打印调用的顺序：
TestFunctionCall[49445:60b] ---> -[ZQRootViewController viewDidLoad]
TestFunctionCall[49445:60b] ---> -[ZQCustomView initWithFrame:]
TestFunctionCall[49445:60b] ---> -[ZQRootViewControllerview WillLayoutSubviews]
TestFunctionCall[49445:60b] ---> -[ZQRootViewControllerview DidLayoutSubviews]
TestFunctionCall[49445:60b] ---> -[ZQCustomView layoutSubviews]
TestFunctionCall[49445:60b] ---> -[ZQCustomView layoutSubviews]
TestFunctionCall[49445:60b] ---> -[ZQCustomView drawRect:]
先调用试图控制器的viewWillLayoutSubviews 以及viewDidLayoutSubviews，然后调用view的layoutSubviews、layoutSubviews 。最后调用drawRect
