正如 Eric 在他的评论中所说,使用 MBProgressHud 加载视图。
将 HUD 添加为窗口的子视图。
    // Should be initialized with the windows frame so the HUD disables all user input by covering the entire screen
    HUD = [[MBProgressHUD alloc] initWithWindow:[UIApplication sharedApplication].keyWindow];
    // Add HUD to screen
    [self.view.window addSubview:HUD];
    // Register for HUD callbacks so we can remove it from the window at the right time
    HUD.delegate = self;
    HUD.labelText = NSLocalizedString(@"Loading Workbench", nil);
    HUD.detailsLabelText = NSLocalizedString(@"please wait", nil);
    // Show the HUD while the provided method executes in a new thread
    [HUD showWhileExecuting:@selector(loadWorkbench:) onTarget:self withObject:nil animated:YES];
添加以下委托方法:
- (void)hudWasHidden {
    // Remove HUD from screen 
    [HUD removeFromSuperview];
    // add here the code you may need
}
也不要忘记添加MBProgressHUDDelegate相应的头文件。