Question

So let’s say I have this method that responds to a button event

- (void) myMethod: (id) sender

Is it better to use directly the function param?

NSLog(@"The sender tag is %d",sender.tag);

Or is it better to create a new object?

UIButton* myButton = (UIButton*) sender;
NSLog(@"The sender tag is %d",myButton.tag);

Why?

I’ve seen in tutorials that the preferred way in objective-c is the second one. But, in cases where you don’t need to know the type of the sender and just access its properties/methods it should be Ok to use the first way. Am I missing something?

Answer 1

You’re not missing anything and this isn’t a particularly important issue. You have a few options:

NSLog(@"%d", sender.tag);

Sometimes that will produce warnings when compiling, depending on the type of the method parameter.

NSLog(@"%d", ((UIButton *)sender).tag);

Or finally:

UIButton *button = (UIButton *)sender;
NSLog(@"%d", button.tag);

(These all basically do the same thing, so it’s mostly a matter of preference.)