHorizontal="true"
android:gravity="center_vertical"
android:text="#string/beacon"
android:textColor="#color/white"
android:textSize="#dimen/header_font_size" />
</RelativeLayout>
</com.google.android.material.appbar.AppBarLayout>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rvBeacon"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:overScrollMode="never"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:paddingBottom="#dimen/_40sdp"
android:scrollbars="none"
android:visibility="visible"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
tools:itemCount="10"
tools:listitem="#layout/raw_beacon" />
<TextView
android:id="#+id/btnBack"
style="#style/fontBold"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="#dimen/_10sdp"
android:layout_marginBottom="#dimen/_20sdp"
android:background="#drawable/background_button_yellow_20dp"
android:contentDescription="#string/back_button"
android:drawableStart="#drawable/ic_back"
android:layout_gravity="bottom|center_horizontal"
android:drawablePadding="#dimen/_5sdp"
android:gravity="center"
android:padding="#dimen/_10sdp"
android:text="#string/back_to_search"
android:textColor="#color/white"
android:textSize="#dimen/button_font_size"
android:visibility="#{!isScanning ? View.VISIBLE: View.GONE}"
app:layout_behavior="com.google.android.material.behavior.HideBottomViewOnScrollBehavior" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
this is what I did so far but it's not working every time
Note:- Please not I have a recyclerview item which expands onclick so scroll and textview must behave according to that
Any help would be highly appriciated

i don't know why HideBottomViewOnScrollBehavior is not working for you
app:layout_behavior="com.google.android.material.behavior.HideBottomViewOnScrollBehavior"
may be it's beacause you have a expand/collapse functionality since you have only recyclerview only in screen so you can also perform this task by adding Custom ScrollListener
MyRecyclerScroll class
public abstract class MyRecyclerScroll extends RecyclerView.OnScrollListener {
private static final float HIDE_THRESHOLD = 100;
private static final float SHOW_THRESHOLD = 50;
int scrollDist = 0;
private boolean isVisible = true;
// We dont use this method because its action is called per pixel value change
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
// Check scrolled distance against the minimum
if (isVisible && scrollDist > HIDE_THRESHOLD) {
// Hide fab & reset scrollDist
hide();
scrollDist = 0;
isVisible = false;
}
// -MINIMUM because scrolling up gives - dy values
else if (!isVisible && scrollDist < -SHOW_THRESHOLD) {
// Show fab & reset scrollDist
show();
scrollDist = 0;
isVisible = true;
}
// Whether we scroll up or down, calculate scroll distance
if ((isVisible && dy > 0) || (!isVisible && dy < 0)) {
scrollDist += dy;
}
}
public abstract void show();
public abstract void hide();
}
Activity/Fragment
binding.rvBeacon.addOnScrollListener(object : MyRecyclerScroll() {
override fun show() {
binding.btnBack.animate().translationY(0f).setInterpolator(DecelerateInterpolator(2f)).start()
}
override fun hide() {
binding.btnBack.animate().translationY(binding.btnBack.getHeight() + 60f)
.setInterpolator(AccelerateInterpolator(2f)).start()
}
})
you can change animation, delay and margin according to your requirement
for more detail refer to this blog
Note: it will not work if your recyclerview inside scrollview

