accessing UIButton by (id)sender

Question

I have the following code

-(IBAction)ATapped:(id)sender{
//want some way to hide the button which is tapped
self.hidden = YES;
}

Which is linked to multiple buttons. I want to hide the button which triggered this IBAction. self.hidden is obviously not the button.

How do I hide the button which was tapped? The sender.

Thanks

score 13 · Answer 1 · answered Nov 06 '10 at 13:37

Both Vladimir and Henrik's answers would be correct. Don't let the 'id' type scare you. It's still your button object it's just that the compiler doesn't know what the type is. As such you can't reference properties on it unless it is cast to a specific type (Henrik's answer).

-(IBAction)ATapped:(id)sender{
   // Possible Cast
   UIButton* myButton = (UIButton*)sender;
   myButton.hidden = YES;
}

Or you can send any message (call any method) on the object, assuming YOU know the type (which you do, it's a button), without having to cast (Vladimir's answer).

-(IBAction)ATapped:(id)sender{
   //want some way to hide the button which is tapped
   [sender setHidden:YES];
}

Both methods can throw an error: my Method could throw a Casting Error and Vladimirs Method could throw a messaging error — Henrik P. Hessel, Nov 06 '10 at 13:41

score 8 · Accepted Answer · answered Nov 06 '10 at 13:31

8

Send setHidden message to sender:

-(IBAction)ATapped:(id)sender{
   //want some way to hide the button which is tapped
   [sender setHidden:YES];
}

answered Nov 06 '10 at 13:31

Vladimir

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I tried sender.hidden = YES; before I posted this. it gave an error. – some_id Nov 06 '10 at 13:46
Ok, .hidden gives a "not a structure or union" error, but[ setHidden:YES] works ;) – some_id Nov 06 '10 at 13:52
To user property .hidden you must case sender to UIButton - like in Henrik answer, and setHidden message you can send to any object. However if you're not 100% sure that sender is UIButton then you should perform a check if sender responds to setHidden – Vladimir Nov 06 '10 at 13:59
Or a check to see if it was a button. (`if ([sender isMemberOfClass:[UIButton class]]){ [sender setHidden:YES]; }`) – Emil Nov 06 '10 at 16:39
1

@Emil, better use isKindOfClass: then - to handle also UIButton subclass cases. Even better to use respondsToSelector: method for check – Vladimir Nov 06 '10 at 16:56

score 2 · Answer 3 · answered Nov 06 '10 at 13:31

2

Your getting the button object (id) provided as a parameter

-(IBAction)ATapped:(id)sender{
   // Possible Cast
   UIButton* myButton = (UIButton*)sender;
   myButton.hidden = YES;
}

answered Nov 06 '10 at 13:31

Henrik P. Hessel

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score 2 · Answer 4 · edited Jul 04 '14 at 13:38

2

If you want bullet proof cast/messaging, try this:

-(IBAction)ATapped:(id)sender{
   // Secure Cast of sender to UIButton
   if ([sender isKindOfClass:[UIButton class]]) {
       UIButton* myButton = (UIButton*)sender;
       myButton.hidden = YES;
   }
}

edited Jul 04 '14 at 13:38

Florian

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answered Nov 06 '10 at 16:21

Erdemus

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I believe NSButton should be UIButton, but yes, thanks for this. – Thunder Rabbit Jul 03 '12 at 22:43

score 0 · Answer 5 · edited Apr 19 '15 at 09:39

0

And... if you want to change the backgroundcolor of a button, the correct code will be like this?

[sender setBackgroundColor:(NSColor *)redColor];

for example? ... because it is´nt works for my...

edited Apr 19 '15 at 09:39

MD SHAHIDUL ISLAM

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answered Dec 18 '10 at 15:47

AlextaNET

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accessing UIButton by (id)sender

5 Answers5