iPhone UIBarButtonItem setEnabled in NSThread - iphone

Question

I'm trying to change the enabled property of an UIBarButtonItem after doing some stuff in an NSThread. After pressing the button I set the enabled to NO then perform the threaded part and at the end I try to re enable the button. Fairly basic.
Somehow this fails, however I'm able to change any other property of the the UIBarButtonItem correctly (for ex. title).
What am I doing wrong here?
#interface myViewController : UIViewController <UITableViewDataSource, UITableViewDelegate> {
IBOutlet UIBarButtonItem *myButton;
}
#property (nonatomic, retain) IBOutlet UIBarButtonItem *myButton;
- (IBAction)mysub:(id)sender;
#end
#implementation myViewController
#synthesize myButton;
- (IBAction)mysub:(id)sender {
[myButton setEnabled:NO];
[NSThread detachNewThreadSelector:#selector(mysub_threaded) toTarget:self withObject:nil];
}
- (void) mysub_threaded {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
… do threaded stuff
[myButton performSelectorInBackground: # selector(setEnabled :) withObject: [NSNumber numberWithBool:YES]];
[pool drain];
}

Answer 1

You want performSelectorOnMainThread instead.
[myButton performSelectorOnMainThread:#selector(setEnabled:)
withObject:[NSNumber numberWithBool:YES]
waitUntilDone:NO];
Always do anything that touches the UI on the main thread.
But sometimes passing arguments like this is funky too. I find it best to wrap up everything you need done in another method
- (void)mysub_complete {
[myButton setEnabled:YES];
}
Then call that with
[self performSelectorOnMainThread:#selector(mysub_complete)
withObject:nil
waitUntilDone:NO];
Now you can do as much other UI stuff as you want without worry about it.