How to implement Custom Collapsable Toolbar in android?

The AppBarComponentprovides a method called .setExpanded(boolean expanded), which allows you to expand your AppBarComponent.

But keep in mind, that this method relies on this layout being a direct child of a CoordinatorLayout.

You can read this for more information.

If you want to animate to a custom offset, try using the setTopAndBottomOffset(int) method.

CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) appBar.getLayoutParams();final AppBarLayout.Behavior behavior = (AppBarLayout.Behavior) params.getBehavior();if (behavior != null) {    ValueAnimator valueAnimator = ValueAnimator.ofInt();    valueAnimator.setInterpolator(new DecelerateInterpolator());    valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {        @Override        public void onAnimationUpdate(ValueAnimator animation) {            behavior.setTopAndBottomOffset((Integer) animation.getAnimatedValue());            appBar.requestLayout();        }    });    valueAnimator.setIntValues(0, -900);    valueAnimator.setDuration(400);    valueAnimator.start();}