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

Question

I set FloatingActionButton to bottom of screen and I want to animate the button.

• Hidden when scrolling down
• Shown when scrolling up

Lik

Answer 1

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);
}
}