Question

I have the following code which takes a touch on one button and draws a border around that button, then makes sure that all the other buttons have no border (8 buttons total). This is a method in a singleton class called AnswerButtons. This code works fine.

- (IBAction)button1WasTouched:(id)sender {

    NSLog(@"Hello from button 1");

    // retrieve, modify and update clueAnsState

    NSMutableArray *newCAS = [[GameData gameData].curData objectForKey:@"clueAnsState"];
   [newCAS replaceObjectAtIndex:0
                     withObject:@"2"];
    [[GameData gameData].curData setObject:newCAS
                                    forKey:@"clueAnsState"];

    // Highlight the pressed button & make sure other buttons are not highlighted

    for (NSInteger idx = 0; idx < 8; idx++) {
        NSString *temp = [newCAS objectAtIndex:idx];
        if ([temp isEqualToString:@"1"]) {
            UIButton *b = [[AnswerButtons answerButtons].buttons objectAtIndex:idx];
            [[b layer] setBorderWidth:0.0f];
        }
        if ([temp isEqualToString:@"2"]) {
            UIButton *b = [[AnswerButtons answerButtons].buttons objectAtIndex:idx];
            [[b layer] setBorderWidth:2.0f];
        }
    }

}

Now, I need to use this code for all 8 buttons, so I should write a method with one argument, the button number to modify (pos). In the singleton class .m I put which is virtually the same code:

    - (void)activateAnswerAtPos:(int)pos {

    // retrieve, modify and update clueAnsState

    NSMutableArray *newCAS = [[GameData gameData].curData objectForKey:@"clueAnsState"];
    [newCAS replaceObjectAtIndex:pos
                      withObject:@"2"];
    [[GameData gameData].curData setObject:newCAS
                                    forKey:@"clueAnsState"];

    NSLog(@"%@", newCAS);

    for (NSInteger idx = 0; idx < 8; idx++) {
        NSString *temp = [newCAS objectAtIndex:idx];
        if ([temp isEqualToString:@"1"]) {
            UIButton *b = [[AnswerButtons answerButtons].buttons objectAtIndex:idx];
            [[b layer] setBorderWidth:0.0f];
       }
       if ([temp isEqualToString:@"2"]) {
            UIButton *b = [[AnswerButtons answerButtons].buttons objectAtIndex:idx];
            [[b layer] setBorderWidth:2.0f];
        }
    }
}

So I changed the first code chunk to make it a call to the new method:

- (IBAction)button1WasTouched:(id)sender {

    NSLog(@"Hello from button 1");
    [sender activateAnswerAtPos:0];
}

Unfortunately, I’m doing something wrong as I get the following exception:

2012-03-30 19:41:40.199 P3[6751:f803] Hello from button 1
2012-03-30 19:41:40.201 P3[6751:f803] -[UIRoundedRectButton activateAnswerAtPos:]: unrecognized selector sent to instance 0x6e709f0

I’m not sure what’s going on here; several alternatives don’t work either and I think my troubleshooting is sending me in the wrong direction. What’s wrong with the way I am calling this method? Clearly I’m not even getting to run the method. TIA.

Answer 1

You’re calling -activateAnswerAtPos: on sender, which is the button that was touched. You should instead call it on the instance of the class that defines the -activateAnswerAtPos: method. It’s not clear from your code what that is, but my guess is self:

[self activateAnswerAtPos:0];