Associating a Realm Object with a UITabBarController in iOS 9 with RealmSwift - ios

Question

Below is a screenshot of the storyboard for my project:
As you can see, I have a UIViewController with a UITableView embedded in a UINavigationController. When the user adds an item to the UITableView a new Realm Object model which I have named Project is created (I'm using RealmSwift) and they are taken to the first item in the UITabBarController. I'm wondering if it is possible to associate the UITabBarController and all of its child view controllers with the Project that is created.
Here is the code that creates the Object (which is working fine):
func add(withName projectName: String) {
let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
dispatch_async(queue) {
autoreleasepool {
let realm = try! Realm()
let newProject = Project(value: ["name": projectName, "date": NSDate()])
realm.write({ () -> Void in
realm.add(newProject)
})
}
}
}
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
tableView.deselectRowAtIndexPath(indexPath, animated: true)
selectedProject = array[indexPath.row]
print(selectedProject)
self.performSegueWithIdentifier("showTab", sender: self)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showTab" {
let dvc = segue.destinationViewController as! TabBarViewController
dvc.project = selectedProject
}
}
As you can see, I'm passing the new Project to the UITabBarController.
Here is my code in the UITabBarController:
import UIKit
import RealmSwift
class MasterTabViewController: UITabBarController {
var project: Project?
override func viewDidLoad() {
super.viewDidLoad()
configureNavigationBar()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
// MARK: - UI Styling
private extension MasterTabViewController {
func configureNavigationBar() {
navigationItem.title = project?.name
}
}
This sets the title of all UIViewControllers that descend from the UITabBarController.
Is there a way for me to make that Project object available to all view controllers that descend from the UITabBarController? I haven't been able to find too much information on this. One suggestion that I found was to store the Object in NSUserDefaults but it seems to me that there must be a better way.
EDIT: I forgot to add that I can think of a way to do this with Core Data using NSManagedObjectContext, but I'm having some trouble seeing the equivalent in Realm.

Answer 1

You were on the right track! When a view controller is a child of a UITabBarController, you can access the tab bar controller from inside the child view controller with the self.tabBarController property.
Since you know these view controllers are children of a subclass of UITabBarController that also provides Project as a property, it should be a matter of simply calling that tab bar controller property, typecasting the resulting view controller to your tab bar controller subclass, and then calling the project property on it.
So, in any of your child controllers:
let project = (self.tabBarController as MasterTabViewController).project?
You could easily optimize this further by making project a read-only property of your child controller classes that calls this line of code automatically. Good luck!