点击按钮将AddFoodViewController食材数组添加至ListViewController的TableView

Hey there! You're already doing great getting your ListViewController up and running as a new iOS dev. Let's work through getting that ingredient array from AddFoodViewController over to your shopping list. I'll walk you through two common, easy-to-implement solutions—starting with the one that fits best with your existing code.

Solution 1: Use Segues (Matches Your Current Setup) #

First, let's fix a couple of small issues in your code, then wire up the data transfer properly:

Step 1: Update ListViewController to Receive the Array #

Make sure your ListViewController has a variable that can hold the incoming array (your original code tried assigning an array to a String variable, which won't work!). Add this to ListViewController:

class ListViewController: UIViewController {
    // This will hold the ingredients sent from AddFoodVC
    var incomingFoodItems: [String] = []
    // Your existing code for the shopping list table view...
}

Step 2: Fix AddFoodViewController Code #

Let's clean up your AddFoodVC and add the logic to trigger the segue and pass the data:

class AddFoodViewController: UIViewController, UITableViewDataSource, UITableViewDelegate{
    @IBOutlet weak var FoodTableView: UITableView!
    @IBOutlet weak var sendFoodBtn: UIButton!
    // Your ingredient array
    let array = ["1 Salad", "3oz Chicken", "2 Tomatoes", "2 Cucumbers"]

    override func viewDidLoad() {
        super.viewDidLoad()
        // Don't forget to set the table view's data source/delegate!
        FoodTableView.dataSource = self
        FoodTableView.delegate = self
    }

    // Updated table view section count method (modern syntax)
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

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

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        // Use dequeueReusableCell instead of creating a new cell every time (better performance!)
        let foodCell = tableView.dequeueReusableCell(withIdentifier: "foodCell", for: indexPath)
        foodCell.textLabel?.text = array[indexPath.row]
        foodCell.backgroundColor = .clear
        foodCell.textLabel?.textColor = .darkGray
        foodCell.textLabel?.font = UIFont(name: foodCell.textLabel?.font.fontName ?? "System", size:17)
        return foodCell
    }

    // Trigger the segue when the "Add to List" button is tapped
    @IBAction func addOnClick(_ sender: Any) {
        performSegue(withIdentifier: "toList", sender: self)
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "toList" {
            // Safely cast the destination VC to ListViewController
            guard let listVC = segue.destination as? ListViewController else { return }
            // Pass your ingredient array to the ListVC's variable
            listVC.incomingFoodItems = array
        }
    }
}

Step 3: Use the Array in ListViewController #

Once the data is passed, add it to your shopping list and refresh the table view. Add this to ListViewController's viewDidLoad() (or wherever you handle updating the list):

override func viewDidLoad() {
    super.viewDidLoad()
    // Assume your shopping list array is called shoppingListArray
    shoppingListArray.append(contentsOf: incomingFoodItems)
    // Refresh the table view to show the new items
    tableView.reloadData()
}

Solution 2: Use a Closure (Great for Modal Presentations) #

If you're presenting AddFoodViewController modally (instead of pushing it via navigation), a closure is a more flexible approach that doesn't rely on segues:

Step 1: Add a Closure to AddFoodViewController #

Add a closure property that will "hand off" the array when the button is tapped:

class AddFoodViewController: UIViewController, UITableViewDataSource, UITableViewDelegate{
    // Closure to pass the food array back to ListVC
    var onFoodAdded: (([String]) -> Void)?

    // Your existing code...

    @IBAction func addOnClick(_ sender: Any) {
        // Pass the array through the closure
        onFoodAdded?(array)
        // Close the AddFoodVC
        dismiss(animated: true)
    }
}

Step 2: Set Up the Closure in ListViewController #

When you present AddFoodViewController from ListVC, set the closure to handle the incoming array:

// Example: Button action in ListVC to open AddFoodVC
@IBAction func openAddFoodVC(_ sender: Any) {
    guard let addFoodVC = storyboard?.instantiateViewController(withIdentifier: "AddFoodViewController") as? AddFoodViewController else { return }
    
    // Set the closure to receive the array
    addFoodVC.onFoodAdded = { [weak self] foodItems in
        // Add the new items to your shopping list
        self?.shoppingListArray.append(contentsOf: foodItems)
        // Refresh the table view
        self?.tableView.reloadData()
    }
    
    // Present the AddFoodVC modally
    present(addFoodVC, animated: true)
}

Quick Notes to Remember #

• Double-check that your segue identifier in Storyboard is exactly toList (case-sensitive!)
• Using dequeueReusableCell is a best practice—it reuses table view cells instead of creating new ones, which makes your app smoother
• When using closures, always use [weak self] to avoid memory leaks

内容的提问来源于stack exchange，提问作者Laura94