模态视图控制器不在窗口层次结构中

Question

我试图做的应用程序有一个tabbar控制器.

当应用程序启动时,我将获得AppDelegate中的用户位置,当我获得准确性时,我需要AppDelegate将NSNotification发送到我的应用程序的起始页面(标签栏控制器的索引0).

收到通知后,此视图会尝试发送包含用户坐标和其他数据的电子邮件,但只要出现MFMailComposeViewController,我就会收到以下错误:

Warning: Attempt to present <MFMailComposeViewController: 0x98a0270> on <UITabBarController: 0x988c630> whose view is not in the window hierarchy!

我错过了什么？

谢谢.

编辑:添加一些代码......

这是我在AppDelegate.m中得到的:

- (void) locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
NSUserDefaults *phoneNumbers = [NSUserDefaults standardUserDefaults];
NSDate *eventDate = newLocation.timestamp;
NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
if (abs(howRecent) < 10.0) {
    [self locationUpdate:newLocation];
    smsLoc = newLocation;
    if ([[phoneNumbers objectForKey:@"sendSMS"] isEqualToString:@"yes"]) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"sendSMS" object:nil];
    } else if ([[phoneNumbers objectForKey:@"sendEmail"] isEqualToString:@"yes"]) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"sendEmail" object:nil];
    }

}
}

然后,在我的第一个视图控制器中,我有:

- (void)viewDidLoad
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sendSMS:) name:@"sendSMS" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sendEmail:) name:@"sendEmail" object:nil];
}

最后,"sendSMS"的选择器(另一个非常相似):

- (void)sendSMS: (NSNotification *)notification {
NSUserDefaults *phoneNumbers = [NSUserDefaults standardUserDefaults];
if ([phoneNumbers objectForKey:@"first"] || [phoneNumbers objectForKey:@"second"]) {
        MFMessageComposeViewController *controller = [[MFMessageComposeViewController alloc] init];
        if ([MFMessageComposeViewController canSendText]) {
            AppDelegate *deleg = (AppDelegate *)[[UIApplication sharedApplication] delegate];
            controller.body = [NSString stringWithFormat:@"some message with coordinates %.4f - %.4f", [deleg currentLocation].coordinate.latitude, [deleg currentLocation].coordinate.longitude];
            controller.recipients = [NSArray arrayWithObjects:[phoneNumbers objectForKey:@"first"], [phoneNumbers objectForKey:@"second"], nil];
            controller.messageComposeDelegate = self;
            [self presentModalViewController:controller animated:YES];
        }
    }
}
}

第二次编辑:添加更多代码.

UITabBarController *tabBarController = [[UITabBarController alloc] init];
tabBarController.delegate = self;
tabBarController.selectedIndex = 0;
[[tabBarController.tabBar.items objectAtIndex:0] setTitle:NSLocalizedString(@"Home", nil)];
[[tabBarController.tabBar.items objectAtIndex:1] setTitle:NSLocalizedString(@"Requests", nil)];
[[tabBarController.tabBar.items objectAtIndex:2] setTitle:NSLocalizedString(@"Account", nil)];
[[tabBarController.tabBar.items objectAtIndex:3] setTitle:NSLocalizedString(@"Settings", nil)];
//some other controls from DB
[[tabBarController.tabBar.items objectAtIndex:1] setBadgeValue:[NSString stringWithFormat:@"%d",number]];

tabbarController是通过IB制作的,但我在AppDelegate中添加了上面的代码,因为我需要本地化标签栏项目并为其中一个添加徽章.我在这里做错了吗？

Answer 1

我不确定你是否解决了这个问题.错误消息表示用于呈现另一个模态viewcontroller的viewcontroller在窗口中不可见.这可能发生在例如:

[VC1 presentModalViewController:VC2];

// Error here, since VC1 is no longer visible on the window
[VC1 presentModalViewController:VC3]; 

如果您的问题如上所述,您可以修复它:

if (self.modalViewController != nil) {
    [self.modalViewController presentModalViewController:VC3 animated:YES];
} else {
    [self.tabBarController presentModalViewController:VC3 animated:YES];
}

如果这不能解决您的问题,也许您可​​以尝试使用self.tabBarController而不是self来呈现.再一次只是建议,不知道它是否有效.