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.ViewGroup;
  import android.view.animation.AccelerateDecelerateInterpolator;
  
  /**
   * This animation causes the view to flip vertically by a customizable number of
   * degrees and at a customizable pivot point.
   * 
   * @author SiYao
   * 
   */
  public class FlipVerticalAnimation extends Animation implements Combinable {
  
  	public static final int PIVOT_CENTER = 0, PIVOT_TOP = 1, PIVOT_BOTTOM = 2;
  
  	float degrees;
  	int pivot;
  	TimeInterpolator interpolator;
  	long duration;
  	AnimationListener listener;
  
  	/**
  	 * This animation causes the view to flip vertically by a customizable
  	 * number of degrees and at a customizable pivot point.
  	 * 
  	 * @param view
  	 *            The view to be animated.
  	 */
  	public FlipVerticalAnimation(View view) {
  		this.view = view;
  		degrees = 360;
  		pivot = PIVOT_CENTER;
  		interpolator = new AccelerateDecelerateInterpolator();
  		duration = DURATION_LONG;
  		listener = null;
  	}
  
  	@Override
  	public void animate() {
  		getAnimatorSet().start();
  	}
  
  	@Override
  	public AnimatorSet getAnimatorSet() {
  		ViewGroup parentView = (ViewGroup) view.getParent(), rootView = (ViewGroup) view
  				.getRootView();
  		while (parentView != rootView) {
  			parentView.setClipChildren(false);
  			parentView = (ViewGroup) parentView.getParent();
  		}
  		rootView.setClipChildren(false);
  
  		float pivotX, pivotY, viewWidth = view.getWidth(), viewHeight = view
  				.getHeight();
  		switch (pivot) {
  		case PIVOT_TOP:
  			pivotX = viewWidth / 2;
  			pivotY = 0f;
  			break;
  		case PIVOT_BOTTOM:
  			pivotX = viewWidth / 2;
  			pivotY = viewHeight;
  			break;
  		default:
  			pivotX = viewWidth / 2;
  			pivotY = viewHeight / 2;
  			break;
  		}
  		view.setPivotX(pivotX);
  		view.setPivotY(pivotY);
  
  		AnimatorSet flipSet = new AnimatorSet();
  		flipSet.play(ObjectAnimator.ofFloat(view, View.ROTATION_X,
  				view.getRotationX() + degrees));
  		flipSet.setInterpolator(interpolator);
  		flipSet.setDuration(duration);
  		flipSet.addListener(new AnimatorListenerAdapter() {
  
  			@Override
  			public void onAnimationEnd(Animator animation) {
  				if (getListener() != null) {
  					getListener().onAnimationEnd(FlipVerticalAnimation.this);
  				}
  			}
  		});
  		return flipSet;
  	}
  
  	/**
  	 * @return The number of degrees to flip by.
  	 */
  	public float getDegrees() {
  		return degrees;
  	}
  
  	/**
  	 * In order to flip down, the number of degrees should be negative and vice
  	 * versa.
  	 * 
  	 * @param degrees
  	 *            The number of degrees to set to flip by.
  	 * @return This object, allowing calls to methods in this class to be
  	 *         chained.
  	 */
  	public FlipVerticalAnimation setDegrees(float degrees) {
  		this.degrees = degrees;
  		return this;
  	}
  
  	/**
  	 * The available pivot points are <code>PIVOT_CENTER</code>,
  	 * <code>PIVOT_TOP</code> and <code>PIVOT_BOTTOM</code>.
  	 * 
  	 * @return The pivot point for flipping.
  	 */
  	public int getPivot() {
  		return pivot;
  	}
  
  	/**
  	 * The available pivot points are <code>PIVOT_CENTER</code>,
  	 * <code>PIVOT_TOP</code> and <code>PIVOT_BOTTOM</code>.
  	 * 
  	 * @param pivot
  	 *            The pivot point to set for flipping.
  	 * @return This object, allowing calls to methods in this class to be
  	 *         chained.
  	 */
  	public FlipVerticalAnimation setPivot(int pivot) {
  		this.pivot = pivot;
  		return this;
  	}
  
  	/**
  	 * @return The interpolator of the entire animation.
  	 */
  	public TimeInterpolator getInterpolator() {
  		return interpolator;
  	}
  
  	/**
  	 * @param interpolator
  	 *            The interpolator of the entire animation to set.
  	 */
  	public FlipVerticalAnimation 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.
  	 * @return This object, allowing calls to methods in this class to be
  	 *         chained.
  	 */
  	public FlipVerticalAnimation 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.
  	 * @return This object, allowing calls to methods in this class to be
  	 *         chained.
  	 */
  	public FlipVerticalAnimation setListener(AnimationListener listener) {
  		this.listener = listener;
  		return this;
  	}
  
  }
  