ios - How to debug who is eating my touches in UIKit?

Question

I can't figure out why tapping on text fields and buttons in my view is not working. I've checked all the obvious things like whether userInteractionEnabled is set to YES, whether a gesture recognizer is installed, and if there is an invisible view in the foreground.

Is there a best practice in iOS for tracing a touch from when it first appears to where it gets consumed?

UPDATE:

Both answers were helpful. During the course of my investigation I learned that if a subview is outside of its parent's bounds, even if the parent is not clipping subviews, the subview will not receive events. I printed out the chain of superviews from the text field that was not getting touches, and I saw that one of those views had a height of 0. I put in some constraints to stretch it out, and my problem was solved.

question from:https://stackoverflow.com/questions/26109023/how-to-debug-who-is-eating-my-touches-in-uikit

Answer 1

You can debug that by using a symbolic breakpoint:

-[UIWindow sendEvent:] & po $arg3

Logs:

<UITouchesEvent: 0x6000026fa6d0> timestamp: 179462 touches: {(
<UITouch: 0x7f84d6f10380> phase: Began tap count: 1 force: 0.000 
window: <UIWindow: 0x7f84d6d0ad10; frame = (0 0; 375 812); autoresize = W+H; 
gestureRecognizers = <NSArray: 0x600001aa8870>; layer = <UIWindowLayer: 0x6000014bd7e0>> view: <UIView: 0x7f84d6d0bff0; frame = (0 0; 375 812); 
autoresize = W+H; layer = <CALayer: 0x6000014bdc60>> location in window: {165.66665649414062, 232.33332824707031} previous location in window: 
{165.66665649414062, 232.33332824707031} location in view: {165.66665649414062, 
232.33332824707031} previous location in view: {165.66665649414062,232.33332824707031}
)}