覆盖UINavigationController中的后退按钮

Question

I'm fairly new to iOS development and am working on my first app. My app has 3 main views, the first is the login screen (which allows users to login to the web service), the second is a submit screen (which allows users to submit content to the web service) and the last is the settings view (which among other things allows users to log out of the app).

I'm storing the user credentials in Keychain as good practice, and so that the user can stay logged in and usually when they open the app they can just go to the submit content page. As such the submit view is essentially my main view.

To access the settings I have a small gear button on the submit view that will take a user to the settings page. On the settings page I have a log out button that deletes your username and password from keychain.

So if you've logged out of the app I want the back button to take you to the login view if not it should take you back to the submit view, but I can't seem to control what the back button takes the user.

I know Apples guidelines say not to do something like this but this seems like an obvious design choice. How would I override the back button's action on the navigation bar?

Answer 1

Simply hide the navigation bar and put your custom navigation bar and write what ever name you want to button and provide back button action using [self.navigationController popViewControllerAnimated: YES]; or choose whatever view controller your want..

OR

You can simply create Subclass of NavigationController and override method popViewControllerAnimated:

Answer 2

It would be easy for you to save user information in user default instead of keychain. When user login add this

[[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"UserAlreadyRegister"];

When user logout add this

[[NSUserDefaults standardUserDefaults] setBool:NO forKey:@"UserAlreadyRegister"];

And the put following code in view did appear of your submit view

-(void)viewDidAppear:(BOOL)animated{
    BOOL alreadyRegister = [[NSUserDefaults standardUserDefaults] boolForKey:@"UserAlreadyRegister"];
    if (alreadyRegister){
        [self.navigationController popViewControllerAnimated:YES];
    }
}