This example depends on Support Library 23.4.0.+.

BottomSheetBehavior is characterized by :

1. Two toolbars with animations that respond to the bottom sheet movements.
2. A FAB that hides when it is near to the “modal toolbar” (the one that appears when you are sliding up).
3. A backdrop image behind bottom sheet with some kind of parallax effect.
4. A Title (TextView) in Toolbar that appears when bottom sheet reach it.
5. The notification satus bar can turn its background to transparent or full color.
6. A custom bottom sheet behavior with an “anchor” state.

Now let’s check them one by one:

ToolBars When you open that view in Google Maps, you can see a toolbar in where you can search, it’s the only one that I’m not doing exactly like Google Maps, because I wanted to do it more generic. Anyway that ToolBar is inside an AppBarLayout and it got hidden when you start dragging the BottomSheet and it appears again when the BottomSheet reach the COLLAPSED state. To achieve it you need to:

• create a Behavior and extend it from AppBarLayout.ScrollingViewBehavior
• override layoutDependsOn and onDependentViewChanged methods. Doing it you will listen for bottomSheet movements.
• create some methods to hide and unhide the AppBarLayout/ToolBar with animations.

This is how I did it for first toolbar or ActionBar:

@Override
public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
    return dependency instanceof NestedScrollView;
}

@Override
public boolean onDependentViewChanged(CoordinatorLayout parent, View child,
                                      View dependency) {

    if (mChild == null) {
        initValues(child, dependency);
        return false;
    }

    float dVerticalScroll = dependency.getY() - mPreviousY;
    mPreviousY = dependency.getY();

    //going up
    if (dVerticalScroll <= 0 && !hidden) {
        dismissAppBar(child);
        return true;
    }

    return false;
}

private void initValues(final View child, View dependency) {

    mChild = child;
    mInitialY = child.getY();

    BottomSheetBehaviorGoogleMapsLike bottomSheetBehavior = BottomSheetBehaviorGoogleMapsLike.from(dependency);
    bottomSheetBehavior.addBottomSheetCallback(new BottomSheetBehaviorGoogleMapsLike.BottomSheetCallback() {
        @Override
        public void onStateChanged(@NonNull View bottomSheet, @BottomSheetBehaviorGoogleMapsLike.State int newState) {
            if (newState == BottomSheetBehaviorGoogleMapsLike.STATE_COLLAPSED ||
                    newState == BottomSheetBehaviorGoogleMapsLike.STATE_HIDDEN)
                showAppBar(child);
        }

        @Override
        public void onSlide(@NonNull View bottomSheet, float slideOffset) {

        }
    });
}

private void dismissAppBar(View child){
    hidden = true;
    AppBarLayout appBarLayout = (AppBarLayout)child;
    mToolbarAnimation = appBarLayout.animate().setDuration(mContext.getResources().getInteger(android.R.integer.config_shortAnimTime));
    mToolbarAnimation.y(-(mChild.getHeight()+25)).start();
}

private void showAppBar(View child) {
    hidden = false;
    AppBarLayout appBarLayout = (AppBarLayout)child;
    mToolbarAnimation = appBarLayout.animate().setDuration(mContext.getResources().getInteger(android.R.integer.config_mediumAnimTime));
    mToolbarAnimation.y(mInitialY).start();
}

Here is the complete file if you need it

The second Toolbar or “Modal” toolbar: You have to override the same methods, but in this one you have to take care of more behaviors:

• show/hide the ToolBar with animations
• change status bar color/background
• show/hide the BottomSheet title in the ToolBar