ios - 其 View 不在NSNotification的窗口层次结构中

我有错误
其视图不在窗口层次结构中!

当我是NSnotification

- (void) receiveTestNotification:(NSNotification *) notification
{


    if ([[notification name] isEqualToString:@"TestNotification"])
        NSLog (@"Successfully received the test notification!");


    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    mainTabViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"passID"];
    [vc setModalPresentationStyle:UIModalPresentationFullScreen];

    [self presentViewController:vc animated:YES completion:nil];

}

最佳答案

如果您想在单元格内显示 Activity 视图，
也许在标题旁边，您可以使用类似

 UIActivityIndicatorView *activityView = [[UIActivityIndicatorView alloc]     initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
  [cell.imageView addSubview:activityView];
  [activityView startAnimating];