Back button does not appear in navigation bar until you rotate - iphone

Question

I have three view controllers: A -> B -> C managed by a navigation controller. A is a transient view controller. It asks the server for something. If the server says everyhing is OK, then A pushes B onto the stack. B must hide the back button because I don't want users to manually go back to A.
// B view controller
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationItem.hidesBackButton = YES;
self.title = #"B";
}
B then pushes C onto the stack when the user taps a table cell.
// B view controller
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
C *c = [[C alloc]
initWithStyle:UITableViewStyleGrouped
];
[self.navigationController
pushViewController:c
animated:YES
];
[c release];
}
.
// C view controller
- (void) viewDidLoad
{
[super viewDidLoad];
self.navigationItem.hidesBackButton = NO;
self.title = #"C";
}
If all goes well, the flow should look like this:
------------- ------------- -------------
|_____A_____| |_____B ____| | <B|__ C___|
| | => | | => | |
| loading...| | cells | | detail |
| | | | | |
------------- ------------- -----------
For some reason, C does not show a back button to go back to B until I rotate the device. Once rotated, the back button appears in all orientations. The problem seems to stem from B hiding the back button and C trying to reveal it again, because If I don't let B hide it, I don't have this problem. So how do I get C to show the back button without forcing the user to rotate the device like a monkey?
Update
Broken on two different Verizon iPhone 4 both on iOS 4.2.10
Fine on AT&T iPhone 3GS on iOS 5.0
Fine on AT&T iPhone 4 on iOS 4.3

Answer 1

After some searching I found this solution for iPhone 4.2 (since you posted that it works on later versions) on some old forum post.
-(void)viewDidLoad {
[super viewDidLoad];
self.navigationItem.hidesBackButton = YES;
}
-(void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
self.navigationItem.hidesBackButton = NO;
}
Mayhaps this will help you out.
(Check this out: Back button don't appear in navigationController)

Answer 2

I think you need to put your code like this for C
-(void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
self.navigationItem.hidesBackButton = NO;
}

Answer 3

I had this problem once and solved it by giving B's navigation item a title
// B view controller
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationItem.hidesBackButton = YES;
self.navigationItem.title = #"What you want C's back button to say";
self.title = #"B";
}
If you don't want the title to appear in B you can set B's navigationItem's titleView to an empty view. About the titleView property:
If this property value is nil, the navigation item’s title is displayed in the center of the navigation bar when the receiver is the top item. If you set this property to a custom title, it is displayed instead of the title. This property is ignored if leftBarButtonItem is not nil.

Answer 4

Try adding this to your class C:
-(id) init
{
[super init];
self.navigationItem.hidesBackButton = NO;
}

Answer 5

Not sure if this will work for your back button situation but I know that when I use a custom back button I need to set the custom back button on the alloc'd item before I push it (not self like the post above). Hopefully it will work for your situation as well - worth a try.
In other words, try:
// B view controller
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
C *c = [[C alloc]
initWithStyle:UITableViewStyleGrouped];
// *** set on c's navigationItem (not self) before you push
[[c navigationItem] setHidesBackButton: NO];
[self.navigationController
pushViewController:c
animated:YES
];
[c release];
}

Answer 6

Try to put self.navigationItem.hidesBackButton = NO; into the init method or anywhere before the pushViewController call.
ViewDidLoad is called when you ask the controller for the view for the first time, that means, it is probably called from [self.navigationController pushViewController:c animated:YES]. But note that the navigation bar is not part of your view, it is created and handled by UINavigationController, so basically it can exist and be drawn even before viewDidLoad and viewDidAppear is called. If you update navigation bar there, it doesn't get actually repainted.
Edit 1: Revisited after reading the documentation for [UIViewController navigationItem]
You should avoid tying the creation of bar button items in your navigation item to the creation of your view controller’s view. The navigation item of a view controller may be retrieved independently of the view controller’s view. For example, when pushing two view controllers onto a navigation stack, the topmost view controller becomes visible, but the other view controller’s navigation item may be retrieved in order to present its back button. To ensure the navigation item is configured, you can override this property and add code to load the bar button items there or load the items in your view controller’s initialization code.
Edit 2: Revisited after reading the comment that my solution does not work. Working code (iOS 5, ARC):
//
// TestAppDelegate.m
// NavigationTest
//
// Created by Sulthan on 10/25/11.
// Copyright (c) 2011 StackOverflow. All rights reserved.
//
#import "TestAppDelegate.h"
#interface TestAppDelegate ()
#property (nonatomic, strong, readwrite) UINavigationController* navigationScreen;
#property (nonatomic, strong, readwrite) UIViewController* screen1;
#property (nonatomic, strong, readwrite) UIViewController* screen2;
#property (nonatomic, strong, readwrite) UIViewController* screen3;
#end
#implementation TestAppDelegate
#synthesize window = window_;
#synthesize navigationScreen = navigationScreen_;
#synthesize screen1 = screen1_;
#synthesize screen2 = screen2_;
#synthesize screen3 = screen3_;
- (UIViewController*)createTestScreenWithLabel:(NSString*)label {
CGRect bounds = [[UIScreen mainScreen] bounds];
UIViewController* screen = [[UIViewController alloc] init];
screen.view = [[UILabel alloc] initWithFrame:bounds];
screen.view.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
((UILabel*) screen.view).textAlignment = UITextAlignmentCenter;
((UILabel*) screen.view).text = label;
return screen;
}
- (void)pushThirdScreen {
if (!self.screen3) {
self.screen3 = [self createTestScreenWithLabel:#"Screen 3"];
self.screen3.navigationItem.hidesBackButton = NO;
}
[self.navigationScreen pushViewController:self.screen3 animated:YES];
}
- (void)pushSecondScreen {
self.screen2 = [self createTestScreenWithLabel:#"Screen 2"];
self.screen2.navigationItem.hidesBackButton = YES;
UIBarButtonItem* button = [[UIBarButtonItem alloc] initWithTitle:#"Go"
style:UIBarButtonItemStyleBordered
target:self
action:#selector(pushThirdScreen)];
self.screen2.navigationItem.rightBarButtonItem = button;
[self.navigationScreen pushViewController:self.screen2 animated:YES];
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
CGRect bounds = [[UIScreen mainScreen] bounds];
self.screen1 = [self createTestScreenWithLabel:#"Screen 1"];
self.navigationScreen = [[UINavigationController alloc] initWithRootViewController:self.screen1];
self.window = [[UIWindow alloc] initWithFrame:bounds];
self.window.backgroundColor = [UIColor whiteColor];
[self.window addSubview:self.navigationScreen.view];
[self.window makeKeyAndVisible];
[self performSelector:#selector(pushSecondScreen) withObject:nil afterDelay:3.0];
return YES;
}
#end
Edit 3: Revisited after noticing that you are speaking mainly about iOS 4.2. I can't currently test it on any iOS 4.2 but I know about a possible workaround. You can always hide the navigation bar in your UINavigationController and just put a separate navigation bar into each screen. You will have absolute control over them and you can even edit them in Interface Builder.