how about make custom behavior?
for example.
public class QuickReturnFooterBehavior extends CoordinatorLayout.Behavior<View> {
private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
private static final long ANIMATION_DURATION = 200;
private int dyDirectionSum;
private boolean isShowing;
private boolean isHiding;
private boolean isNeedOption = true;
public boolean isNeedOption() {
return isNeedOption;
}
public void setNeedOption(boolean needOption) {
isNeedOption = needOption;
}
public QuickReturnFooterBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean onStartNestedScroll(#NonNull CoordinatorLayout coordinatorLayout, #NonNull View child, #NonNull View directTargetChild, #NonNull View target, int axes, int type) {
return axes == ViewCompat.SCROLL_AXIS_VERTICAL;
}
#Override
public void onNestedPreScroll(#NonNull CoordinatorLayout coordinatorLayout, #NonNull View child, #NonNull View target, int dx, int dy, #NonNull int[] consumed, int type) {
// scroll chhange up and down
if (isNeedOption) {
showView(child);
} else {
if (dy > 0 && dyDirectionSum < 0
|| dy < 0 && dyDirectionSum > 0) {
child.animate().cancel();
dyDirectionSum = 0;
}
dyDirectionSum += dy;
if (dyDirectionSum > child.getHeight()) {
hideView(child);
} else if (dyDirectionSum < -child.getHeight()) {
showView(child);
}
}
}
private void hideView(final View view) {
if (isHiding || view.getVisibility() != View.VISIBLE) {
return;
}
ViewPropertyAnimator animator = view.animate()
.translationY(view.getHeight())
.setInterpolator(INTERPOLATOR)
.setDuration(ANIMATION_DURATION);
animator.setListener(new Animator.AnimatorListener() {
#Override
public void onAnimationStart(Animator animator) {
isHiding = true;
}
#Override
public void onAnimationEnd(Animator animator) {
isHiding = false;
view.setVisibility(View.INVISIBLE);
}
#Override
public void onAnimationCancel(Animator animator) {
// show when cancle
isHiding = false;
showView(view);
}
#Override
public void onAnimationRepeat(Animator animator) {
// no-op
}
});
animator.start();
}
private void showView(final View view) {
if (isShowing || view.getVisibility() == View.VISIBLE) {
return;
}
ViewPropertyAnimator animator = view.animate()
.translationY(0)
.setInterpolator(INTERPOLATOR)
.setDuration(ANIMATION_DURATION);
animator.setListener(new Animator.AnimatorListener() {
#Override
public void onAnimationStart(Animator animator) {
isShowing = true;
view.setVisibility(View.VISIBLE);
}
#Override
public void onAnimationEnd(Animator animator) {
isShowing = false;
}
#Override
public void onAnimationCancel(Animator animator) {
// show when cancle
isShowing = false;
hideView(view);
}
#Override
public void onAnimationRepeat(Animator animator) {
// no-op
}
});
animator.start();
}
}
UPDATE : for check can scroll in behavior
child.canScrollVertically(1) // "Top of list"
child.canScrollVertically(-1) // "End of list"
**UPDATE : add setter and getter **
private boolean isNeedOption = true;

Hide/Show many views onScroll RecyclerView

I have layout like that:
I would like to implement that functionality: When user ScrollDown RecyclerView two things which he see are Toolbar and FilterPanel. The title and image is hidden, when he scroll up till to the beggining of the recyclerview the title and image appear.
There is my HiddingScrollListener:
public abstract class HidingScrollListener extends RecyclerView.OnScrollListener {
private static final float HIDE_THRESHOLD = 10;
private int scrolledDistance = 0;
private boolean controlsVisible = true;
public HidingScrollListener() {
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (scrolledDistance > HIDE_THRESHOLD && controlsVisible) {
onHide();
controlsVisible = false;
scrolledDistance = 0;
} else if (scrolledDistance < -HIDE_THRESHOLD && controlsVisible) {
onShow();
controlsVisible = true;
scrolledDistance = 0;
}
if((controlsVisible && dy>0) || (!controlsVisible && dy<0)) {
scrolledDistance += dy;
}
}
public abstract void onShow();
public abstract void onHide();
}
And my implementation of this listener in activity:
mRecyclerView.addOnScrollListener(new HidingScrollListener() {
#Override
public void onShow() {
}
#Override
public void onHide() {
mTitle.setVisibility(View.GONE);
mImageView.setVisibility(View.GONE);
}
});
I don't know how to catch when RecyclerView is in the beggining and how to show title and image in this case. And I have a problem: How to pin FilterPanel under the Toolbar when I scroll down?
Anyway, thank you!

You should use the CoordinatorLayout from the android design support library.
This layout coordinates between it's children events, most commonly scroll events. Here is a tutorial: https://guides.codepath.com/android/Handling-Scrolls-with-CoordinatorLayout

