Presenting view controllers on detached view controllers is discouraged

Presenting view controllers on detached view controllers is discouraged <UINavigationController: 0x14642710>.的解决方法：

 [self.view.window.rootViewControllerpresentViewController:controller animated:YEScompletion:nil];

参考：http://stackoverflow.com/questions/19890761/warning-presenting-view-controllers-on-detached-view-controllers-is-discourage

Token 'string' not expected before outer-most array or object