[英]Ontouch event of OnTouchListener gets called twice in android
[英]OnTouch method of OnTouchListener subclass being called many times in Android
我在简单的Android应用程序中创建了一个简单的[View.OnTouchListener][1]
实现。
我现在的目标是使其能够向下滑动。 例如,如果我向下滑动,则希望它检测到我已经这样做了。
它可以成功完成此操作,但是,每次向下滑动,其他时间也会被调用。 我可以看到这是由于onTouch
方法switch语句中的默认行为:
这是MySwipeListener :
public class MySwipeListener implements View.OnTouchListener{
private Activity activity;
public MySwipeListener(Activity activity){
this.activity = activity;
}
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
switch (motionEvent.getAction()){
case MotionEvent.ACTION_DOWN: {
Log.i("MotionEvent", "Action Down!");
Toast.makeText(activity, "Motion Down", Toast.LENGTH_LONG);
return true;
}
default: {
Log.i("MotionEvent", "Other Action!");
Toast.makeText(activity, "Other Action", Toast.LENGTH_LONG);
return true;
}
}
}
}
这就是我在MainActivity
使用它的方式:
Button topUp = (Button) findViewById(R.id.a);
topUp.setOnTouchListener(new MySwipeListener(this));
当我在Android屏幕上实际滑动时,会得到如下结果:
09-16 16:39:48.276 26748-26748/mobi.corp.proj I/MotionEvent﹕ Action Down!
09-16 16:39:48.316 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.326 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.346 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.361 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.376 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.396 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.411 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.426 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.446 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.461 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.476 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.496 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.511 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.526 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.546 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.561 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.576 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.596 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.611 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.626 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.631 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.886 26748-26748/mobi.corp.proj I/MotionEvent﹕ Action Down!
09-16 16:39:48.911 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.926 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.946 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.961 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.976 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:48.996 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.011 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.026 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.046 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.061 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.076 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.096 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.111 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.126 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.146 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.161 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.176 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.196 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.201 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
09-16 16:39:49.206 26748-26748/mobi.corp.proj I/MotionEvent﹕ Other Action!
当我只是期待一些
I/MotionEvent﹕ Action Down!
正在打印default
的日志,因为在屏幕上滑动时会调用ACTION_MOVE
并可能会调用ACTION_UP
。
如果要检测一个向下轻扫你需要得到y
上统筹ACTION_DOWN
和比较它y
统筹你得到ACTION_UP
。
如果ACTION_UP
的y
大于ACTION_UP
则向下滑动。
每次移动手指时都会调用MotionEvent.ACTION_MOVE
,这是一项连续的任务。 这将被称为它移动的每个像素。 因此您可能要从此类中排除MotionEvent.ACTION_MOVE
以减少噪音
您可以尝试使用本教程中介绍的方法来处理滑动。
例如:
// Private class for gestures
private class SwipeGestureDetector
extends SimpleOnGestureListener {
// Swipe properties, you can change it to make the swipe
// longer or shorter and speed
private static final int SWIPE_MIN_DISTANCE = 120;
private static final int SWIPE_MAX_OFF_PATH = 200;
private static final int SWIPE_THRESHOLD_VELOCITY = 200;
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2,
float velocityX, float velocityY) {
try {
float diffAbs = Math.abs(e1.getY() - e2.getY());
float diff = e1.getX() - e2.getX();
if (diffAbs > SWIPE_MAX_OFF_PATH)
return false;
// Left swipe
if (diff > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
YourActivity.this.onLeftSwipe();
// Right swipe
} else if (-diff > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
YourActivity.this.onRightSwipe();
}
} catch (Exception e) {
Log.e("YourActivity", "Error on gestures");
}
return false;
}
}
private void onLeftSwipe() {
// Do something
}
private void onRightSwipe() {
// Do something
}
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