仅当当前segue的parentController为X时，才如何展开到rootViewController？

Question

My App has a total of 4 ViewControllers in a NavigationViewController: A,B, C and D. From ViewController A it is possible to go to B and C. From both B and C it is possible to go to D. In other words:

A --> B --> D
A --> C --> D

What I want to do is, when the user presses back in D, I want to go to the rootViewController (A) only if the previous ViewController was B. If the previous ViewController was C, I want to go back to C.

I'm fairly new to iOS and this is my first app so I'm not sure what the best way to do this is. Your help would be appreciated.

Answer 1

You can set some property in viewControllerD - 'needToGoBackHome'

In your viewControllerB:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    ViewControllerD *vcd =  (ViewControllerD *)segue.destinationViewController;
    vcd.needToGoBackHome = YES;
}

In your viewControllerD - override the back behavior of the navigation if need to:

- (void)viewDidLoad 
{
    [super viewDidLoad];

    if (self.needToGoBackHome) {
        UIBarButtonItem *newBackButton = [[UIBarButtonItem alloc] initWithTitle:@"Home" style:UIBarButtonItemStyleBordered target:self action:@selector(goBackToA:)];
        self.navigationItem.leftBarButtonItem=newBackButton;
    }
}

- (void)goBackToA:(id)sender
{
    [self.navigationController popToRootViewControllerAnimated:YES];
}

edit

Of course, if you have more than one segue from viewControllerB, you need to set the segue's identifier, and check if it is the right segue in the 'prepareForSegue' method