ios – 触摸时没有调用的UIButton触摸操作,但触摸移动时调用

[button addTarget:self action:@SELEctor(touchDown:event:) forControlEvents:UIControlEventTouchDown];
[button addTarget:self action:@SELEctor(drag:event:) forControlEvents:UIControlEventTouchDragInside];
[button addTarget:self action:@SELEctor(drag:event:) forControlEvents:UIControlEventTouchDragOutside];
[button addTarget:self action:@SELEctor(touchUp:event:) forControlEvents:UIControlEventTouchUpInside];
[button addTarget:self action:@SELEctor(touchUp:event:) forControlEvents:UIControlEventTouchUpOutside];

- (void)touchDown:(UIButton *)sender event:(UIEvent *)event {
    //begin only called when I move my finger 
}


- (void)drag:(UIButton *)sender event:(UIEvent *)event {
    //called when I move my finger,after touchDown was called
}
- (void)touchUp:(UIButton *)sender event:(UIEvent *)event {

}

我的应用程序的根视图控制器是tabbarviewcontroller,每个选项卡都是导航视图控制器.在聊天场景的viewWillAppear方法中,我隐藏了标签栏.

结果是,在设备上,当我触摸时,它没有被调用,当我移动我的手指时,它被调用.

注意：

>使用长按手势识别器也不起作用.
>如果我将按钮远离标签栏区域,它可以在设备上运行.
>在模拟器上,一切都很好.

我创建了一个示例项目：
https://drive.google.com/folderview?id=0B_9_90avvmZtRmRDeHFkbFJLaFk&usp=sharing