Objective-c: NSButton setAction not working

Question

I'm making a couple of buttons programmatically and trying to set an action to each but I can't seem to get it to work.

In my AppController.h I have this code:

...
IBOutlet NSButton* btnZoomIn;
IBOutlet NSButton* btnZoomOut;
...

and

- (IBAction) zoomIn : (id) sender; 

- (IBAction) zoomOut : (id) sender;

and in AppController.m within the awakeFromNib method:

/*zoom in and out buttons*/

//get the path to the image files
NSString* zoomInImgPath = [[NSBundle mainBundle] pathForResource:@"zoomIn" ofType:@"png"];
NSString* zoomOutImgPath = [[NSBundle mainBundle] pathForResource:@"zoomOut" ofType:@"png"];

//declare the NSImages
zoomInImg = [[NSImage alloc] initWithContentsOfFile:zoomInImgPath];
zoomOutImg = [[NSImage alloc] initWithContentsOfFile: zoomOutImgPath];

//button making!
//zoomIn
btnZoomIn = [[NSButton alloc] initWithFrame:NSMakeRect(1426.0, 920.0, 25.0, 25.0)];
[btnZoomIn setButtonType:NSMomentaryPushInButton];
[btnZoomIn setTitle:@""];
[btnZoomIn setToolTip:@"Zoom In"];
[btnZoomIn setImage:zoomInImg];
[btnZoomIn setAction:@selector(zoomIn:)];
[[mainWin contentView] addSubview:btnZoomIn];

//zoomOut
btnZoomOut = [[NSButton alloc] initWithFrame:NSMakeRect(1456.0, 920.0, 25.0, 25.0)];
[btnZoomOut setButtonType:NSMomentaryPushInButton];
[btnZoomOut setTitle:@""];
[btnZoomOut setToolTip:@"Zoom Out"];
[btnZoomOut setImage:zoomOutImg];
[btnZoomOut setAction:@selector(zoomOut:)];
[[mainWin contentView] addSubview:btnZoomOut];

and

- (IBAction) zoomIn : (id) sender  { 
    NSLog(@"zoom in!");
 }

 - (IBAction) zoomOut : (id) sender { 
    NSLog(@"zoom out!");
 }

but zoomOut and zoomIn do not get hit...

Answer 1

The most likely reason is that there’s no object in the responder chain for action messages responding to those actions. When you specify an action but don’t specify a target, Cocoa tries to find an object that responds to those action messages by traversing the responder chain.

Either make sure that you have a suitable object in the responder chain or, if you have a reference to that object, specify it as the target of those actions:

[btnZoomIn setAction:@selector(zoomIn:)];
[btnZoomIn setTarget:objectThatRespondsToZoomIn];

[btnZoomOut setAction:@selector(zoomOut:)];
[btnZoomOut setTarget:objectThatRespondsToZoomOut];