Showing two UIViewController at the same time
问题 I have two UIViewControllers which I sometimes need to show at the same time. Imagine ViewController A only has one button and is otherwise transparent. Once I touch the button I would like ViewController B (which is green) to fade in and do other custom animations, but ViewController A (and the button) needs to be still shown on top of B. Once the fade/animation etc. are over, only ViewController B (green) is visible. My questions: 1) What is the best setup? UINavigationController with