Custom button bar with custom back navigation button - objective-c

Question

Reusable button bars? gets me part of the way here, but now I'm having trouble with the "back button" requirements.
I need a layout solution that:
will work on iOS 5.0 and 6.0
has a custom view at the top with several buttons; this view should be reusable across every screen (scene), as opposed to duplicating the buttons manually in Interface Builder for each scene.
has a custom "back" button in that top custom view. With the design I have to implement, I cannot just use the default navigation bar
works well with the UINavigationController; when the user taps the "back" button, the main view controller (with the button bar) should stay, but the child view controller representing the actual scene content should go back to the previous scene.
The problem currently is that the "back" button won't change the child controller--it changes the parent controller, returning to the previous scene before the scene with the button bars. I've tried this several different ways. I'm not sure if I'm not doing it right, or if it can't be done.
One possibility is to implement my own "back" functionality, keeping a stack of child view controllers and manually changing them when the user taps "back." This is awkward, however, and poor design compared to using UINavigationController.
Perhaps I am going the wrong way with this. I can't accept duplicating the button bar across every single scene in Interface Builder... but perhaps I should create it programmatically, and then I can easily call that code from each and every scene. Then I would have "normal" view controllers, and using UINavigationController would be easier. But before I go that route and completely scrap what I have so far, I wanted to see if there was another way.
Here's an overview of some parts of my solution:
I created a ButtonBarController, laying out the Storyboard with a UIView for the buttons I wanted, and a UIView for the content pane. I also layered a button with the app logo (to go to the app's main screen) on top of a back button.
Then I created a controller for each of those other screens. In those subscreens/child view controllers, I would first add a UIView at the correct size to fit in my content pane, and then would add all the other controls I wanted. I had all of those child view controllers inherit from another controller, which took care of a few common tasks--such as procuring a reference to the button bar controller, and code to help resize the views for 3.5" versus 4" screens.
I created a changeToControllerWithIndex method; I call this when the app loads, when the user clicks one of the buttons in the main button bar to change scenes, or when anything happens in a scene requiring another scene change. I overload this method to provide two additional pieces of information: providing an NSDictionary with any extra information the child view controller needs, and to tell it whether this is a top-level scene, or whether we need a back button.
(Note: it's important to set the Storyboard ID for those child view controllers in the Identity Inspector. I kept accidentally setting the Title in the Attribute Inspector instead)
- (void)changeToControllerWithIndex:(NSInteger)index {
[self changeToControllerWithIndex:index withPayload:nil isRootView:YES];
}
// This is the method that will change the active view controller and the view that is shown
- (void)changeToControllerWithIndex:(NSInteger)index withPayload:(id)payload isRootView:(BOOL)isRootView
{
if (YES) {
self.index = index;
// The code below will properly remove the the child view controller that is
// currently being shown to the user and insert the new child view controller.
UIViewController *vc = [self setupViewControllerForIndex:index withPayload:payload];
if (isRootView) {
NSLog(#"putting navigation controller in");
childNavigationController = [[UINavigationController alloc] initWithRootViewController:vc];
[childNavigationController setNavigationBarHidden:YES];
[self addChildViewController:childNavigationController];
[childNavigationController didMoveToParentViewController:self];
if (self.currentViewController){
[self.currentViewController willMoveToParentViewController:nil];
[self transitionFromViewController:self.currentViewController toViewController:childNavigationController duration:0 options:UIViewAnimationOptionTransitionNone animations:^{
[self.currentViewController.view removeFromSuperview];
} completion:^(BOOL finished) {
[self.currentViewController removeFromParentViewController];
self.currentViewController = childNavigationController;
}];
} else {
[self.currentView addSubview:childNavigationController.view];
self.currentViewController = childNavigationController;
}
[self.currentView addSubview:childNavigationController.view];
//We are at the root of the navigation path, so no back button for us
[homeButton setHidden:NO];
[backButton setHidden:YES];
} else {
//Not a root view -- we're in navigation and want a back button
[childNavigationController pushViewController:vc animated:NO];
[homeButton setHidden:YES];
[backButton setHidden:NO];
}
}
}
Then I have an overloaded method to set up each individual view controller... some require a little more preparation than others.
- (UIViewController *)setupViewControllerForIndex:(NSInteger)index {
return [self setupViewControllerForIndex:index withPayload:nil];
}
// This is where you instantiate each child controller and setup anything you need on them, like delegates and public properties.
- (UIViewController *)setupViewControllerForIndex:(NSInteger)index withPayload:(id)payload {
UIViewController *vc = nil;
if (index == CONTROLLER_HOME){
vc = [self.storyboard instantiateViewControllerWithIdentifier:#"Home"];
} else if (index == CONTROLLER_CATEGORIES){
SAVECategoryViewController *child = [self.storyboard instantiateViewControllerWithIdentifier:#"Categories"];
if (payload) {
child.currentCategory = [(NSNumber *) [(NSDictionary *)payload objectForKey:ATTRIBUTE_CAT_ID] integerValue];
} else {
child.currentCategory = CATEGORY_ALL;
}
vc = child;
} //etc for all the other controllers...
payload = nil;
return vc;
}
I mentioned my difficulty with managing the "back" navigation. The above code ensures the navigation controllers maintain a proper "back" history, starting fresh whenever we use one of the button bar buttons to change screens. When we do use buttons inside a child controller to navigate from scene to scene, this is how we can go back:
- (IBAction)backButtonPressed:(id)sender {
[childNavigationController popViewControllerAnimated:YES];
if ([[childNavigationController viewControllers] count] <= 1) {
//Root view
[homeButton setHidden:NO];
[backButton setHidden:YES];
}
}

Answer 1

I think you need to implement at least one custom container view controller - the root view controller. That would be the one to host the custom button bar. Below the button bar you would add a UINavigationController the manage your other VCs. Look at this for starters:
#implementation RootVC
//...
- (void)viewDidLoad
{
self.navVC = [[UINavigationController alloc] initWithRootViewController:someOtherVC];
self.navVC.navigationBarHidden = YES;
self.navVC.view.frame = ...;
[self addChildViewController:self.navVC];
[self.view addSubview:self.navVC.view];
[self.navVC didMoveToParentViewController:self];
}
- (void)backButtonTouched:(UIButton *)button
{
[self.navVC popViewControllerAnimated:YES];
}