初学Android,手势翻页效果(四十九)

下面是一个利用手势功能做的一个翻页效果

上图实际是一个ViewFlipper容器，里面放了5张图片，从右向左划动，看下一张图片，从左向右划动，看上一张图片

同时在划动时播放动画(缩放和透明度的改变)，这样看起来更生动一些

动画文件

left_in.xml，图片从右向左滑动时的动画,View进入屏幕时候使用的动画

left_out.xml l，图片从右向左滑动时的动画, View退出屏幕时候使用的动画

向右划动的动画类似，不写出来了

package WangLi.IO.GestureFlip;

import android.app.Activity;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
import android.widget.ViewFlipper;

public class GestureFlip extends Activity 
      implements OnGestureListener
{
	//ViewFlipper实例
	ViewFlipper flipper;
	//定义手势检测器实例
	GestureDetector detector;
	//定义一个动画数组,用于为ViewFlipper指定切换动画效果
	Animation[] animations = new Animation[4];
	//定义手势动作两点之间的最小距离
	final int FLIP_DISTANCE = 50;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //创建手势检测器
        detector = new GestureDetector(this);
        //获得ViewFlipper实例
        flipper = (ViewFlipper)this.findViewById(R.id.flipper);
        //为ViewFlipper添加5个ImageView组件
        flipper.addView(addImageView(R.drawable.one));
        flipper.addView(addImageView(R.drawable.two));
        flipper.addView(addImageView(R.drawable.three));
        flipper.addView(addImageView(R.drawable.four));
        flipper.addView(addImageView(R.drawable.five));
        //初始化Animation数组
        animations[0] = AnimationUtils.loadAnimation(this, R.anim.left_in);
        animations[1] = AnimationUtils.loadAnimation(this, R.anim.left_out);
        animations[2] = AnimationUtils.loadAnimation(this, R.anim.right_in);
        animations[3] = AnimationUtils.loadAnimation(this, R.anim.right_out);
    }
	private View addImageView(int resId) {
		// TODO Auto-generated method stub
		ImageView imageView = new ImageView(this);
		imageView.setImageResource(resId);
		imageView.setScaleType(ImageView.ScaleType.CENTER);
		return imageView;
	}
	@Override
	public boolean onDown(MotionEvent arg0) {
		// TODO Auto-generated method stub
		return false;
	}
	@Override
	public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX,
			float velocityY) {
		// TODO Auto-generated method stub
		//如果第一触点事件的x坐标大于第二个触点事件的x坐标超过FLIP_DISTANCE
		//也就是手势从右向左滑动
		if(event1.getX() - event2.getX() > FLIP_DISTANCE)
		{
			//为flipper设置切换的动画效果
			flipper.setInAnimation(animations[0]);
			flipper.setOutAnimation(animations[1]);
			flipper.showPrevious();
			return true;
		}
		
		if(event2.getX() - event1.getX() > FLIP_DISTANCE)
		{
			//为flipper设置切换的动画效果
			flipper.setInAnimation(animations[2]);
			flipper.setOutAnimation(animations[3]);
			flipper.showNext();
			return true;
		}
		return false;
	}
	@Override
	public boolean onTouchEvent(MotionEvent event)
	{
		//将该Activity上的触碰事件交给GestureDetector处理
		return detector.onTouchEvent(event);
	}
	@Override
	public void onLongPress(MotionEvent arg0) {
		// TODO Auto-generated method stub
		
	}
	@Override
	public boolean onScroll(MotionEvent arg0, MotionEvent arg1, float arg2,
			float arg3) {
		// TODO Auto-generated method stub
		return false;
	}
	@Override
	public void onShowPress(MotionEvent arg0) {
		// TODO Auto-generated method stub
		
	}
	@Override
	public boolean onSingleTapUp(MotionEvent arg0) {
		// TODO Auto-generated method stub
		return false;
	}
}