Can't programmatically hide UIButton created w

Question

My iOS UIButton is correctly linked from IB to an IBOutlet in my view controller, as I can change its title from my code. Ie:

[self.myButton setTitle:@"new title" forState:UIControlStateNormal]; //works

However,

[self.myButton setHidden:YES]; //doesn't work
//or
self.myButton.hidden = YES; //doesn't work

What's going on? How can I make myButton disappear?

Update: some additional info

Here's the code related in to my UIButton:

in my .h file

IBOutlet UIButton *myButton;
-(IBAction)pushedMyButton:(id)sender;
@property (nonatomic,retain) UIButton *myButton;

in my .m file

@synthesize myButton;
- (void)pushedMyButton:(id)sender{
    self.myButton.hidden = YES;
}
- (void)dealloc{
    [self.myButton release];
}

Answer 1

What worked for me is putting the manipulating code in viewDidLoad instead of initWithNibName, like this:

- (void)viewDidLoad
{
    btnRestart.enabled = false;
}

Answer 2

That should work, try rename it and hide it just to check that there aren't two buttons on top of each other.

Answer 3

I had this same problem and found the solution was to put the hidden in the right place, in my case in the viewDidLoad function.

Answer 4

Ok I found a workaround that works but I still don't know why my original code wasn't working in the first place. I used Grand Central Dispatch to dispatch a block containing the hide call on the main queue, like this:

dispatch_async(dispatch_get_main_queue(), ^{
    self.myButton.hidden = YES; //works
});

Interesting. None of the initial code in my IBOutlet was wrapped in GCD blocks though. Any ideas?

Answer 5

User Interface (UI) API (UIKit ...) methods have to be run on Main Thread!

So this will run on Main thread (as *dispatch_get_main_queue*):

dispatch_async(dispatch_get_main_queue(), ^{
    self.myButton.hidden = YES; //works
});

BUT usually we do something like this:

[self performSelectorOnMainThread:@selector(showButton) withObject:nil waitUntilDone:NO];

[self performSelectorOnMainThread:@selector(hideButton) withObject:nil waitUntilDone:NO];

-(void)showButton
{
    myButton.hidden = NO;
}

-(void)hideButton
{
    myButton.hidden = YES;
}

As per Apple's documentation: http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html " Threading Considerations Manipulations to your application’s user interface must occur on the main thread. Thus, you should always call the methods of the UIView class from code running in the main thread of your application. The only time this may not be strictly necessary is when creating the view object itself but all other manipulations should occur on the main thread. "