APP启动时控制台输出unexpected nil window in _UIApplicationHandleEventFromQueueEvent

appDelegate中，将：
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
[self.window makeKeyAndVisible];
改为：
self.window = [[UIWindow alloc] init];
[self.window makeKeyAndVisible];
self.window.frame = [[UIScreen mainScreen] bounds];

参考于：

http://www.bubuko.com/infodetail-391693.html