如何通过GestureDetector实现屏幕事件监听(滑动切换Layout)

内容如题: 
1.SlideExample.java文件 

package com.example;

import android.app.Activity;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ViewGroup;

public class SlideExample extends Activity {

    public ViewGroup container1, container2;

    private GestureDetector gestureDetector;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // 监听屏幕动作事件
        SampleGuest gestureListener = new SampleGuest(this);
        gestureDetector = new GestureDetector(gestureListener);

        container1 = (ViewGroup) findViewById(R.id.container1);
        container2 = (ViewGroup) findViewById(R.id.container2);
    }

    // called automatically, any screen action will Triggered it
    public boolean onTouchEvent(MotionEvent event) {
        if (gestureDetector.onTouchEvent(event))
            return true;
        else
            return false;
    }

}

2.SampleGuest.java文件 

package com.example;

import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.GestureDetector.OnGestureListener;
import android.view.animation.AnimationUtils;

public class SampleGuest implements OnGestureListener {

    SlideExample se;

    private static final int SWIPE_MAX_OFF_PATH = 100;

    private static final int SWIPE_MIN_DISTANCE = 100;

    private static final int SWIPE_THRESHOLD_VELOCITY = 100;

    public SampleGuest(SlideExample se) {
        this.se = se;
    }

    // 用户轻触触摸屏，由1个MotionEvent ACTION_DOWN触发
    public boolean onDown(MotionEvent e) {
        Log.d("TAG", "[onDown]");
        return true;
    }

    // 用户按下触摸屏、快速移动后松开,由1个MotionEvent ACTION_DOWN,
    // 多个ACTION_MOVE, 1个ACTION_UP触发
    // e1：第1个ACTION_DOWN MotionEvent
    // e2：最后一个ACTION_MOVE MotionEvent
    // velocityX：X轴上的移动速度，像素/秒
    // velocityY：Y轴上的移动速度，像素/秒
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {
        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) {
            se.container1.setAnimation(AnimationUtils.loadAnimation(se,
                    R.anim.push_left_out));
            se.container2.setVisibility(View.VISIBLE);
            se.container2.setAnimation(AnimationUtils.loadAnimation(se,
                    R.anim.push_right_in));
            se.container1.setVisibility(View.GONE);

        } else if ((e2.getX() - e1.getX()) > SWIPE_MIN_DISTANCE
                && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
            se.container1.setVisibility(View.VISIBLE);
            se.container1.setAnimation(AnimationUtils.loadAnimation(se,
                    R.anim.push_left_in));
            se.container2.setAnimation(AnimationUtils.loadAnimation(se,
                    R.anim.push_right_out));
            se.container2.setVisibility(View.GONE);
        }
        return true;
    }

    // 用户长按触摸屏，由多个MotionEvent ACTION_DOWN触发
    public void onLongPress(MotionEvent e) {
        Log.d("TAG", "[onLongPress]");
    }

    // 用户按下触摸屏，并拖动，由1个MotionEvent ACTION_DOWN, 多个ACTION_MOVE触发
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
            float distanceY) {
        Log.d("TAG", "[onScroll]");
        return true;
    }

    // 用户轻触触摸屏，尚未松开或拖动，由一个1个MotionEvent ACTION_DOWN触发
    // 注意和onDown()的区别，强调的是没有松开或者拖动的状态
    public void onShowPress(MotionEvent e) {
        Log.d("TAG", "[onShowPress]");

    }

    // 用户（轻触触摸屏后）松开，由一个1个MotionEvent ACTION_UP触发
    public boolean onSingleTapUp(MotionEvent e) {
        Log.d("TAG", "[onSingleTapUp]");
        return true;
    }

}

3.main.xml文件 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:id="@+id/container">

    <RelativeLayout android:layout_width="fill_parent"
        android:id="@+id/container1" android:layout_height="fill_parent"
        android:visibility="visible">
        <ImageView android:layout_width="fill_parent"
            android:layout_height="fill_parent" android:background="@drawable/one" />
    </RelativeLayout>

    <RelativeLayout android:layout_width="fill_parent"
        android:background="@drawable/gray" android:id="@+id/container2"
        android:visibility="gone" android:layout_height="fill_parent">
        <ImageView android:layout_width="fill_parent"
            android:layout_height="fill_parent" android:background="@drawable/three" />
    </RelativeLayout>

</RelativeLayout>

4.程序所用到的anim中的几个xml文件内容 
push_left_in.xml 

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromXDelta="-100%p"
               android:toXDelta="0"
               android:duration="1000"/>
    <alpha android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="100" />
</set>

push_left_out.xml 

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromXDelta="0" android:toXDelta="-100%p"
        android:duration="1000" />
    <alpha android:fromAlpha="1.0" android:toAlpha="1.0"
        android:duration="400" />
</set>

push_right_in.xml 

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromXDelta="100%p"
               android:toXDelta="0"
               android:duration="1000"/>
    <alpha android:fromAlpha="1.0" android:toAlpha="1.0" android:duration="400" />
</set>

push_right_out.xml 

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromXDelta="0"
               android:toXDelta="100%p"
               android:duration="1000"/>
    <alpha android:fromAlpha="1.0" android:toAlpha="1.0" android:duration="400" />
</set>

6.至于程序中所用到的图片,大家可以自己找几张,修改名称即可