无法在iOS中获得任何导航项目

Question

I have a question regarding the navigation bar.

As far as I understand from iOS: A view controller opened by a segue inherits the navigation bar of the parent view controller. Is this correct so far?

Is there a view controller within a stack "owns" the navigation bar in a complex segue stack (eg TableViewController that opens a TabBarController that opens ...)?

I very often run into the problem that I don't know where to get the actual navigation item in order to set the title or a bar button item.

In this case, I have the following controllers:

• TabBarController
• EventPostsViewController -> To display a list of posts, is a tabbed view within the TabBarController
• CreatePostViewController -> To write a new post

So within the EventPostsViewController I can do this (and it works):

class EventPostsViewController: UITableViewController {
    ...
    override func viewWillAppear(animated: Bool) {
        ...
        // This solution works, but only for EventPostsViewController
        self.tabBarController?.navigationItem.title = "text"

But within the CreatePostViewController , which is opened by a segue via EventPostsViewController , neither of this solutions work.

class CreatePostViewController: UIViewController {
    ...
    override func viewWillAppear(animated: Bool) {
        ...
        // Neither of these solutions works
        self.navigationItem.title = "Text"
        self.tabBarController?.navigationItem.title = "Text"
        self.navigationController?.navigationItem.title = "Text"

How do I get the actual navigation bar/navigationItem?

Answer 1

Stupid simple mistake I repeat every time :)

I forgot to link my custom CreatePostViewController with the view controller using the interface builder.

This code now works:

class CreatePostViewController: UIViewController {
    ...
    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated);
        self.navigationController?.setNavigationBarHidden(false, animated: false)

        // Set title
        self.navigationItem.title = "Write Post"

        // Add Submit button
        var submitButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Done, target: self, action: "submitPost:")
        self.navigationItem.rightBarButtonItem = submitButton
    }
    ...
}