Expand appbarlayout when recyclerview is scrolled/fling to top

I implemented a collapsingtoolbar layout with a recyclerview as shown in the sample code attached. My issue is that, when I fling the list downward, it does not go all the way to the top.
What happens is that, the scrolling stops right at the point where the AppBarLayout is supposed to end.
The effect that I want is upon flinging the list downward, the list will go all the way to the top AND reveal/expand the AppBarLayout
My minSdk is 14. Any help or suggestion is greatly appreciated.
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.AppBarLayout>
<android.support.design.widget.CollapsingToolbarLayout
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<LinearLayout
app:layout_collapseMode="parallax">
//some elements
</LinearLayout>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
app:layout_behavior="#string/appbar_scrolling_view_behavior"/> //value android.support.design.widget.AppBarLayout$ScrollingViewBehavior
<android.support.v7.widget.Toolbar
app:popupTheme="#style/AppTheme.PopupOverlay"
app:layout_collapseMode="parallax" />

I had similar problem and I used a simple trick to expand AppBarLayout when RecyclerView fling to top (you need to have support library >= 23.x.x)
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
int firstVisiblePosition = linearLayoutManager.findFirstCompletelyVisibleItemPosition();
if (firstVisiblePosition == 0) {
mAppBarLayout.setExpanded(true, true);
}
}
}
});

You can fully expand or collapse the App Bar with the setExpanded() method. One implementation could involve overriding dispatchTouchEvent() in your Activity class, and auto-collapsing/expanding your App Bar based on whether it is collapsed past the halfway point:
#Override
public boolean dispatchTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
float per = Math.abs(mAppBarLayout.getY()) / mAppBarLayout.getTotalScrollRange();
boolean setExpanded = (per <= 0.5F);
mAppBarLayout.setExpanded(setExpanded, true);
}
return super.dispatchTouchEvent(event);
}
In respect to automatically scrolling to the last position on a fling, I have put some code on GitHub that shows how to programmatically smooth scroll to a specific location that may help. Calling a scroll to list.size() - 1 on a fling for instance could replicate the behaviour. Parts of this code by the way are adapted from the StylingAndroid and Novoda blogs:
public class RecyclerLayoutManager extends LinearLayoutManager {
private AppBarManager mAppBarManager;
private int visibleHeightForRecyclerView;
public RecyclerLayoutManager(Context context) {
super(context);
}
#Override
public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {
View firstVisibleChild = recyclerView.getChildAt(0);
final int childHeight = firstVisibleChild.getHeight();
int distanceInPixels = ((findFirstVisibleItemPosition() - position) * childHeight);
if (distanceInPixels == 0) {
distanceInPixels = (int) Math.abs(firstVisibleChild.getY());
}
//Called Once
if (visibleHeightForRecyclerView == 0) {
visibleHeightForRecyclerView = mAppBarManager.getVisibleHeightForRecyclerViewInPx();
}
//Subtract one as adapter position 0 based
final int visibleChildCount = visibleHeightForRecyclerView/childHeight - 1;
if (position <= visibleChildCount) {
//Scroll to the very top and expand the app bar
position = 0;
mAppBarManager.expandAppBar();
} else {
mAppBarManager.collapseAppBar();
}
SmoothScroller smoothScroller = new SmoothScroller(recyclerView.getContext(), Math.abs(distanceInPixels), 1000);
smoothScroller.setTargetPosition(position);
startSmoothScroll(smoothScroller);
}
public void setAppBarManager(AppBarManager appBarManager) {
mAppBarManager = appBarManager;
}
private class SmoothScroller extends LinearSmoothScroller {
private static final int TARGET_SEEK_SCROLL_DISTANCE_PX = 10000;
private final float distanceInPixels;
private final float duration;
public SmoothScroller(Context context, int distanceInPixels, int duration) {
super(context);
this.distanceInPixels = distanceInPixels;
float millisecondsPerPx = calculateSpeedPerPixel(context.getResources().getDisplayMetrics());
this.duration = distanceInPixels < TARGET_SEEK_SCROLL_DISTANCE_PX ?
(int) (Math.abs(distanceInPixels) * millisecondsPerPx) : duration;
}
#Override
public PointF computeScrollVectorForPosition(int targetPosition) {
return RecyclerLayoutManager.this
.computeScrollVectorForPosition(targetPosition);
}
#Override
protected int calculateTimeForScrolling(int dx) {
float proportion = (float) dx / distanceInPixels;
return (int) (duration * proportion);
}
}
}
Edit:
AppBarManager in the above code snippet refers to an interface used to communicate with the AppBarLayout in an Activity. Collapse/expand app bar methods do just that, with animations. The final method is used to calculate the number of RecyclerView rows visible on screen:
AppBarManager.java
public interface AppBarManager {
void collapseAppBar();
void expandAppBar();
int getVisibleHeightForRecyclerViewInPx();
}
MainActivity.java
public class MainActivity extends AppCompatActivity implements AppBarManager{
#Override
public void collapseAppBar() {
mAppBarLayout.setExpanded(false, true);
}
#Override
public void expandAppBar() {
mAppBarLayout.setExpanded(true, true);
}
#Override
public int getVisibleHeightForRecyclerViewInPx() {
if (mRecyclerFragment == null) mRecyclerFragment =
(RecyclerFragment) getSupportFragmentManager().findFragmentByTag(RecyclerFragment.TAG);
int windowHeight, appBarHeight, headerViewHeight;
windowHeight = getWindow().getDecorView().getHeight();
appBarHeight = mAppBarLayout.getHeight();
headerViewHeight = mRecyclerFragment.getHeaderView().getHeight();
return windowHeight - (appBarHeight + headerViewHeight);
}

