android 上下左右手势判断 根据别人的改的

GestureUtils.java

package com.gesture;

import android.content.Context;
import android.util.DisplayMetrics;
import android.view.WindowManager;

public class GestureUtils {

    //获取屏幕的大小
    public static Screen getScreenPix(Context context) {
        DisplayMetrics dm = new DisplayMetrics();
        WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        windowManager.getDefaultDisplay().getMetrics(dm);
        return new Screen(dm.widthPixels,dm.heightPixels);
    }

    public static class Screen{

        public int widthPixels;
        public int heightPixels;

        public Screen(){

        }

        public Screen(int widthPixels,int heightPixels){
            this.widthPixels=widthPixels;
            this.heightPixels=heightPixels;
        }

        @Override
        public String toString() {
            return "("+widthPixels+","+heightPixels+")";
        }

    }

}

　　BuileGestureExt.java

package com.gesture;

import com.gesture.GestureUtils.Screen;

import android.content.Context;
import android.view.GestureDetector;
import android.view.MotionEvent;

public class  BuileGestureExt  {
    public static final int GESTURE_UP=0;
    public static final int GESTURE_DOWN=1;
    public static final int GESTURE_LEFT=2;
    public static final int GESTURE_RIGHT=3;
    private OnGestureResult onGestureResult;
    private Context mContext;
    public BuileGestureExt(Context c,OnGestureResult onGestureResult) {
        this.mContext=c;
        this.onGestureResult=onGestureResult;
        screen = GestureUtils.getScreenPix(c);
    }
    public GestureDetector Buile()
    {
        return new GestureDetector(mContext, onGestureListener);
    }

    private Screen screen;
    private GestureDetector.OnGestureListener onGestureListener = new GestureDetector.SimpleOnGestureListener(){

        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                float velocityY) {
            float x = e2.getX() - e1.getX();
            float y = e2.getY() - e1.getY();
            //限制必须得划过屏幕的1/4才能算划过
            float x_limit = screen.widthPixels / 4;
            float y_limit = screen.heightPixels / 4;
            float x_abs = Math.abs(x);
            float y_abs = Math.abs(y);
            if(x_abs >= y_abs){
                //gesture left or right
                if(x > x_limit || x < -x_limit){
                    if(x>0){
                        //right
                        doResult(GESTURE_RIGHT); 
                    }else if(x<=0){
                        //left
                        doResult(GESTURE_LEFT); 
                    }
                }
            }else{
                //gesture down or up
                if(y > y_limit || y < -y_limit){
                    if(y>0){
                        //down                        doResult(GESTURE_DOWN);                     }else if(y<=0){                        //up                        doResult(GESTURE_UP);                     }                }            }            return true;        }            };    public void doResult(int result)    {        if(onGestureResult!=null)        {            onGestureResult.onGestureResult(result);        }    }        public interface OnGestureResult    {        public void onGestureResult(int direction);    }}

　　demo

package com.gesture;

 

import android.app.Activity;

import android.os.Bundle;

import android.view.GestureDetector;

import android.view.MotionEvent;

import android.widget.Toast;

 

public class GesturetestActivity extends Activity {

    /** Called when the activity is first created. */

 

    private GestureDetector gestureDetector; 

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        gestureDetector = new BuileGestureExt(this,new BuileGestureExt.OnGestureResult() {

            @Override

            public void onGestureResult(int direction) {

                show(Integer.toString(direction));

            }

        }

        ).Buile();

    }

 

    @Override

    public boolean onTouchEvent(MotionEvent event) {

        return gestureDetector.onTouchEvent(event);

    }

    private void show(String value){

        Toast.makeText(this, value, Toast.LENGTH_SHORT).show();

    }

 

     

}