Question

I’m writing a custom helper method that will get used a lot and return several buttons. Each button will of course have its own target selector when pressed, and I want to pass the selector as a parameter into this method so the returned button has the specified selector.

But I’m not sure how to pass a selector as a method parameter. Something like this:

-(returnedInstance)someMethod:(WhatClass?*)selectedFunction{

[SomeClassWithASelectorParameter method:whatever selector:@selector(selectedFunction)];

}

where selectedFunction is a parameter passed into the method.

I tried making WhatClass?* a NSString and also SEL but that resulted in:

[NSInvocation invocationWithMethodSignature:]: method signature argument cannot be nil

Answer 1

Why don’t you just pass a SEL? i.e. a selector. Like so:

-(returnedInstance)someMethod:(SEL)selectedFunction{
    [SomeClassWithASelectorParameter method:whatever selector:selectedFunction];
}

Alternatively, NSSelectorFromString:

-(returnedInstance)someMethod:(NSString*)selectedFunction{
    [SomeClassWithASelectorParameter method:whatever selector:NSSelectorFromString(selectedFunction)];
}