导航栏不会出现在iOS7.1中使用show（push）segue

Question

我有三个iOS版本的设备。我隐藏导航栏RootViewController。然后，对于每个ViewController，我显示导航栏作为

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    self.view.userInteractionEnabled = YES; 
    // Do any additional setup after loading the view. 
    [self.navigationController setNavigationBarHidden:NO]; 
    CGRect frame = CGRectMake(0, 0, 0, 44); 
    UILabel *label = [[UILabel alloc] initWithFrame:frame]; 
    label.backgroundColor = [UIColor clearColor]; 
    label.font = [UIFont fontWithName:@"Helvetica-Bold" size:20.0]; 
    label.textAlignment = NSTextAlignmentCenter; 
    label.textColor = [UIColor blackColor]; 
    label.text = @"Update Height"; 
    self.navigationItem.titleView = label; 
} 

它的工作原理与iOS8.4和iOS9.1两个设备，但不能用于iOS7.1。对于iOS7.1设备，如果将segue更改为自定义类型，则会显示导航栏。但如果我更改为显示（推）segue，导航栏不显示。 可能是什么问题？ 我从UIStoryBoard使用segue。 感谢

Answer 1

阅读本link，然后尝试这个

//hide on current view controller 
    - (void)viewWillAppear:(BOOL)animated { 
    [super viewWillAppear:animated]; 
    [self.navigationController setNavigationBarHidden:YES animated:YES]; 
} 

// show on next view controller 
- (void)viewWillDisappear:(BOOL)animated { 
    [super viewWillDisappear:animated]; 
    [self.navigationController setNavigationBarHidden:NO animated:YES]; 
}