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);
}
@Override
public 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;
}
@Override
public boolean onDown(MotionEvent e) {
return false;
}
@Override
public void onLongPress(MotionEvent e) {
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY) {
return false;
}
@Override
public void onShowPress(MotionEvent e) {
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
return false;
}
}
使用方法如下：
public class TestActivity extends Activity {
private GestureHelper gh;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_start);
gh = new GestureHelper(this);
gh.setOnFlingListener(new OnFlingListener() {
@Override
public void OnFlingLeft() {
//向左滑动
}
@Override
public void OnFlingRight() {
//向右滑动
}
});
}
@Override
public boolean onTouchEvent(MotionEvent event) {
return gh.onTouchEvent(event);
}
}
