Passing parameters to addTarget:action:forControlEvents

Pierre Espenan picture Pierre Espenan · Oct 21, 2010 · Viewed 118.4k times · Source

I am using addTarget:action:forControlEvents like this:

[newsButton addTarget:self
action:@selector(switchToNewsDetails)
forControlEvents:UIControlEventTouchUpInside];

Answer

Vladimir picture Vladimir · Oct 21, 2010
action:@selector(switchToNewsDetails:)

You do not pass parameters to switchToNewsDetails: method here. You just create a selector to make button able to call it when certain action occurs (touch up in your case). Controls can use 3 types of selectors to respond to actions, all of them have predefined meaning of their parameters:

  1. with no parameters

    action:@selector(switchToNewsDetails)
    
  2. with 1 parameter indicating the control that sends the message

    action:@selector(switchToNewsDetails:)
    
  3. With 2 parameters indicating the control that sends the message and the event that triggered the message:

    action:@selector(switchToNewsDetails:event:)
    

It is not clear what exactly you try to do, but considering you want to assign a specific details index to each button you can do the following:

  1. set a tag property to each button equal to required index
  2. in switchToNewsDetails: method you can obtain that index and open appropriate deatails:

    - (void)switchToNewsDetails:(UIButton*)sender{
        [self openDetails:sender.tag];
        // Or place opening logic right here
    }