Question

i’m new to obj-c and i’m trying to code a simple IBAction where a button once clicked change its label. it works good with image background and static string, but when it crashes on this:

int i = (arc4random()%90);
NSString *lab = [NSString stringWithFormat:@"%d", i];
[sender setText:lab];

why? ty in advance

edit: this is the whole method

-(IBAction) toggleUIButtonImage:(id)sender{
    NSString *img = @"bulldog-cute-tom-bancroft.jpg";
    NSString *imgSel = @"kitten-cute-tom-bancroft.jpg";
    UIImage *unselectedImage = [UIImage imageNamed:img];
    UIImage *selectedImage = [UIImage imageNamed:imgSel];
    if ([sender isSelected]) {
        [sender setBackgroundImage:unselectedImage forState:UIControlStateNormal];
        [sender setSelected:NO];
    }else {
        [sender setBackgroundImage:selectedImage forState:UIControlStateSelected];
        [sender setSelected:YES];
    }

    int i = (arc4random()%90);
    NSString *lab = [NSString stringWithFormat:@"%d", i];
    [sender setTitle:lab forState: UIControlStateNormal];

} 

Answer 1

It’s not the random int or the int2str conversion. It’s the way you set the text of your button.
Use this and it should work:

[sender setTitle: lab forState: UIControlStateNormal]; 

(That is if sender actually is a UIButton of course)

EDIT:

UIButton *button = (UIButton *)sender; 

A cast from sender to UIButton* (or any other specific class you want to make respond to the method) is recommended for this as well to ensure you work with the right classmethods.