UIButton addTarget:action:forControlEvents: results in [NSObject doesNotRecognizeSelector:]

Teodor picture Teodor · Jun 15, 2010 · Viewed 56.9k times · Source

I tried a lot of stuff, still no result.

So I have the following button created programatically in a subclass of UIViewController:

    rightButton = [UIButton buttonWithType:UIButtonTypeCustom];
    rightButton.frame = CGRectMake(0.0, 0.0, 110.0, 40.0);
    rightButton.titleLabel.font = [UIFont fontWithName:GAME_FONT_NAME_STRING size:20.0];
    [rightButton setTitle:@"MyTitle" forState:UIControlStateNormal];
    rightButton.backgroundColor = [UIColor clearColor];
    [rightButton setTitleColor:[UIColor greenColor] forState:UIControlStateNormal];
    [rightButton setTitleColor:[UIColor blackColor] forState:UIControlStateHighlighted];
    [rightButton setBackgroundImage:normalImage forState:UIControlStateNormal];
    [rightButton setBackgroundImage:highlightedImage forState:UIControlStateHighlighted];
    [rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:rightButton];

where the selector is:

- (void)myButton;

I tried everything:

- (void)myButton;
- (void)myButton:(id)sender;
- (void)myButton:(id)sender forEvent:(UIEvent *)event;
- (IBAction)myButton;
- (IBAction)myButton:(id)sender;
- (IBAction)myButton:(id)sender forEvent:(UIEvent *)event;

and the corresponding selectors, of course:

[rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton:) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton:forEvent:) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton:) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton:forEvent:) forControlEvents:UIControlEventTouchUpInside];

The result is always an uncaught exception - [NSObject doesNotRecognizeSelector:]. However, the usual backtrace of the program is:

#0  0x92a6bedb in objc_msgSend ()
#1  0x03b0a430 in ?? ()
#2  0x00306b4e in -[UIControl sendAction:to:forEvent:] ()
#3  0x00308d6f in -[UIControl(Internal) _sendActionsForEvents:withEvent:] ()
#4  0x00307abb in -[UIControl touchesEnded:withEvent:] ()
#5  0x002bcddf in -[UIWindow _sendTouchesForEvent:] ()
#6  0x002a67c8 in -[UIApplication sendEvent:] ()
#7  0x002ad061 in _UIApplicationHandleEvent ()
#8  0x02498d59 in PurpleEventCallback ()
#9  0x01cabb80 in CFRunLoopRunSpecific ()
#10 0x01caac48 in CFRunLoopRunInMode ()
#11 0x02497615 in GSEventRunModal ()
#12 0x024976da in GSEventRun ()
#13 0x002adfaf in UIApplicationMain ()

So what is the problem with that button?

PS: I am using the iPhone SDK 3.1.3


Update!

The following code in the AppDelegate (no declarations in the interface):

- (void)applicationDidFinishLaunching:(UIApplication *)application {
    UIButton *test = [[UIButton alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 100.0)];
    [test setTitle:@"Title" forState:UIControlStateNormal];
    UIImage *bg = [UIImage imageNamed:...];
    [test setBackgroundImage:bg forState:UIControlStateNormal];
    [test addTarget:self action:@selector(testAction) forControlEvents:UIControlEventTouchUpInside];
    [window addSubview:test];
    [test release];
    [window makeKeyAndVisible];
}

- (void)testAction {
    NSLog(@"Write something...");
}

works perfectly!

But if I create an empty UIViewController with the same code:

- (void)viewDidLoad {
    UIButton *test = [[UIButton alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 100.0)];
    [test setTitle:@"Title" forState:UIControlStateNormal];
    UIImage *bg = [UIImage imageNamed:...];
    [test setBackgroundImage:bg forState:UIControlStateNormal];
    [test addTarget:self action:@selector(testAction) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:test];
    [test release];
    [window makeKeyAndVisible];
}

- (void)testAction {
    NSLog(@"Write something...");
}

I get this mysterious error. :-( Help!

Answer

skajam66 picture skajam66 · Jan 1, 2011

An old post and probably all sorted by now but there is another problem that will cause a crash:

[test addTarget:self action:@selector(testAction) forControlEvents:UIControlEventTouchUpInside]

is incorrect. action:@selector(testAction) must have a colon there thus:

action:@selector(testAction:)

or else you'll get an unrecognised selector crash - which is what you are getting..