GestureDetector學習之左右滑動，上下滑動屏幕切換頁面

要實現滑屏等觸發事件，視情況而定；

如果實現的觸屏或者手勢效果較多，則使用第一種方法，實現OnGestureListener 接口（參考OnGestureListener）；

如果只是實現較少的效果，則考慮使用SimpleOnGestureListener（參考SimpleOnGestureListenter）;主要分爲以下三步：

第一種方法：

1、繼承OnTouchListener , OnGestureListener ；

//繼承OnTouchListener,OnGestureListener
public class MainActivity extends Activity implements OnTouchListener,OnGestureListener{

注：此處使用的OnGestureListener來自包 android.view.GestureDetector.OnGestureListener;而不是 android.gesture.GestureOverlayView.OnGestureListener;

2、初始化OnGestureListener ，即註冊手勢監聽 ；獲得當前接受操作的佈局id ； 註冊觸屏監聽；

//手勢監聽
mGestureDetector = new GestureDetector(MainActivity.this,(OnGestureListener) this);//(OnGestureListener) 可以省略
//獲得當前接受操作的佈局id
RelativeLayout mActivity = (RelativeLayout)findViewById(R.id.main_activity);
//觸屏監聽
mActivity.setOnTouchListener(this);
mActivity.setLongClickable(true);

3、重載onFling()和onTouch();

public boolean onTouch(View v, MotionEvent event) {
	return mGestureDetector.onTouchEvent(event);
}
	
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        //省略
}

第二種方法如下：

1、繼承OnTouchListener  ；

//繼承OnTouchListener
public class MainActivity extends Activity implements OnTouchListener{

2、初始化OnGestureListener ，即註冊手勢監聽 ；獲得當前接受操作的佈局id ； 註冊觸屏監聽；

//手勢監聽
mGestureDetector = new GestureDetector(MainActivity.this,new MySimpleOnGestureListener());//下邊定義MySimpleOnGestureListener,
                                                                                          //並使其繼承SimpleOnGestureListener類
//獲得當前接受操作的佈局id
RelativeLayout mActivity = (RelativeLayout)findViewById(R.id.main_activity);
//觸屏監聽
mActivity.setOnTouchListener(this);
mActivity.setLongClickable(true);

3、定義SimpleOnGestureListener子類，並重載onTouch()和所需方法;

class MySimpleGestureListener extends SimpleOnGestureListener{
		@Override 
		public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
			
			//大於設定的最小滑動距離並且在水平/豎直方向速度絕對值大於設定的最小速度，則執行相應方法
			if(e1.getX()-e2.getX() > verticalMinistance && Math.abs(velocityX) > minVelocity){
	    		Toast.makeText(MainActivity.this, "turn left", Toast.LENGTH_SHORT).show();
		    		
		    }else if(e2.getX() - e1.getX() > verticalMinistance && Math.abs(velocityX) > minVelocity){
	    		Toast.makeText(MainActivity.this, "turn right", Toast.LENGTH_SHORT).show();
	    		
		    }else if(e1.getY()-e2.getY() > 20 && Math.abs(velocityY) > 10){
		    	Toast.makeText(MainActivity.this, "turn up", Toast.LENGTH_SHORT).show();
		    	
		    }else if(e2.getY()-e1.getY() > 20 && Math.abs(velocityY) > 10){
		    	Toast.makeText(MainActivity.this, "turn down", Toast.LENGTH_SHORT).show();
		    }
	    	
	    	return false;
	    }
		
	     @Override
	     public boolean onDown(MotionEvent e){
		Toast.makeText(MainActivity.this, "onDown", Toast.LENGTH_SHORT).show();
		return false;
	     }
	}

具體代碼如下：

（第一種方法）

import android.app.Activity;
import android.content.Intent;

import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
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.*;

public class MainActivity extends Activity implements OnTouchListener,OnGestureListener{
        private static final String tag = "mainActivity";
	
	private GestureDetector mGestureDetector;
	private int verticalMinistance = 20;	        //水平最小識別距離
	private int minVelocity = 10;			//最小識別速度
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        //手勢監聽
        mGestureDetector = new GestureDetector(MainActivity.this,(OnGestureListener) this);//(OnGestureListener) 可以省略
        //獲得當前接受操作的佈局id
        RelativeLayout mActivity = (RelativeLayout)findViewById(R.id.main_activity);
        //觸屏監聽
        mActivity.setOnTouchListener(this);
        mActivity.setLongClickable(true);
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

