Circular reveal transition for new activity

Question

As per https://developer.android.com/training/material/animations.html

The ViewAnimationUtils.createCircularReveal() method enables you t

Answer 1

After looking for a solution for half a day without a result, I came up with an own implementation. I'm using a transparent activity with a matching root layout. The root layout is a view which can then be revealed with createCircularReveal().

My code looks like this:

Theme Definition in styles.xml

Activity Definition in AndroidManifest.xml

then I declared a layout for my activity (I've chosen DrawerLayout, so that I can have a NavDrawer. Every layout should work here.)

Important is the FrameLayout with the id root_layout. This view will be revealed in the activity.

Finally I implemented CircularRevealActivity and overwrote onCreate():

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    overridePendingTransition(R.anim.do_not_move, R.anim.do_not_move);

    setContentView(R.layout.activity_reveal_circular);

    if (savedInstanceState == null) {
        rootLayout.setVisibility(View.INVISIBLE);

        ViewTreeObserver viewTreeObserver = rootLayout.getViewTreeObserver();
        if (viewTreeObserver.isAlive()) {
            viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                @Override
                public void onGlobalLayout() {
                    circularRevealActivity();
                    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
                        rootLayout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
                    } else {
                        rootLayout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                    } 
                }
            });
        }
    }
}

It was important to put circularRevealActivity() into a OnGlobalLayoutListener, because the view needs to be drawn for the animation.

circularRevealActivity() looks like Ishaan's proposal:

private void circularRevealActivity() {

    int cx = rootLayout.getWidth() / 2;
    int cy = rootLayout.getHeight() / 2;

    float finalRadius = Math.max(rootLayout.getWidth(), rootLayout.getHeight());

    // create the animator for this view (the start radius is zero)
    Animator circularReveal = ViewAnimationUtils.createCircularReveal(rootLayout, cx, cy, 0, finalRadius);
    circularReveal.setDuration(1000);

    // make the view visible and start the animation
    rootLayout.setVisibility(View.VISIBLE);
    circularReveal.start();
}

Edit 1

The definition for R.anim.do_not_move was added. However, it should work without that line too, if your design does not specify default transitions for activities. Let me know

R.anim.do_not_move: