content: package com.rsen.github.easyandroidanimations;
  
  import android.animation.Animator;
  import android.animation.AnimatorListenerAdapter;
  import android.animation.AnimatorSet;
  import android.animation.ObjectAnimator;
  import android.animation.TimeInterpolator;
  import android.view.View;
  import android.view.animation.AccelerateDecelerateInterpolator;
  
  /**
   * This animation fades the view out by animating its alpha property to 0. On
   * animation end, the view is restored to its original state and is set to
   * <code>View.INVISIBLE</code>.
   * 
   * @author SiYao
   * 
   */
  public class FadeOutAnimation extends Animation implements Combinable {
  
  	TimeInterpolator interpolator;
  	long duration;
  	AnimationListener listener;
  
  	/**
  	 * This animation fades the view out by animating its alpha property to 0.
  	 * On animation end, the view is restored to its original state and is set
  	 * to <code>View.INVISIBLE</code>.
  	 * 
  	 * @param view
  	 *            The view to be animated.
  	 */
  	public FadeOutAnimation(View view) {
  		this.view = view;
  		interpolator = new AccelerateDecelerateInterpolator();
  		duration = DURATION_LONG;
  		listener = null;
  	}
  
  	@Override
  	public void animate() {
  		getAnimatorSet().start();
  	}
  
  	@Override
  	public AnimatorSet getAnimatorSet() {
  		final float originalAlpha = view.getAlpha();
  		AnimatorSet fadeSet = new AnimatorSet();
  		fadeSet.play(ObjectAnimator.ofFloat(view, View.ALPHA, 0f));
  		fadeSet.setInterpolator(interpolator);
  		fadeSet.setDuration(duration);
  		fadeSet.addListener(new AnimatorListenerAdapter() {
  
  			@Override
  			public void onAnimationEnd(Animator animation) {
  				view.setVisibility(View.INVISIBLE);
  				view.setAlpha(originalAlpha);
  				if (getListener() != null) {
  					getListener().onAnimationEnd(FadeOutAnimation.this);
  				}
  			}
  		});
  		return fadeSet;
  	}
  
  	/**
  	 * @return The interpolator of the entire animation.
  	 */
  	public TimeInterpolator getInterpolator() {
  		return interpolator;
  	}
  
  	/**
  	 * @param interpolator
  	 *            The interpolator of the entire animation to set.
  	 */
  	public FadeOutAnimation setInterpolator(TimeInterpolator interpolator) {
  		this.interpolator = interpolator;
  		return this;
  	}
  
  	/**
  	 * @return The duration of the entire animation.
  	 */
  	public long getDuration() {
  		return duration;
  	}
  
  	/**
  	 * @param duration
  	 *            The duration of the entire animation to set.
  	 */
  	public FadeOutAnimation setDuration(long duration) {
  		this.duration = duration;
  		return this;
  	}
  
  	/**
  	 * @return The listener for the end of the animation.
  	 */
  	public AnimationListener getListener() {
  		return listener;
  	}
  
  	/**
  	 * @param listener
  	 *            The listener to set for the end of the animation.
  	 */
  	public FadeOutAnimation setListener(AnimationListener listener) {
  		this.listener = listener;
  		return this;
  	}
  
  }
  