Objective-C: Calling selectors with multiple arguments

Question

In MyClass.m, I've defined

- (void) myTest: (NSString *) withAString{
    NSLog(@"hi, %@", withAString);
}

and the appropriate declaration in MyClass.h . Later I want to call

[self performSelector:@selector(mytest:withAString:) withObject: mystring];

in MyClass.m but I get an error similar to * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[MyClass myTest:withAtring:]: unrecognized selector sent to instance 0xe421f0'

I tried a simpler case with a selector that took no arguments that printed a string to console and that worked just fine. What's wrong with the code and how can I fix it? Thanks.

Answer 1

Your method signature is:

- (void) myTest:(NSString *)

withAString happens to be the parameter (the name is misleading, it looks like it is part of the selector's signature).

If you call the function in this manner:

[self performSelector:@selector(myTest:) withObject:myString];

It will work.

But, as the other posters have suggested, you may want to rename the method:

- (void)myTestWithAString:(NSString*)aString;

And call:

[self performSelector:@selector(myTestWithAString:) withObject:myString];