How to make the Floating Action Button scroll off the screen or disappear

I've seen some apps with a RecyclerView and a Floating Action Button and when you scroll down the RecyclerView the Floating Action Button will scroll off from the bottom or just minimize and disappear. I have created a RecyclerView and a FloatingActionButton in a CoordinatorLayout using the design support library. But the FloatingActionButton doesn't do anything when I scroll. Is there a way to add an attribute in the layout XML file to achieve this, or can I write some Java codes to do this? And how?

for doing this you have to create custom RecyclerView.OnScrollListener class..
here is what I did.
public abstract class HidingScrollListener extends
RecyclerView.OnScrollListener {
private static final int HIDE_THRESHOLD = 20;
private int scrolledDistance = 0;
private boolean controlsVisible = true;
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (scrolledDistance > HIDE_THRESHOLD && controlsVisible) {
onHide();
controlsVisible = false;
scrolledDistance = 0;
} else if (scrolledDistance < -HIDE_THRESHOLD && !controlsVisible) {
onShow();
controlsVisible = true;
scrolledDistance = 0;
}
if ((controlsVisible && dy > 0) || (!controlsVisible && dy < 0)) {
scrolledDistance += dy;
}
}
public abstract void onHide();
public abstract void onShow();
And in your MainActivity
rv.setOnScrollListener(new HidingScrollListener() {
#Override
public void onShow() {
fam.animate().translationY(0)
.setInterpolator(new DecelerateInterpolator(2)).start();
}
#Override
public void onHide() {
RelativeLayout.LayoutParams lp = (RelativeLayout.LayoutParams) fam
.getLayoutParams();
int fabMargin = lp.bottomMargin;
fam.animate().translationY(fam.getHeight() + fabMargin)
.setInterpolator(new AccelerateInterpolator(2)).start();
}
});
Where rv would be your RecyclerView and fam would be your FAB.
Hope it will help you.

How to animate FloatingActionButton like in Google+ app for Android?

I set FloatingActionButton to bottom of screen and I want to animate the button.
Hidden when scrolling down
Shown when scrolling up
Like google implemented it in their Google+ app.
I think CoordinatorLayout and AppBarLayout is needed but how to implement it to use it with the FloatingActionButton?

