Presenting view controllers on detached view controllers is discouraged

解决方法- (void)viewDidAppear:(BOOL)animated 

{ 

[super viewDidAppear:animated]; 

[self presentViewController:[[YourViewController alloc] init] animated:YES completion:NULL]; 

}

或者：

- (void)viewDidLoad 

{ 

[super viewDidLoad]; 

dispatch_async(dispatch_get_main_queue(), ^{ 

YourViewController *v = [[YourViewController alloc] init]; 

[self presentViewController:v animated:YES completion:^{}]; 

}); 

}