Android ViewFlipper 的施用

package com.iaiai;import android.app.Activity;import android.os.Bundle;import android.view.GestureDetector;import android.view.GestureDetector.SimpleOnGestureListener;import android.view.MotionEvent;import android.view.animation.Animation;import android.view.animation.AnimationUtils;import android.widget.ViewFlipper;/** *  * <p> * Title: MainActivity.java * </p> * <p> * E-Mail: [email protected] * </p> * <p> * QQ: 176291935 * </p> * <p> * Http: iaiai.iteye.com * </p> * <p> * Create time: 2011-10-24 * </p> *  * @author 丸子 * @version 0.0.1 */public class MainActivity extends Activity {	private ViewFlipper viewFlipper;	private GestureDetector gestureDetector;	private Animation slideLeftIn;      private Animation slideLeftOut;      private Animation slideRightIn;      private Animation slideRightOut;	private class GestureDetectorListener extends SimpleOnGestureListener {		private static final int SWIPE_MIN_DISTANCE = 120;		private static final int SWIPE_MAX_OFF_PATH = 250;		private static final int SWIPE_THRESHOLD_VELOCITY = 200;				@Override		public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,				float velocityY) {			try {				if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)					return false;				if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE						&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {					viewFlipper.setInAnimation(slideLeftIn);                      viewFlipper.setOutAnimation(slideLeftOut);					viewFlipper.showNext();				} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE						&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {					viewFlipper.setInAnimation(slideRightIn);                      viewFlipper.setOutAnimation(slideRightOut);					viewFlipper.showPrevious();				}			} catch (Exception e) {				// nothing			}			return false;		}	}	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.main);				slideLeftIn = AnimationUtils.loadAnimation(this, R.anim.slide_left_in);        slideLeftOut = AnimationUtils.loadAnimation(this, R.anim.slide_left_out);        slideRightIn = AnimationUtils.loadAnimation(this, R.anim.slide_right_in);        slideRightOut = AnimationUtils.loadAnimation(this, R.anim.slide_right_out);		viewFlipper = (ViewFlipper) findViewById(R.id.viewFlipper);		gestureDetector = new GestureDetector(new GestureDetectorListener());	}	@Override	public boolean onTouchEvent(MotionEvent event) {		return gestureDetector.onTouchEvent(event);	}}