如何将观察者添加到UIButton？

Question

I want be signaled when user will touch button (UIControlEventTouchUpInside). How do I add observer to UIButton?

Answer 1

Look at the documentation of UIControl .

[myButton addTarget:self 
             action:@selector(touch:) 
   forControlEvents:UIControlEventTouchUpInside];

This method works for anything that inherits from UIControl (including but not limited to UIButtons :)

Answer 2

// add target and action
[myButton addTarget:self 
             action:@selector(buttonClicked:) 
   forControlEvents:UIControlEventTouchUpInside];

where the target is the class where the UIButton is added or implemented. If you set nil for addTarget, the action will go through the responder chain until a responder is found that responds to the buttonClicked: selector. buttonClicked: selector is implemented like the following:

-(void)buttonClicked:(id)sender
{
 // do stuff here
}