Button #selector not working if button defined in NSObject - ios

Question

I have the following problem: I am trying to define a button in an NSObject (in a separate file) and add it to my ViewController:
NSObject method:
in obj.h:
+(void)NewButtonInView:(UIView *)view withAction:(SEL)actionbutton;
in obj.m
+(void)NewButtonInView:(UIView *)view withAction:(SEL)actionbutton {
UIButton *button = [[UIButton alloc] init];
button.frame = CGRectMake(0, 0, 50, 50);
[button addTarget:self action:actionbutton forControlEvents:UIControlEventTouchUpInside];
}
in my ViewCotroller I import the obj.h and:
[obj NewButtonInView:[self view] withAction:#selector(actionB:)];
and:
-(void)actionB:(UIButton *)button {
//some code
}
The button looks fine but when I click it I get the following error:
"[obj actionB:]: unrecognized selector sent to class"
Any help is appreciated.
Thank you.

Answer 1

the problem is this line
[button addTarget:self action:actionbutton forControlEvents:UIControlEventTouchUpInside];
specifically, the use of self. You put the actionB: method in the viewController, but because the NewButtonInView:withAction: method is in a class method of obj self refers to the class obj. To fix it pass in the view controller as a parameter to the method like this
+(void)NewButtonInView:(UIView *)view withAction:(SEL)actionbutton target: (id) target {
UIButton *button = [[UIButton alloc] init];
button.frame = CGRectMake(0, 0, 50, 50);
[button addTarget: target action:actionbutton forControlEvents:UIControlEventTouchUpInside];
}

Answer 2

Try defining it with a return value, as follows:
+(UIButton *)NewButtonInView:(UIView *)view withAction:(SEL)actionbutton withTarget:(id)target{
UIButton *button = [[UIButton alloc] init];
button.frame = CGRectMake(0, 0, 50, 50);
[button addTarget:target action:actionbutton forControlEvents:UIControlEventTouchUpInside];
return button;
}
Then when you call it:
UIButton *button = [obj NewButtonInView:[self view] withAction:#selector(actionB:) withTarget:self];
Not sure why you're doing it in an NSObject instead of in your view controller, but that's the way to go about it if you do.