Question

presentedViewController和presentingViewController的区别

Answer 1

presentingViewController是指 presented this view controller(modally)

所以通常viewControllerA ---(modally)--> viewControllerB, 设置A = B.delegate, 想要在A中使得B消失，则用
[self.presentedViewController dismissViewControllerAnimated:YES completion:nil];

另外，push对应的是pop。比如：
[self.navigationController popViewControllerAnimated:YES];