Android手势识别

GestureDetector —— 手势识别类

sdk源代码：

public class GestureDetector {

public interface OnGestureListener {

boolean onDown(MotionEvent e);

void onShowPress(MotionEvent e);

boolean onSingleTapUp(MotionEvent e);

boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY);

void onLongPress(MotionEvent e);

boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY);
}

public interface OnDoubleTapListener {

boolean onSingleTapConfirmed(MotionEvent e);

boolean onDoubleTap(MotionEvent e);

boolean onDoubleTapEvent(MotionEvent e);
}

SimpleOnGestureListener

/**
* A convenience class to extend when you only want to listen for a subset
* of all the gestures. This implements all methods in the
* {@link OnGestureListener} and {@link OnDoubleTapListener} but does
* nothing and return {@code false} for all applicable methods.
*/

//touch down后又没有滑动（onScroll），又没有长按（onLongPress），然后Touchup时触发
public boolean onSingleTapUp(MotionEvent e) {
return false;
}

public void onLongPress(MotionEvent e) {
}

public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY) {
return false;
}

//Touch了滑动一点距离后，up时触发
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
return false;
}

//Touch了还没有滑动时触发
public void onShowPress(MotionEvent e) {
}

//Touch down时触发
public boolean onDown(MotionEvent e) {
return false;
}

//双击的第二下Touch down时触发
public boolean onDoubleTap(MotionEvent e) {
return false;
}

//双击的第二下Touch down和up都会触发，可用e.getAction()区分。
public boolean onDoubleTapEvent(MotionEvent e) {
return false;
}

//touch down后又没有滑动（onScroll），又没有长按（onLongPress），然后Touchup时触发
public boolean onSingleTapConfirmed(MotionEvent e) {
return false;
}
}

点击一下非常快的（不滑动）Touchup：

onDown->onSingleTapUp->onSingleTapConfirmed

点击一下稍微慢点的（不滑动）Touchup：

onDown->onShowPress->onSingleTapUp->onSingleTapConfirmed

部分示例代码：

GestureDetector detector new GestureDetector(this, new SimpleOnGestureListener() {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2,
float velocityX, float velocityY) {
if(Math.abs(e2.getRawY() - e1.getRawY()) > 100) {
return true;
}

if(e2.getRawX() - e1.getRawX() > 200) {
//显示上一个页面，从左往右滑动
showLast();
return true;

}
if(e1.getRawX() - e2.getRawX() > 200) {
//显示下一个页面，从右往左滑动
showNext();
return true;
}
return super.onFling(e1, e2, velocityX, velocityY);

}

});

使用GestureDetector需要在View中重写onTouchEvent事件。

@Override
public boolean onTouchEvent(MotionEvent event) {
detector.onTouchEvent(event);
return super.onTouchEvent(event);
}