Android GestureDetector实现手势滑动效果

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  tools:context=".MainActivity" >   <ImageView    android:id="@+id/ivShow"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:src="@drawable/ic_launcher" /> </RelativeLayout>

package com.example.gesturedetector; import android.os.Bundle;import android.app.Activity;import android.util.Log;import android.view.GestureDetector;import android.view.GestureDetector.SimpleOnGestureListener;import android.view.Menu;import android.view.MotionEvent;import android.view.View;import android.view.View.OnTouchListener;import android.widget.ImageView;import android.widget.Toast; public class MainActivity extends Activity {  private ImageView ivShow; private GestureDetector gestureDetector;  class myGestureListener extends SimpleOnGestureListener{ @Override /*识别滑动，第一个参数为刚开始事件，第二个参数为结束事件*/ public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,  float velocityY) {  if(e1.getX()-e2.getX()>50){  Toast.makeText(MainActivity.this,"从右往左滑动"+(e1.getX()-e2.getX()),Toast.LENGTH_LONG).show();  }else if(e2.getX()-e1.getX()>50){  Toast.makeText(MainActivity.this,"从左往右滑动"+(e2.getX()-e1.getX()),Toast.LENGTH_LONG).show();  }  return super.onFling(e1, e2, velocityX, velocityY); } } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);  gestureDetector=new GestureDetector(MainActivity.this,new myGestureListener());  ivShow=(ImageView) findViewById(R.id.ivShow); ivShow.setLongClickable(true); //view必须设置为true，否则手势识别无法正确工作 ivShow.setOnTouchListener(new OnTouchListener() {     /*可以捕获到触摸屏幕发生的Event事件*/  @Override  public boolean onTouch(View arg0, MotionEvent event) {  gestureDetector.onTouchEvent(event);//转发  return false;  } }); }}