導航欄不會出現在iOS7.1中使用show（push）segue

Question

我有三個iOS版本的設備。我隱藏導航欄RootViewController。然後，對於每個ViewController，我顯示導航欄作爲

- (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; 
} 

它的工作原理與iOS8.4和iOS9.1兩個設備，但不能用於iOS7.1。對於iOS7.1設備，如果將segue更改爲自定義類型，則會顯示導航欄。但如果我更改爲顯示（推）segue，導航欄不顯示。 可能是什麼問題？ 我從UIStoryBoard使用segue。 感謝

Answer 1

閱讀本link，然後嘗試這個

//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]; 
}