如何让子视图控制器将 UISearchBar 添加到父级的 UINavigationController？

Question

How to let child view controller modify navigation controller?

I am faced with this problem right now, and have not been able to find a solution that works, let alone one that works well.

Basically, right now I have a UINavigationController that contains a UITableViewController with a search bar in the navigation bar. So far so good - everything works well.

However, I would like to show some custom views between the navigation bar and the top of the table view at times. To do this, I figured it would be best to create another view controller (let's call it the ContainerViewController ), which is presented by the navigation controller. This container view controller holds the table view controller as a child, and can insert any custom view it wishes to. The view controller hierarchy should look like this:

UINavigationController
    ContainerViewController
        UITableViewController (with UISearchDisplayController)

Now I am faced with a problem, since the search bar of the UISearchDisplayController should be displayed in the navigation bar (by calling didSetupSearchDisplayController ), but I obviously want all logic pertaining to it kept in the UITableViewController . I need the container view controller to sort of act as a go-between here. I have tried to figure this out, but haven't managed a solution yet.

Here is how I instantiate the table view controller and add it as a child in the container view controller.

- (void)viewDidLoad {
    [super viewDidLoad];

    // Load view controller from storyboard
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];
    self.contentViewController = [storyboard instantiateViewControllerWithIdentifier:@"MyListViewController"];
    self.contentViewController.view.translatesAutoresizingMaskIntoConstraints = NO;

    // Add its view to the content view
    [self addChildViewController:self.contentViewController];
    [self.container addSubview:self.contentViewController.view];
    [self.contentViewController didMoveToParentViewController:self];

    // Set up constraints
    [self.contentViewController.view autoPinEdgesToSuperviewEdgesWithInsets:UIEdgeInsetsZero];
}

In the child view controller, I have noticed that self.navigationController is nil in viewDidLoad but not in didMoveToParentViewController . So the following works:

- (void)didMoveToParentViewController:(UIViewController *)parent {
    // Hide separator below navigation bar
    self.navigationController.navigationBar.clipsToBounds = YES;
}

But I cannot set the search bar to display in the navigation bar, nor can I set the navigation bar title (with self.title = ... ) from within the child view controller.

Would appreciate any help.

EDIT: Here is some code I use in the UITableViewController (the contained view) to create the search display controller:

UISearchBar *searchBar = [[UISearchBar alloc] init];
self.mySearchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchBar contentsController:self];

// Show search bar in navigation bar (instead of in its own bar underneath)
self.searchDisplayController.displaysSearchBarInNavigationBar = YES;

// Set self as delegate to search display controller and its table view
self.searchDisplayController.delegate = self;
self.searchDisplayController.searchResultsDelegate = self;

I have tried doing this both in viewDidLoad , where the self.navigationController is nil, and in didMoveToParentViewController , where the navigation controller exists, but it does not seem to matter. My guess is that the displaysSearchBarInNavigationBar magic happens after the child view is instantiated but before it is added as a child view (and thus gets access to the navigation controller).

Answer 1

can you use

self.parentViewController.navigationController

to get the reference to the navigation controller from within the container view?

Answer 2

This may help you find your answer. We use this to set the title of our navigation controller

self.navigationItem.title=@"Name of view goes here";

You should be able to use self.navigationItem to get a handle to the navigation bar.