Passing Data From AppDelegate to TableViewController Without NavigationBar

Question

I'm testing a Swift sample project by Apple, Inc. It's called Table Search with UISearchController . I've tried it. It runs. So I've made a sample from scratch in Swift 3. Anyway, the following is what I have.

class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Product is a data model class.
        let products = [
            Product(hardwareType: Product.deviceTypeTitle, title: Product.Hardware.iPhone.rawValue, yearIntroduced: 2007, introPrice: 599.00),
            Product(hardwareType: Product.deviceTypeTitle, title: Product.Hardware.iPod.rawValue, yearIntroduced: 2001, introPrice: 399.00), ...
        ]

        let navController = window!.rootViewController as! UINavigationController
        let tableViewController = navController.viewControllers.first as! MainTableViewController
        tableViewController.products = products
        return true
    }
}

// MainTableViewController, BaseTableViewController are subclasses of UITableViewController
class MainTableViewController: BaseTableViewController {
    var products = [Product]()

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return products.count
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier(BaseTableViewController.tableViewCellIdentifier, forIndexPath: indexPath)
        let product = products[indexPath.row]
        configureCell(cell, forProduct: product)
        return cell
    }
}

As AppDelegate implies, this table view controller has a navigation bar. And AppDelegate will successfully pass data to the table view controller. What if it doesn't? So I have the following.

class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        let products = [ ... ]

        let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let tableViewController = storyboard.instantiateViewController(withIdentifier: "tableController") as! MainTableViewController
        tableViewController.data = dataSet
        return true
    }
}

And the tableViewController never gets data from AppDelegate in a timely manner. I know how to change it so that the table view controller itself will get data from AppDelegate. But how can I make AppDelegate push data to the table view controller? Do I have to use the protocol for this process?

Thanks.

Answer 1

If your rootViewController is MainTableViewController instead of UINavigationController then type cast it to that particular ViewController and pass data to it.

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Product is a data model class.
    let products = [
        Product(hardwareType: Product.deviceTypeTitle, title: Product.Hardware.iPhone.rawValue, yearIntroduced: 2007, introPrice: 599.00),
        Product(hardwareType: Product.deviceTypeTitle, title: Product.Hardware.iPod.rawValue, yearIntroduced: 2001, introPrice: 399.00), ...
    ]

    if let tableViewController = window!.rootViewController as? MainTableViewController {
        tableViewController.products = products
    }
    return true
}

If your MainTableViewController is not rootViewController then you can use its shared instance within your MainTableViewController but for that you need to create instance property inside AppDelegate with type you want in your case it is [Product] .

AppDelegate

var products = Product

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Product is a data model class.
    self.products = [
        Product(hardwareType: Product.deviceTypeTitle, title: Product.Hardware.iPhone.rawValue, yearIntroduced: 2007, introPrice: 599.00),
        Product(hardwareType: Product.deviceTypeTitle, title: Product.Hardware.iPod.rawValue, yearIntroduced: 2001, introPrice: 399.00), ...
     ]

Now in MainTableViewController access that array like this.

if let delegate = UIApplication.sharedApplication().delegate as? AppDelegate {
    self.data = delegate.products
}