Make circular reveal animations on a fragment

activity_main.xml

<LinearLayout
    android:id="@+id/container"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity"
    tools:ignore="MergeRootFrame">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="addFragment"
        android:text="Add fragment" />

</LinearLayout>

CircularRevealingFragment.java

/**
     * Our demo fragment
     */
    public static class CircularRevealingFragment extends Fragment {

        OnFragmentTouched listener;

        public CircularRevealingFragment() {
        }

        public static CircularRevealingFragment newInstance(int centerX, int centerY, int color) {
            Bundle args = new Bundle();
            args.putInt("cx", centerX);
            args.putInt("cy", centerY);
            args.putInt("color", color);
            CircularRevealingFragment fragment = new CircularRevealingFragment();
            fragment.setArguments(args);
            return fragment;

        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);

            rootView.setBackgroundColor(getArguments().getInt("color"));

            // To run the animation as soon as the view is layout in the view hierarchy we add this
            // listener and remove it
            // as soon as it runs to prevent multiple animations if the view changes bounds
            rootView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
                @Override
                public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop,
                        int oldRight, int oldBottom) {
                    v.removeOnLayoutChangeListener(this);
                    int cx = getArguments().getInt("cx");
                    int cy = getArguments().getInt("cy");

                    // get the hypothenuse so the radius is from one corner to the other
                    int radius = (int) Math.hypot(right, bottom);

                    Animator reveal = ViewAnimationUtils.createCircularReveal(v, cx, cy, 0, radius);
                    reveal.setInterpolator(new DecelerateInterpolator(2f));
                    reveal.setDuration(1000);
                    reveal.start();
                }
            });

            // attach a touch listener
            rootView.setOnTouchListener(new View.OnTouchListener() {
                @Override
                public boolean onTouch(View v, MotionEvent event) {
                    if (listener != null) {
                        listener.onFragmentTouched(CircularRevealingFragment.this, event.getX(), event.getY());
                    }
                    return true;
                }
            });
            return rootView;
        }

        @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
            if (activity instanceof OnFragmentTouched) {
                listener = (OnFragmentTouched) activity;
            }
        }

        /**
         * Get the animator to unreveal the circle
         *
         * @param cx center x of the circle (or where the view was touched)
         * @param cy center y of the circle (or where the view was touched)
         * @return Animator object that will be used for the animation
         */
        public Animator prepareUnrevealAnimator(float cx, float cy) {
            int radius = getEnclosingCircleRadius(getView(), (int) cx, (int) cy);
            Animator anim = ViewAnimationUtils.createCircularReveal(getView(), (int) cx, (int) cy, radius, 0);
            anim.setInterpolator(new AccelerateInterpolator(2f));
            anim.setDuration(1000);
            return anim;
        }

        /**
         * To be really accurate we have to start the circle on the furthest corner of the view
         *
         * @param v  the view to unreveal
         * @param cx center x of the circle
         * @param cy center y of the circle
         * @return the maximum radius
         */
        private int getEnclosingCircleRadius(View v, int cx, int cy) {
            int realCenterX = cx + v.getLeft();
            int realCenterY = cy + v.getTop();
            int distanceTopLeft = (int) Math.hypot(realCenterX - v.getLeft(), realCenterY - v.getTop());
            int distanceTopRight = (int) Math.hypot(v.getRight() - realCenterX, realCenterY - v.getTop());
            int distanceBottomLeft = (int) Math.hypot(realCenterX - v.getLeft(), v.getBottom() - realCenterY);
            int distanceBottomRight = (int) Math.hypot(v.getRight() - realCenterX, v.getBottom() - realCenterY);

            Integer[] distances = new Integer[]{distanceTopLeft, distanceTopRight, distanceBottomLeft,
                    distanceBottomRight};

            return Collections.max(Arrays.asList(distances));
        }
    }

fragment_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="200dp" android:layout_margin="16dp" tools:context=".MainActivity$PlaceholderFragment"
    >

    <TextView android:text="Touch me to hide me!" android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</RelativeLayout>

MainActivity.java

public class MainActivity extends Activity implements OnFragmentTouched {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void addFragment(View v) {
        int randomColor =
                Color.argb(255, (int) (Math.random() * 255), (int) (Math.random() * 255), (int) (Math.random() * 255));
        Fragment fragment = CircularRevealingFragment.newInstance(20, 20, randomColor);
        getFragmentManager().beginTransaction().add(R.id.container, fragment).commit();
    }

    @Override
    public void onFragmentTouched(Fragment fragment, float x, float y) {
        if (fragment instanceof CircularRevealingFragment) {
            final CircularRevealingFragment theFragment = (CircularRevealingFragment) fragment;

            Animator unreveal = theFragment.prepareUnrevealAnimator(x, y);

            unreveal.addListener(new Animator.AnimatorListener() {
                @Override
                public void onAnimationStart(Animator animation) {
                }

                @Override
                public void onAnimationEnd(Animator animation) {
                    // remove the fragment only when the animation finishes
                    getFragmentManager().beginTransaction().remove(theFragment).commit();
                    //to prevent flashing the fragment before removing it, execute pending transactions inmediately
                    getFragmentManager().executePendingTransactions();
                }

                @Override
                public void onAnimationCancel(Animator animation) {
                }

                @Override
                public void onAnimationRepeat(Animator animation) {
                }
            });
            unreveal.start();
        }
    }

OnFragmentTouched.java

package com.fernandofgallego.circularrevealfragment.sample;

import android.app.Fragment;

/**
 * Created by fernando.gallego on 11/11/14.
 */
public interface OnFragmentTouched {
    public void onFragmentTouched(Fragment fragment, float x, float y);
}