举手指时如何检测意外触摸？

Question

When i drag my finger, my app shows the finger's exact coordinates.

When i lift the finger the coordinates change a bit. They shouldn't.

This only happens when the finger is a thumb and it does happen because when i lift it, the iPad senses one or two more touches (calls touchesMoved) before touchesEnded gets called.

I tried to detect this by checking big pathMajorRadius changes but it's not effective because these changes can also occur when doing regular dragging movements.

So, i ask, how to reliably detect unintentional touches when lifting a finger off the iPad?

If you need more data, please ask.

Answer 1

To check number of touches on screen, you can do the following. In the touchesBegan, touchesMoved, and touchesEnded methods, one parameter is event, which is a UIEvent object. The number of fingers on the screen is [[event allTouches]count]. So if number of touches greater than one, you can edit code so that it wont be taken into consideration.