UIButton subclass highlighting error (highlight remains or persists even after tap or touch down)

Question

I subclassed UIButton in my app and there are many times when the highlight color stays even when I'm done pressing down the button. I can't figure out exactly what causes this since it only seems to happen by chance, but it seems to happen about 50% of the time. I'm very sure that this is reproducible. I often get this to happen when I have a button in a UITableViewCell and I click on it while the table view is still scrolling.

Is there something wrong with the way I'm overriding the setHighlighted method in the subclass? This is my implementation:

@implementation SCPFormButton

- (id)initWithFrame:(CGRect)frame label:(NSString *)label
{
    self = [super initWithFrame:frame];
    if (self) {
        UILabel *buttonLabel = [[UILabel alloc] init];
        buttonLabel.attributedText = [[NSAttributedString alloc] initWithString:[label uppercaseString] attributes:kButtonLabelAttributes];
        [buttonLabel sizeToFit];
        buttonLabel.frame = CGRectMake(kMaxWidth / 2 - buttonLabel.frame.size.width / 2, kStandardComponentHeight / 2 - buttonLabel.frame.size.height / 2, buttonLabel.frame.size.width, buttonLabel.frame.size.height);
        [self addSubview:buttonLabel];

        self.backgroundColor = kFormButtonColorDefault;
    }
    return self;
}

- (void)setHighlighted:(BOOL)highlighted
{
    self.backgroundColor = highlighted ? kFormButtonColorHighlighted : kFormButtonColorDefault;
    [self setNeedsDisplay];
}

@end

Answer 1

I would try to call super in your setHighlighted override. Indeed, Apple docs for UIControl state:

Specify YES if the control is highlighted; otherwise NO. By default, a control is not highlighted. UIControl automatically sets and clears this state automatically when a touch enters and exits during tracking and when there is a touch up.

So, it seems there is some kind of state handling going on in UIControl associated with this.

If this does not help, I would try to add a log trace so you can check which state the button is in when the touch is handled.

Answer 2

You are missing the call to super. But, anyway, subclassing UIButton is not recommended, I would try to do it using setBackgroundImage:forState instead.