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[Objective-C] Passing parameters to addTarget:action:forControlEvents

Answer 1

A:

See my comment above, and I believe you have to use NSInvocation when there is more than one parameter

more information on NSInvocation here

http://cocoawithlove.com/2008/03/construct-nsinvocation-for-any-message.html

Aaron Saunders 2010-10-21 14:27:41

Actually, I don't want to pass several params, I just want an integer.

Nonepse 2010-10-21 14:33:39

actually there's performSelector:withObject:withObject: method that allow to call selectors with 2 parameters. But for more you need NSInvocation

Vladimir 2010-10-21 14:35:08

@Vladimir thanks, did not know that

Aaron Saunders 2010-10-21 14:39:32

Answer 2

+1 A:

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:

with no parameters
```
action:@selector(switchToNewsDetails)
```
with 1 parameter indicating the control that sends the message
```
action:@selector(switchToNewsDetails:)
```
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:

set a tag property to each button equal to required index

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
}

Vladimir 2010-10-21 14:33:23

Thanks, this tip will allow me to get an "id" in switchToNewsDetails :)

Nonepse 2010-10-21 14:42:39

Answer 3

+1 A:

Target-Action allows three different forms of action selector:

- (void)action
- (void)action:(id)sender
- (void)action:(id)sender forEvent:(UIEvent *)event

Benoît 2010-10-21 14:33:45

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[Objective-C] Passing parameters to addTarget:action:forControlEvents

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