Btn Demo touch Error [only tested btn]

while I use the btn example 2【it may prove touch and dipaly driver is fine】, the touch is ok,and the callback function was executed.
But the others example just can only display but can’t touch, and the callback function wasn’t executed.
And I try to delete some function and some variable, found that【as the picture show】

and run the project.the callback function was be called successfullly.And as the next picture to show.

if delete one of the variable and function in the first picture, nothing to display.
My English is bad,sorry.
And the forum can’t Preview markdown?

A stupid mistake.I didn’t give enough stack size for the thread.So touch didn’t work.