	@Override
	public boolean onTouch(View v, MotionEvent event) {
		return mGestureDetector.onTouchEvent(event);
	}
	
	public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
		
	     //大於設定的最小滑動距離並且在水平/豎直方向速度絕對值大於設定的最小速度，則執行相應方法
	    if(e1.getX()-e2.getX() > verticalMinistance && Math.abs(velocityX) > minVelocity){
                //在此處實現跳轉
                //Intent intent  = new Intent(MainActivity.this,nextActivity.class);
    		//startActivity(intent);
               
    		Toast.makeText(MainActivity.this, "turn left", Toast.LENGTH_SHORT).show();
	    		
	    }else if(e2.getX() - e1.getX() > verticalMinistance && Math.abs(velocityX) > minVelocity){
    		Toast.makeText(MainActivity.this, "turn right", Toast.LENGTH_SHORT).show();
    		
	    }else if(e1.getY()-e2.getY() > 20 && Math.abs(velocityY) > 10){
	    	Toast.makeText(MainActivity.this, "turn up", Toast.LENGTH_SHORT).show();
	    	
	    }else if(e2.getY()-e1.getY() > 20 && Math.abs(velocityY) > 10){
	    	Toast.makeText(MainActivity.this, "turn down", Toast.LENGTH_SHORT).show();
	    }
	    	
	    return false;
	}

	//只要有觸發就會調用次方法
	@Override
	public boolean onDown(MotionEvent e) {
		Toast.makeText(MainActivity.this, "onDown", Toast.LENGTH_SHORT).show();
		return false;
	}

	@Override
	public void onLongPress(MotionEvent e) {
		Toast.makeText(MainActivity.this, "onLongPress", Toast.LENGTH_SHORT).show();
		
	}

	@Override
	public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
		
//		Toast.makeText(MainActivity.this, "onScroll", Toast.LENGTH_SHORT).show();
		return false;
	}


	@Override
	public void onShowPress(MotionEvent e) {
//		Toast.makeText(MainActivity.this, "onShowPress", Toast.LENGTH_SHORT).show();
	}

	@Override
	public boolean onSingleTapUp(MotionEvent e) {
//		Toast.makeText(MainActivity.this, "onsingleTapup", Toast.LENGTH_SHORT).show();
		return false;
	}	  
}

（第二種方法）

import android.app.Activity;
import android.content.Intent;

import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
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.*;

public class MainActivity extends Activity implements OnTouchListener{
	private static final String tag = "mainActivity";
	
	private GestureDetector mGestureDetector;
	private int verticalMinistance = 20;	        //水平最小識別距離
	private int minVelocity = 10;			//最小識別速度
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        //手勢監聽
        mGestureDetector = new GestureDetector(MainActivity.this,new LearnGestureListener());
        //獲得當前接受操作的佈局id
        RelativeLayout mActivity = (RelativeLayout)findViewById(R.id.main_activity);
        //觸屏監聽
        mActivity.setOnTouchListener(this);
        mActivity.setLongClickable(true);
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

	@Override
	public boolean onTouch(View v, MotionEvent event) {
		return mGestureDetector.onTouchEvent(event);
	}
	
	class LearnGestureListener extends SimpleOnGestureListener{
		@Override 
		public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
			
			//大於設定的最小滑動距離並且在水平/豎直方向速度絕對值大於設定的最小速度，則執行相應方法
			if(e1.getX()-e2.getX() > verticalMinistance && Math.abs(velocityX) > minVelocity){
	    		Toast.makeText(MainActivity.this, "turn left", Toast.LENGTH_SHORT).show();
		    		
		    }else if(e2.getX() - e1.getX() > verticalMinistance && Math.abs(velocityX) > minVelocity){
	    		Toast.makeText(MainActivity.this, "turn right", Toast.LENGTH_SHORT).show();
	    		
		    }else if(e1.getY()-e2.getY() > 20 && Math.abs(velocityY) > 10){
		    	Toast.makeText(MainActivity.this, "turn up", Toast.LENGTH_SHORT).show();
		    	
		    }else if(e2.getY()-e1.getY() > 20 && Math.abs(velocityY) > 10){
		    	Toast.makeText(MainActivity.this, "turn down", Toast.LENGTH_SHORT).show();
		    }
	    	
	    	return false;
	    }
		
		@Override
		public boolean onDown(MotionEvent e){
			Toast.makeText(MainActivity.this, "onDown", Toast.LENGTH_SHORT).show();
			return false;
		}
	}
 
}