CircularReveal backport

ClipRevealFrame

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Path;
import android.util.AttributeSet;
import android.widget.FrameLayout;

public class ClipRevealFrame extends FrameLayout{

    private Path mRevealPath;

    boolean mClipOutlines;
    float mCenterX;
    float mCenterY;
    float mRadius;

    public ClipRevealFrame(Context context) {
        super(context);
        init();
    }

    public ClipRevealFrame(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public ClipRevealFrame(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init(){
        mRevealPath = new Path();
        mClipOutlines = false;
    }

    public void setClipOutLines(boolean shouldClip){
        mClipOutlines = shouldClip;
    }

    public void setClipCenter(final int x, final int y){
        mCenterX = x;
        mCenterY = y;
    }

    public void setClipRadius(final float radius){
        mRadius = radius;
        invalidate();
    }

    @Override
    public void draw(Canvas canvas) {
        if(!mClipOutlines){
            super.draw(canvas);
            return;
        }
        final int state = canvas.save();
        mRevealPath.reset();
        mRevealPath.addCircle(mCenterX, mCenterY, mRadius, Path.Direction.CW);
        canvas.clipPath(mRevealPath);
        super.draw(canvas);
        canvas.restoreToCount(state);
    }
}

usage

        private Animator createCheckoutRevealAnimator(final ClipRevealFrame view, int x, int y, float startRadius, float endRadius) {

            final Animator reveal;
            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP){
               reveal = ViewAnimationUtils.createCircularReveal(view, x, y, startRadius, endRadius);
            } else {
                view.setClipOutLines(true);
                view.setClipCenter(x, y);
                reveal = ObjectAnimator.ofFloat(view, "ClipRadius", startRadius, endRadius);
                reveal.addListener(new Animator.AnimatorListener() {
                    @Override
                    public void onAnimationStart(Animator animation) {

                    }

                    @Override
                    public void onAnimationEnd(Animator animation) {
                        view.setClipOutLines(false);
                    }

                    @Override
                    public void onAnimationCancel(Animator animation) {

                    }

                    @Override
                    public void onAnimationRepeat(Animator animation) {

                    }
                });
            }
            reveal.setDuration(500);
            return reveal;
        }

    }

Is there a sample project?

No but I'll try to put one together.

It doesn't work for me for 4.1-4.3. View just reveals itself at once

It was fun to debug. onDraw was never called. Modifying init to this fixes it:

private void init(){
    mRevealPath = new Path();
    mClipOutlines = false;
    setWillNotDraw(false);
}

P.S. Great gist