这个想法是创建一个Runnable 以在将来执行长点击,但是这个执行可以因为点击或移动而被取消。
您还需要知道,什么时候消耗了长按,什么时候因为手指移动太多而取消。我们使用initialTouchX & initialTouchY 来检查用户是否退出了一个 10 像素的正方形区域,每边 5 个。
这是我将 Click & LongClick 从ListView 中的Cell 委托给Activity 和OnTouchListener 的完整代码:
ClickDelegate delegate;
boolean goneFlag = false;
float initialTouchX;
float initialTouchY;
final Handler handler = new Handler();
Runnable mLongPressed = new Runnable() {
public void run() {
Log.i("TOUCH_EVENT", "Long press!");
if (delegate != null) {
goneFlag = delegate.onItemLongClick(index);
} else {
goneFlag = true;
}
}
};
@OnTouch({R.id.layout})
public boolean onTouch (View view, MotionEvent motionEvent) {
switch (motionEvent.getAction()) {
case MotionEvent.ACTION_DOWN:
handler.postDelayed(mLongPressed, ViewConfiguration.getLongPressTimeout());
initialTouchX = motionEvent.getRawX();
initialTouchY = motionEvent.getRawY();
return true;
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_CANCEL:
if (Math.abs(motionEvent.getRawX() - initialTouchX) > 5 || Math.abs(motionEvent.getRawY() - initialTouchY) > 5) {
handler.removeCallbacks(mLongPressed);
return true;
}
return false;
case MotionEvent.ACTION_UP:
handler.removeCallbacks(mLongPressed);
if (goneFlag || Math.abs(motionEvent.getRawX() - initialTouchX) > 5 || Math.abs(motionEvent.getRawY() - initialTouchY) > 5) {
goneFlag = false;
return true;
}
break;
}
Log.i("TOUCH_EVENT", "Short press!");
if (delegate != null) {
if (delegate.onItemClick(index)) {
return false;
}
}
return false;
}
ClickDelegate是一个interface,用于像Activity一样将点击事件发送到处理程序类
public interface ClickDelegate {
boolean onItemClick(int position);
boolean onItemLongClick(int position);
}
如果您需要委托行为,您只需在您的 Activity 或父 View 中实现它:
public class MyActivity extends Activity implements ClickDelegate {
//code...
//in some place of you code like onCreate,
//you need to set the delegate like this:
SomeArrayAdapter.delegate = this;
//or:
SomeViewHolder.delegate = this;
//or:
SomeCustomView.delegate = this;
@Override
public boolean onItemClick(int position) {
Object obj = list.get(position);
if (obj) {
return true; //if you handle click
} else {
return false; //if not, it could be another event
}
}
@Override
public boolean onItemLongClick(int position) {
Object obj = list.get(position);
if (obj) {
return true; //if you handle long click
} else {
return false; //if not, it's a click
}
}
}