CODEWITHSUNDEEP
iosobjective-caccessibilityvoiceover
Jkkarr
Jkkarr

Reputation: 422

How to get correct screen coordinate from UITapGestureRecognizer while VoiceOver is on

I'm currently working on an interactive view that relies heavily on the user's touch location. I have found that there are a few ways to interact with the UITapGestureRecognizer while VoiceOver is on, but when I tap my point the values given are very wrong. I've looked elsewhere, but my use case is outside of the norm so there is not a lot to tell me what is going on. Has anyone experienced this before?

I am aware that I can change accessibilityTrait to UIAccessibilityTraitAllowsDirectInteraction which will give me the correct screen point when used, but I would like to know what is causing this issue at the very least for the sake of knowledge. To interact with the UITapGestureRecognizer I either double tap or do a 3D touch by pressing on hard on the screen. The ladder method doesn't work for the tap gesture but will work for the pan gesture.

This is the only line I use to get my screen points. My map view is a UIImageView

CGPoint screenPoint = [tapGesture locationInView:map];

I'm using a map of a building and I try to tap the same corner or landmark for my testing. I know I can't hit the same exact point every time, but I do use a stylus and I can get pretty close.

Without VoiceOver on I would get the result: (35.500, 154.363)

With VoiceOver on and tapping in generally the same spot, I get : (187.500, 197.682)

The point I am using to test is on the left side of the screen and the result from VoiceOver being on is in the middle of the screen. I believe the y-axis value may have changed because of my tool bar's size, but I have no idea what is throwing off the x-axis value. If more information is needed let me know.

UPDATE: Upon further investigation, it turns out that the UITapGestureRecognizer will always return (187.500, 197.682) no matter where I touch in the map view when VoiceOver is on. That point seems to be the middle of the map view. Oddly enough though, the UIPanGestureRecognizer will give me the correct (x,y) for my view if I use the 3D touch while VoiceOver is on.

On a side note not relating to the problem at hand, it seems if I use the accessibility trait UIAccessibilityTraitAllowsDirectInteraction the method UIAccessibilityConvertFrameToScreenCoordinates returns a frame that is higher than my view. It works fine if I do not change the trait.

Upvotes: 2

Views: 405

Answers (1)

XLE_22
XLE_22

Reputation: 5671

Your problem may deal with the reference point used when VoiceOver is on. Verify what your point coordinates are referring to : view or screen coordinates ?

I suggest you take a look at the following elements :

According to your project, the previous elements may be interesting to get your purposes.

Upvotes: 0

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