Why is not updated currentPage indicator on UIPageControl?

问题

I am using the following code to update the currentPage indicator in my app:

pgcNotification.currentPage = 3;
pgcNotification.numberOfPages = 4;

Though, the indicator never changes and always stays in its first position.

回答1:

The problem is that you, firstly have to say the amount of pages and secondly the current page. Never in the other way around.

pgcNotification.numberOfPages = 4;
pgcNotification.currentPage = 3;

来源：https://stackoverflow.com/questions/28783361/why-is-not-updated-currentpage-indicator-on-uipagecontrol