You can achieve it using the default FloatingActionButton changing its
default Behavior using the app:layout_behavior attribute:
You can use a layout like:
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:layout_scrollFlags="scroll|enterAlways" />
</android.support.design.widget.AppBarLayout>
// Your layout, for example a RecyclerView
<RecyclerView
.....
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end|bottom"
android:layout_margin="#dimen/fab_margin"
android:src="#drawable/ic_done"
app:layout_behavior="com.support.android.designlibdemo.ScrollAwareFABBehavior" />
</android.support.design.widget.CoordinatorLayout>
With the app:layout_behavior you can define your own Behavior. With the onStartNestedScroll() and onNestedScroll() methods you can interact with scroll events.
You can use a Behavior like this.
You can find the original code here:
public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
private boolean mIsAnimatingOut = false;
public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
super();
}
#Override
public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
final View directTargetChild, final View target, final int nestedScrollAxes) {
// Ensure we react to vertical scrolling
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL
|| super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
}
#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 && !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);
}
}
// Same animation that FloatingActionButton.Behavior uses to hide the FAB when the AppBarLayout exits
private void animateOut(final FloatingActionButton button) {
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(button).scaleX(0.0F).scaleY(0.0F).alpha(0.0F).setInterpolator(INTERPOLATOR).withLayer()
.setListener(new ViewPropertyAnimatorListener() {
public void onAnimationStart(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = true;
}
public void onAnimationCancel(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
}
public void onAnimationEnd(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
view.setVisibility(View.GONE);
}
}).start();
} else {
Animation anim = AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_out);
anim.setInterpolator(INTERPOLATOR);
anim.setDuration(200L);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = true;
}
public void onAnimationEnd(Animation animation) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
button.setVisibility(View.GONE);
}
#Override
public void onAnimationRepeat(final Animation animation) {
}
});
button.startAnimation(anim);
}
}
// Same animation that FloatingActionButton.Behavior uses to show the FAB when the AppBarLayout enters
private void animateIn(FloatingActionButton button) {
button.setVisibility(View.VISIBLE);
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(button).scaleX(1.0F).scaleY(1.0F).alpha(1.0F)
.setInterpolator(INTERPOLATOR).withLayer().setListener(null)
.start();
} else {
Animation anim = AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_in);
anim.setDuration(200L);
anim.setInterpolator(INTERPOLATOR);
button.startAnimation(anim);
}
}
}

