objective-c – 在segue之后的iOS 5黑屏

在场景1中,我需要传递一个变量,我这样做：

//Handles the selection 
-(void)tableView:(UITableView *)tableView accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath
{
    Guests *myGuests =[guestList objectAtIndex:[indexPath row]];

    selectedGuest = [[NSString alloc] initWithFormat:@"You have selected %@",myGuests.guestID];

    [self performSegueWithIdentifier:@"TGG" sender:self];
}

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    if([[segue identifier] isEqualToString:@"TGG"]){
        GuestDetailsViewController *vc = [segue destinationViewController];
        [vc setGuestSelected:selectedGuest];
    }
}

在场景2(详细信息)中,我使用它来验证是否收到了正确的变量

// Implement viewDidLoad to do additional setup after loading the view,typically from a nib.
- (void)viewDidLoad
{
    NSString *msg = [[NSString alloc] initWithFormat:@"You have selected %@",guestSelected];
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Selection" message:msg delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [alert show];          

     nameCell.textLabel.text= msg;

    [super viewDidLoad];
}

所有这一切都很好,警报框显示正确的变量,并有一个过渡到新场景.但是,警报框总共显示5次&结束,一旦完成,整个窗口都是黑色的.此时不显示我的场景(场景2).所以我知道我有正确的segue,它根据需要转换,我只是在屏幕上看不到任何东西.