How to convert "SEL" and "id" to NSString?

Question

id parent;
SEL selector;

// lot's of code...

if ([parent respondsToSelector:selector]) {

}
else {
    // This doesn't work:
    NSString *errorMessage = [NSString stringWithFormat:@"%@ in class %@ doesn't exist!", selector, parent];
}

How do I convert "SEL" and "id" to a String?

Solution

Call NSStringFromSelector() passing your selector as its argument to get the selector string, and use [parent class] for the parent object's class:

NSString *errorMessage = [NSString stringWithFormat:@"%@ in class %@ doesn't exist!",
    NSStringFromSelector(selector), 
    [parent class]];

Comments

[Takagi]

The opposite way is: SEL aSelector = NSSelectorFromString(@"tapMeAction:");

[owen gerig]

just wanted to point out that "@%s",_cmd use to work (and still does) but now post a warning. this seems to be the proper way

[Benji XVI]

Note - the format of the string returned by NSStringFromSelector is simply the selector, e.g. @"setTitle:". i.e. it has no @selector(~) wrapping etc.