Passing arguments to selector

Question

hi, i have been working on a small demo and i wrote a function which accepts two string object and looks like this

-(void)adding:(NSString*)num1 :(NSString*)num2
{
    num1 = first.text; //first is object of label
    num2 = second.text; //second is object of label

    int x= [num1 integerValue];
    int y = [num2 integerValue];

    int r = x+y;
    NSLog(@"%d",r);
}

am having one more function

-(void)calling
{
    [self performSelector:@selector(adding:)withObject:@"num1" withObject:@"num2"];
}

and am calling the method named calling on button touch up inside event

[btn addTarget:self action:@selector(calling) forControlEvents:UIControlEventTouchUpInside];

but i get an error called unrecognized selector sent to instance

can you please tell me where i am wrong and how to pass methods with arguments to selector. Thank you

Answer 1

You're missing a colon. Try this :

[self performSelector:@selector(adding::)withObject:@"num1" withObject:@"num2"];

However, it's bad form to have unnamed parameters on your method names because errors like this happen ;)

I'd rename your method to be

-(void)adding:(NSString*)num1 to:(NSString*)num

and have this line :

[self performSelector:@selector(adding:to:)withObject:@"num1" withObject:@"num2"];

Answer 2

You got your selector wrong, it should be @selector(adding::)

Also in this case you don’t need to use performSelector:..., you can send the message directly: [self adding: @"num1" : @"num2"].