UINavigationController Persistence

UINavigationController is one of the core building blocks on iOS. This category will allow you to save and load a UINavigationController's view controller stack. This will allow you to instantly return your users to their exact location in your app's view hierarchy.

Usage

Copy UINavigationController+Persistence.m and the corresponding header in to your Xcode project. Then simply import the category in any class you would like to use it.

#import "UINavigationController+Persistence.h"

Any time you would like to save the stack, call this method from any view controller in the stack:

[self.navigationController saveNavigationStack];

When your application starts up, you can check if you have a saved state like so:

// Class method
UINavigationController *navigationController = nil;

// Check for a saved state
if ([UINavigationController hasSavedStack]) {
    
    // Load the saved state
    navigationController = [[UINavigationController alloc] init];
    [navigationController loadNavigationStack];
} else {
    
    // Construct the starting state
    UIViewController *someViewController = [[UIViewController alloc] init];
    navigationController = [[UINavigationController alloc] initWithRootViewController:someViewController];
    [someViewController release];
}

Custom Paths

In case the default locations don't work for your application, or if you would like to persist multiple UINavigationController stacks, you may optionally pass an NSString as a path to serialize the data.

// Save to a custom path
[navigationController saveNavigationStack:@"/some/other/path/file.data"];
// Load from a custom path
[navigationController loadNavigationStack:@"/some/other/path/file.data"];