As of this post, there are no methods that will automatically handle hiding and showing the FloatingActionButton in the Design Support Libraries. I know this because this was my first assignment at work.
The methods you are thinking of are used to animate the FloatingActionButton up and down when a Snackbar is created, and yes, that will work if you are using a CoordinatorLayout.
Here's my code. It's based off of this repo. It has listeners for RecyclerView and AbsListView that handle animating the button automatically. You can either do
button.show();
or
button.hide();
to hide the button manually, or you can call:
button.attachToListView(listView);
and
button.attachToRecyclerView(recyclerView);
and it will hide on scroll down and show on scroll up with no further code.
Hope this helps!
AnimatedFloatingActionButton:
public class AnimatedFloatingActionButton extends FloatingActionButton
{
private static final int TRANSLATE_DURATION_MILLIS = 200;
private final Interpolator mInterpolator = new AccelerateDecelerateInterpolator();
private boolean mVisible;
public AnimatedFloatingActionButton(Context context, AttributeSet attrs)
{
super(context, attrs);
Log.i("Abscroll", "mVisible" + mVisible);
}
public void show() {
show(true);
}
public void hide() {
hide(true);
}
public void show(boolean animate) {
toggle(true, animate, false);
}
public void hide(boolean animate) {
toggle(false, animate, false);
}
private void toggle(final boolean visible, final boolean animate, boolean force) {
if (mVisible != visible || force) {
mVisible = visible;
int height = getHeight();
if (height == 0 && !force) {
ViewTreeObserver vto = getViewTreeObserver();
if (vto.isAlive()) {
vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
ViewTreeObserver currentVto = getViewTreeObserver();
if (currentVto.isAlive()) {
currentVto.removeOnPreDrawListener(this);
}
toggle(visible, animate, true);
return true;
}
});
return;
}
}
int translationY = visible ? 0 : height + getMarginBottom();
Log.i("Abscroll", "transY" + translationY);
if (animate) {
this.animate().setInterpolator(mInterpolator)
.setDuration(TRANSLATE_DURATION_MILLIS)
.translationY(translationY);
} else {
setTranslationY(translationY);
}
}
}
private int getMarginBottom() {
int marginBottom = 0;
final ViewGroup.LayoutParams layoutParams = getLayoutParams();
if (layoutParams instanceof ViewGroup.MarginLayoutParams) {
marginBottom = ((ViewGroup.MarginLayoutParams) layoutParams).bottomMargin;
}
return marginBottom;
}
public void attachToListView(#NonNull AbsListView listView)
{
listView.setOnScrollListener(new AbsListViewScrollDetector() {
#Override
void onScrollUp() {
hide();
}
#Override
void onScrollDown() {
show();
}
#Override
void setScrollThreshold() {
setScrollThreshold(getResources().getDimensionPixelOffset(R.dimen.fab_scroll_threshold));
}
});
}
public void attachToRecyclerView(#NonNull RecyclerView recyclerView) {
recyclerView.addOnScrollListener(new RecyclerViewScrollDetector() {
#Override
void onScrollUp() {
hide();
}
#Override
void onScrollDown() {
show();
}
#Override
void setScrollThreshold() {
setScrollThreshold(getResources().getDimensionPixelOffset(R.dimen.fab_scroll_threshold));
}
});
}
}
AbsListViewScrollDetector:
abstract class AbsListViewScrollDetector implements AbsListView.OnScrollListener {
private int mLastScrollY;
private int mPreviousFirstVisibleItem;
private AbsListView mListView;
private int mScrollThreshold;
abstract void onScrollUp();
abstract void onScrollDown();
abstract void setScrollThreshold();
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
if(totalItemCount == 0) return;
if (isSameRow(firstVisibleItem)) {
int newScrollY = getTopItemScrollY();
boolean isSignificantDelta = Math.abs(mLastScrollY - newScrollY) > mScrollThreshold;
Log.i("Abscroll", "mLastScrollY " + mLastScrollY);
Log.i("Abscroll", "newScrollY " + newScrollY);
if (isSignificantDelta) {
Log.i("Abscroll", "sig delta");
if (mLastScrollY > newScrollY) {
onScrollUp();
Log.i("Abscroll", "sig delta up");
} else {
onScrollDown();
Log.i("Abscroll", "sig delta down");
}
}
mLastScrollY = newScrollY;
} else {
if (firstVisibleItem > mPreviousFirstVisibleItem) {
onScrollUp();
Log.i("Abscroll", "prev up");
} else {
onScrollDown();
Log.i("Abscroll", "prev down");
}
mLastScrollY = getTopItemScrollY();
mPreviousFirstVisibleItem = firstVisibleItem;
}
}
public void setScrollThreshold(int scrollThreshold) {
mScrollThreshold = scrollThreshold;
Log.i("Abscroll", "LView thresh " + scrollThreshold);
}
public void setListView(#NonNull AbsListView listView) {
mListView = listView;
}
private boolean isSameRow(int firstVisibleItem) {
return firstVisibleItem == mPreviousFirstVisibleItem;
}
private int getTopItemScrollY() {
if (mListView == null || mListView.getChildAt(0) == null) return 0;
View topChild = mListView.getChildAt(0);
return topChild.getTop();
}
}
RecyclerViewScrollDetector:
abstract class RecyclerViewScrollDetector extends RecyclerView.OnScrollListener {
private int mScrollThreshold;
abstract void onScrollUp();
abstract void onScrollDown();
abstract void setScrollThreshold();
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
boolean isSignificantDelta = Math.abs(dy) > mScrollThreshold;
if (isSignificantDelta) {
if (dy > 0) {
onScrollUp();
Log.i("Abscroll", "Rview up");
} else {
onScrollDown();
Log.i("Abscroll", "RView down");
}
}
}
public void setScrollThreshold(int scrollThreshold) {
mScrollThreshold = scrollThreshold;
Log.i("Abscroll", "RView thresh " + scrollThreshold);
}
}

Googles Design Support Library will do that.
Try to implement this code to your layout file:
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_add_black"
android:layout_gravity="bottom|end"
app:elevation="6dp"
app:pressedTranslationZ="12dp"/>
It's important that you add compile 'com.android.support:design:22.2.0' to your build.gradle. If you're using eclipse there is another way to add this library to your project.
Important resources:
Design Support Library (II): Floating Action Button
Android Design Support Library
Google Releasing A FABulous New Design Support Library [Updated]

ExtendedFloatingActionButton enough to achieve your goal, no need to handle any logic code, just extend() and shrink() on scrolling
Full example:
<?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">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton
android:id="#+id/extendedFloatingButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end|bottom"
android:text="Reorder List"
android:layout_margin="12dp"
app:icon="#drawable/ic_reorder" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
And in your code:
recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
override fun onScrollStateChanged(recyclerView: RecyclerView, newState:
Int) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
extendedFloatingButton.extend()
}
super.onScrollStateChanged(recyclerView, newState)
}
override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
if (dy > 0 || dy < 0 && extendedFloatingButton.isExtended) {
extendedFloatingButton.shrink()
}
}
})