Android手势识别简单封装类

今天在做一个项目时用到了简单的手势功能(向左，向右滑切屏)，于是简单地封装了下

import android.content.Context;import android.util.DisplayMetrics;import android.view.GestureDetector;import android.view.GestureDetector.OnGestureListener;import android.view.MotionEvent;public class GestureHelper implements OnGestureListener {private GestureDetector gesture_detector;private int screen_width;private OnFlingListener listener_onfling;public static abstract class OnFlingListener {public abstract void OnFlingLeft();public abstract void OnFlingRight();}public GestureHelper(Context context) {        DisplayMetrics dm = context.getResources().getDisplayMetrics();        screen_width = dm.widthPixels;        gesture_detector = new GestureDetector(context, this);}public void setOnFlingListener(OnFlingListener listener) {listener_onfling = listener;}public boolean onTouchEvent(MotionEvent event) {return gesture_detector.onTouchEvent(event);}@Overridepublic boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {// 触发条件 ：// X轴的坐标位移大于FLING_MIN_DISTANCE，且移动速度大于FLING_MIN_VELOCITY个像素/秒final int FLING_MIN_DISTANCE = (int) (screen_width / 3.0f), FLING_MIN_VELOCITY = 200;if (e1.getX() - e2.getX() > FLING_MIN_DISTANCE && Math.abs(velocityX) > FLING_MIN_VELOCITY) {listener_onfling.OnFlingLeft();} else if (e2.getX() - e1.getX() > FLING_MIN_DISTANCE && Math.abs(velocityX) > FLING_MIN_VELOCITY) {listener_onfling.OnFlingRight();}return true;}@Overridepublic boolean onDown(MotionEvent e) {return false;}@Overridepublic void onLongPress(MotionEvent e) {}@Overridepublic boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,float distanceY) {return false;}@Overridepublic void onShowPress(MotionEvent e) {}@Overridepublic boolean onSingleTapUp(MotionEvent e) {return false;}}

使用方法如下：

public class TestActivity extends Activity {private GestureHelper gh;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_start);gh = new GestureHelper(this);gh.setOnFlingListener(new OnFlingListener() {@Overridepublic void OnFlingLeft() {//向左滑动}@Overridepublic void OnFlingRight() {//向右滑动}});}@Overridepublic boolean onTouchEvent(MotionEvent event) {return gh.onTouchEvent(event);}}

诸如向上向下滑等因为需求不多所以没有加上去，有需求的朋友可以自己加上。