在appdelegate中呈现多个模态视图

Question

我想在应用程序收到的每个推送消息之后呈现一个modalviewcontroller:"应用程序:(UIApplication*)应用程序didReceiveRemoteNotification:(NSDictionary*)userInfo"

我像这样呈现viewcontroller:

ReleaseViewController *viewController = [[ReleaseViewController alloc] init];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:viewController];
[self.window.rootViewController presentModalViewController:navController animated:YES];

所以当另一个推送消息到来并且旧的ModalViewController仍然是可见的时,我想在旧的上呈现一个新的modalviewcontroller.但它不起作用.没有发生任何事情,控制台只是说(我认为这是iOS 6 Beta的调试消息):

Warning: Attempt to present <UINavigationController: 0x1dde6c30> on <UINavigationController: 0x1dd73c00> whose view is not in the window hierarchy!

我究竟做错了什么？

PS:我不想解雇旧的ViewController,我希望它们能够堆叠.

谢谢!

Answer 1

您可以获得视图控制器的顶部,然后从该顶视图控制器呈现新模态

- (UIViewController *)topViewController:(UIViewController *)rootViewController
{
    if (rootViewController.presentedViewController == nil) {
        return rootViewController;
    }

    if ([rootViewController.presentedViewController isMemberOfClass:[UINavigationController class]]) {
        UINavigationController *navigationController = (UINavigationController *)rootViewController.presentedViewController;
        UIViewController *lastViewController = [[navigationController viewControllers] lastObject];
        return [self topViewController:lastViewController];
    }

    UIViewController *presentedViewController = (UIViewController *)rootViewController.presentedViewController;
    return [self topViewController:presentedViewController];
}

你可以用rootViewController调用这个方法是window的rootViewController