why does GestureRecognizer not work on textview first time?

Question

I have a textView to input some text or emotion. so I make another button to change the keyboard to custom emotion view, and I also use tap GestureRecognizer for when I want to change back to keyboard. I found every time I need to touch the button twice, the tap GestureRecognizer can work well. I thought and search long time but no result, finally I fix it. I think some one will meet the same question, so I shared it below.

Answer 1

because my add tap gesture recognition 's code is in init code, but when I tap textview, keyboard was pop up, the textview's position was changed too, so the init tap gesture recognition code isn't work now.

I fix it with add tap gesture recognition delay 0.3 s.