unexpected nil window in _UIApplicationHandleEventFromQueueEvent...

unexpected nil window in _UIApplicationHandleEventFromQueueEvent, _windowServerHitTestWindow: <UIWindow: 0x7b8d6a60; frame = (0 0; 0 0); gestureRecognizers = <NSArray: 0x7b8d6780>; layer = <UIWindowLayer: 0x7b8d6a20>>

出现这个错误是因为没有设置窗口的frame

AppDelegate:

self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];