What gets called instead of - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event when Accessibility(voice over is on)

Question

Recently I have put a breakpoint in a UIViews method

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {

}

method and checked if the compiler stops here when a user taps on the UIView while voiceover is on, but it never came to the breakpoint, does anyone know what gets called and how the touch can be intercepted?

Answer 1

First of all, note that users must double-tap to "activate" or "tap" a view when VoiceOver is enabled. If you still aren't hitting hitTest:…, then break on acccessibilityActivate(). This is the default accessibility action triggered by a double-tap. You may also be interested in the activationPoint, which is the default location of the simulated touch VoiceOver emits upon activation. Note that the activation point isn't relevant to all VoiceOver interactions (eg. adjustable controls).

Answer 2

The hit-test view is given the first opportunity to handle a touch event. If the hit-test view cannot handle an event, the event travels up that view’s chain of responders as described in “The Responder Chain Is Made Up of Responder Objects” until the system finds an object that can handle it. Please look at this.

Answer 3

The standard hitTest mechanism is not used when VoiceOver is on. Instead, UIView has an _accessibilityHitTest:withEvent: method, but unlike macOS, it is private and can't easily be overridden or called.

Similar to hitTest, _accessibilityHitTest uses _accessibilityPointInside:withEvent:, which, in turn, calls pointInside:withEvent: (which is public).