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Editorial Team
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Asked: 2026-06-05T06:40:48+00:00

Given one example here, ( with ARC ) UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self

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Given one example here, ( with ARC ) 

        UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(onTap:)];

        [subView1 addGestureRecognizer:tapGesture ];
        [subView2 addGestureRecognizer:tapGesture];

Here is the problem:

subView1 will not response to the tapGesture , but subView2 will.

subView1 will work if we remove tapGesture from subview2.

What happens inside in terms of memory management ? Why not design to make above code work ?

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1 Answer

  1. Editorial Team

    Im quite sure that the standard gesture recognizers included in iOS can only be attached to one view at a time. I can’t find anything that states it explicitly but if you look at the UIGestureRecognizer class there is a view property with this description:

    The view the gesture recognizer is attached to. (read-only)

    So my guess is that addGestureRecgnizer: will unattach the reconizer if it’s already attached to a view.

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