FlipAnimator.java

package com.aincc.lib.ui.anim;

import android.graphics.Camera;
import android.graphics.Matrix;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Animation;
import android.view.animation.Transformation;

/**
 * 
 * <h3><b>FlipAnimator</b></h3></br>
 * 
 * @author aincc@barusoft.com
 * @version 1.0.0
 * @since 1.0.0
 */
public class FlipAnimator extends Animation
{
	private Camera camera;
	private View fromView;
	private View toView;
	private float centerX;
	private float centerY;
	private boolean forward = true;
	private boolean visibilitySwapped;

	/**
	 * 
	 * @since 1.0.0
	 * @param fromView
	 * @param toView
	 * @param centerX2
	 * @param centerY2
	 */
	public FlipAnimator(View fromView, View toView, float centerX2, float centerY2)
	{
		this.fromView = fromView;
		this.toView = toView;
		this.centerX = centerX2;
		this.centerY = centerY2;

		setDuration(500);
		setFillAfter(true);
		setInterpolator(new AccelerateDecelerateInterpolator());
	}

	/**
	 * 
	 * @since 1.0.0
	 */
	public void reverse()
	{
		forward = false;
		View tmp = toView;
		toView = fromView;
		fromView = tmp;
	}

	@Override
	public void initialize(int width, int height, int parentWidth, int parentHeight)
	{
		super.initialize(width, height, parentWidth, parentHeight);
		camera = new Camera();
	}

	@Override
	protected void applyTransformation(float interpolatedTime, Transformation t)
	{
		// Angle around the y-axis of the rotation at the given time. It is
		// calculated both in radians and in the equivalent degrees.
		final double radians = Math.PI * interpolatedTime;
		float degrees = (float) (180.0 * radians / Math.PI);

		// Once we reach the midpoint in the animation, we need to hide the
		// source view and show the destination view. We also need to change
		// the angle by 180 degrees so that the destination does not come in
		// flipped around. This is the main problem with SDK sample, it does not
		// do this.
		if (interpolatedTime >= 0.5f)
		{
			degrees -= 180.f;

			if (!visibilitySwapped)
			{
				fromView.setVisibility(View.GONE);
				toView.setVisibility(View.VISIBLE);

				visibilitySwapped = true;
			}
		}

		if (forward)
		{
			degrees = -degrees;
		}

		final Matrix matrix = t.getMatrix();

		camera.save();
		camera.translate(0.0f, 0.0f, (float) (150.0 * Math.sin(radians)));
		camera.rotateY(degrees);
		camera.getMatrix(matrix);
		camera.restore();

		matrix.preTranslate(-centerX, -centerY);
		matrix.postTranslate(centerX, centerY);
	}
}