Sometimes uigesturerecognizer gesture can not be identified problem analysis and solutions

Sometimes the uigesturerecognizer that we add cannot be identified, and the reason for analysis is at least three possible:

1. -(BOOL) Gesturerecognizer: (Uigesturerecognizer *) Gesturerecognizer Shouldrecognizesimultaneouslywithgesturerecognizer: (Uigesturerecognizer *) Othergesturerecognizer;
2. -(BOOL) Gesturerecognizershouldbegin: (Uigesturerecognizer *) Gesturerecognizer;
3. -(BOOL) Canbepreventedbygesturerecognizer: (Uigesturerecognizer *) Preventinggesturerecognizer;

corresponding serial number, respectively explained:

1. A gesture action that may trigger multiple gestures, this interface asks if these gestures can coexist.
2. eg: a transverse scrollview A, with a vertical self-scrollview B, an oblique swipe gesture (intended to be horizontal), may only respond to the vertical slide of B, and the horizontal of a you expect does not occur.
3. Solution: Identify your gesture in this interface and return YES. Be careful not to magnify it.
4. Gestures may occur, such as in some special cases, do not want to let this gesture occur, return No.
5. Some gestures didn't happen because they were blocked by other gestures. Typically like uitapgesturerecognizer gestures, a uitapgesturerecognizer never blocks a higher tap count UITapGestureRecognizer.

Sometimes uigesturerecognizer gesture can not be identified problem analysis and solutions