Question

I have a method as an NSString *. If it exists, I want to call it, and if not, do nothing.

SEL eventSelector = NSSelectorFromString(eventSelectorStr);
if ([delegate respondsToSelector:eventSelector]) {
    [delegate performSelector:eventSelector];
    [delegate adapterDidFinishAdRequest:self];
}
else {
    // Does not implement selector
}

This code does not work, since NSSelectorFromString will register the string as a selector, so respondsToSelector:eventSelector will cause a crash because the selector is actually invalid.

Answer 1

Why do you say that that doesn’t work? This is the most common way to implement invoking optional delegate methods. I’ve never had an issue with that construct not working.