FlippingView.java

/*
 * Copyright 2012 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.examples.youtubeapidemo.ui;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.DecelerateInterpolator;
import android.widget.FrameLayout;
import android.widget.ImageView;

/**
 * A view which flips from one ImageView to another view using a 3D flip animation.
 */
public class FlippingView extends FrameLayout {

  private final ImageView flipOutView;
  private final ImageView flipInView;
  private final AnimatorSet animations;
  private final Listener listener;

  /**
   * Defines an interface to enable listening to flip events.
   */
  public interface Listener {

    /**
     * Called when the FlippingView has completed a flip.
     *
     * @param view The FlippingView which has completed the flip.
     */
    void onFlipped(FlippingView view);

  }

  /**
   * Create a flipping view which performs a 3D flip animation from one view to another.
   *
   * @param context The context associated with this View.
   * @param listener A listener which is informed of when the view has completed flipping.
   * @param width The view's width.
   * @param height The view's height.
   */
  public FlippingView(Context context, Listener listener, int width, int height) {
    super(context);

    this.listener = listener;
    this.flipOutView = new ImageView(context);
    this.flipInView = new ImageView(context);

    addView(flipOutView, width, height);
    addView(flipInView, width, height);

    flipInView.setRotationY(-90);

    ObjectAnimator flipOutAnimator = ObjectAnimator.ofFloat(flipOutView, "rotationY", 0, 90);
    flipOutAnimator.setInterpolator(new AccelerateInterpolator());
    Animator flipInAnimator = ObjectAnimator.ofFloat(flipInView, "rotationY", -90, 0);
    flipInAnimator.setInterpolator(new DecelerateInterpolator());
    animations = new AnimatorSet();
    animations.playSequentially(flipOutAnimator, flipInAnimator);
    animations.addListener(new AnimationListener());
  }

  public void setFlipInDrawable(Drawable drawable) {
    flipInView.setImageDrawable(drawable);
  }

  public void setFlipOutDrawable(Drawable drawable) {
    flipOutView.setImageDrawable(drawable);
  }

  public void setFlipDuration(int flipDuration) {
    animations.setDuration(flipDuration);
  }

  public void flip() {
    animations.start();
  }

  /**
   * Listens to the end of the flip animation to signal to listeners that the flip is complete
   */
  public final class AnimationListener extends AnimatorListenerAdapter {

    @Override
    public void onAnimationEnd(Animator animation) {
      flipOutView.setRotationY(0);
      flipInView.setRotationY(-90);
      listener.onFlipped(FlippingView.this);
    }
  }

}