Get all instances of a class in objective c?

Question

I have a UIView that has many instances and each one of them has a UIRecognizer.

When on of them is tapped I want to remove all the recognizers of the others.

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Answer 1

If they're all subviews of the same view, you could iterate over parentView.subviews and find them that way. Something like this:

for (UIView *v in parentView.subviews) {
    if ([v isKindOfClass:[MyViewClass class]]) {
        // remove recognizer here
    }
}

Another, more efficient, option would be to have a flag in your view controller that you set when the first recognizer is triggered and use to short-circuit any future recognizer handler calls. Something like this:

@property (nonatomic) BOOL shouldRespondToEvent;
@synthesize shouldRespondToEvent=_shouldRespondToEvent;

- (void)viewDidLoad {
    [super viewDidLoad];
    self.shouldRespondToEvent = YES;
    // other viewDidLoad stuff here
}

- (void)gestureHandler:(UIGestureRecognizer*)recognizer {
    if (!self.shouldRespondToEvent)
        return;
    self.shouldRespondToEvent = NO;
    // rest of handler code here
}