Android 用手势切换activity

package rw.gest;    import android.app.Activity;  import android.content.Intent;  import android.os.Bundle;  import android.view.GestureDetector;  import android.view.GestureDetector.OnGestureListener;  import android.view.MotionEvent;  import android.view.View;  import android.view.View.OnTouchListener;  import android.widget.LinearLayout;  import android.widget.Toast;  public class Gest01Activity extends Activity{            GestureDetector detector;      public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.main);          detector=new GestureDetector(new GestureListener());          LinearLayout layout=(LinearLayout)findViewById(R.id.linearlayout);          layout.setOnTouchListener(new TouhListener());          layout.setLongClickable(true);                }  //触摸屏幕监听   class TouhListener implements OnTouchListener{      @Override    public boolean onTouch(View v, MotionEvent event) {     // TODO Auto-generated method stub     Toast.makeText(getApplicationContext(), "----?", event.getAction()).show();     return detector.onTouchEvent(event);    }       }   //手势滑动监听   class GestureListener implements OnGestureListener{      @Override    public boolean onDown(MotionEvent e) {     // TODO Auto-generated method stub    /*     * 当触摸屏幕是使用这个函数     */     Toast.makeText(getApplicationContext(), "-----------> onDown", Toast.LENGTH_LONG).show();     return false;    }      @Override    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,      float velocityY) {     // e1 触摸的起始位置，e2 触摸的结束位置，velocityX X轴每一秒移动的像素速度（大概这个意思） velocityY 就是Ｙ咯     //手势左,上为正 ——，右，下为负正     if (e2.getX()-e1.getX()>50) {      //为什么是50？ 这个根据你的模拟器大小来定，看看模拟器宽度，e2.getX()-e1.getX()<屏幕宽度就ＯＫ      Toast.makeText(getApplicationContext(), "向右滑动", Toast.LENGTH_LONG).show();      //要触发什么事件都在这里写就OK       //如果要跳转到另外一个activity      Intent intent=new Intent(Gest01Activity.this, toActivity.class);      startActivity(intent);     }     if (Math.abs(e2.getX()-e1.getX())>50) {      Toast.makeText(getApplicationContext(), "向左滑动", Toast.LENGTH_LONG).show();     }     if (Math.abs(e2.getY()-e1.getY())>50) {      Toast.makeText(getApplicationContext(), "向上滑动", Toast.LENGTH_LONG).show();     }     if (e2.getY()-e1.getY()>50) {      Toast.makeText(getApplicationContext(), "向下滑动", Toast.LENGTH_LONG).show();     }     return false;    }      @Override    public void onLongPress(MotionEvent e) {     // TODO Auto-generated method stub\      /*       * 长按事件  一切长事件按屏幕想要触发的事件都在这里写       */     Toast.makeText(getApplicationContext(), "------------> onLongPress", Toast.LENGTH_LONG).show();    }      @Override    public boolean onScroll(MotionEvent e1, MotionEvent e2,      float distanceX, float distanceY) {     // TODO Auto-generated method stub     /*      * 这个函数大概是这样，英语差了，有误差。distanceX 是X轴路径长度，distanceY 是Y轴路径长度（注意：是路径，不是位移）;      */     Toast.makeText(getApplicationContext(), "------------> onScroll", Toast.LENGTH_LONG).show();     return false;    }      @Override    public void onShowPress(MotionEvent e) {     // TODO Auto-generated method stub     /*      *       */     Toast.makeText(getApplicationContext(), "------------> onShowPress", Toast.LENGTH_LONG).show();    }      @Override    public boolean onSingleTapUp(MotionEvent e) {     // TODO Auto-generated method stub     Toast.makeText(getApplicationContext(), "------------> onSingleTapUp", Toast.LENGTH_LONG).show();     return false;    }       }  }

<?xml version="1.0" encoding="utf-8"?>  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"           android:orientation="vertical"      android:layout_width="fill_parent"      android:layout_height="fill_parent"       android:id="@+id/linearlayout"      >    <ImageView android:src="@drawable/eight" android:id="@+id/imageView1" android:layout_height="match_parent" android:layout_width="match_parent"></ImageView>  </LinearLayout>