If the stepper were triggered by a gesture recognizer, wouldn't I expect to see the gesture recognizer in the call tree?
The stack trace reveals that the stepper's _updateCount
method is dispatched through a timer.
This could be related to the fact that a stepper has an "autoIncrement" mode where, as long as your keep it pressed, it will update at a given (varying) rate. So, instead of simply calling _updateCount
, the stepper sets up a timer to handle this behaviour.
For whatever reason the timer is used, the timer explains why you do not see the gesture recogniser in the stack trace.
In your case what happens is that the stepper gets the touches, handles them, and do not forward them to any gesture recognisers attached to it.
This can be explained as follows, although this snippet does not explicitly mention a long press recogniser in relation to a UIStepper
control:
According to Apple Docs:
Interacting with Other User Interface Controls
In iOS 6.0 and later, default control actions prevent overlapping gesture recognizer behavior. For example, the default action for a button is a single tap. If you have a single tap gesture recognizer attached to a button’s parent view, and the user taps the button, then the button’s action method receives the touch event instead of the gesture recognizer. This applies only to gesture recognition that overlaps the default action for a control, which includes:
A single finger single tap on a UIButton, UISwitch, UIStepper, UISegmentedControl, and UIPageControl.
...
If you have a custom subclass of one of these controls and you want to change the default action, attach a gesture recognizer directly to the control instead of to the parent view. Then, the gesture recognizer receives the touch event first. As always, be sure to read the iOS Human Interface Guidelines to ensure that your app offers an intuitive user experience, especially when overriding the default behavior of a standard control.
So, it seems you can attach the gesture recogniser directly to the control (possibly you need to subclass UIStepper
for this to work, I am not really sure how to interpret the last paragraph). Hopefully this will not disable the basic workings of the stepper (but maybe it will).