Question

所以，这里是新功能，学习Swift 5.1，我正在研究一个简单的待办事项清单。除了UITextFieldDelegate之外，其他所有东西都在工作。这是我的代码：

import UIKit
import CoreData

class ViewController: UIViewController, UITextFieldDelegate, UITableViewDelegate, UITextFieldDelegate {



@IBOutlet weak var table: UITableView!
var itemName: [NSManagedObject] = []


override func viewDidLoad() {
    super .viewDidLoad()
    // Do any additional setup after loading the view.
}


override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
}

override func didReceiveMemoryWarning() {
     super.didReceiveMemoryWarning()
}

var titleTextField: UITextField!
func titleTextField(textfield: UITextField) {

    titleTextField = textfield
    titleTextField.placeholder = "Item Name"
}


@IBAction func addButton(_ sender: Any) {

    let alert = UIAlertController(title: "Add Item", message: "Item Name", preferredStyle: .alert)
    let addAction = UIAlertAction(title: "Save", style: .default, handler: self.save)
    let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)

    alert.addAction(addAction)
    alert.addAction(cancelAction)
    alert.addTextField(configurationHandler: titleTextField)

    self.present(alert, animated: true, completion: nil)

}


func save(alert: UIAlertAction!) {

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext
    let entity =
        NSEntityDescription.entity(forEntityName: "Title", in: context)!
    let theTitle = NSManagedObject(entity: entity, insertInto: context)
    theTitle.setValue(titleTextField.text, forKey: "title")

    do
    {
        try context.save()
        itemName.append(theTitle)


    }

    catch{
        print("There was an error saving")
    }


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


    func tableView(_ tableView:UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let title = itemName[indexPath.row]
    let cell =
        tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        cell.textLabel?.text = title.value(forKey: "Title") as? String
    return cell

}

在第4行（ViewController类）中，出现此错误：

“'ViewController'与协议'UITextFieldDelegate的冗余一致性”

我连接了2个导航控制器。

Answer 1

您两次符合UITextFieldDelegate，应该是

class ViewController: UIViewController, UITableViewDelegate, UITextFieldDelegate {

对于表视图也不要忘记UITableViewDataSource

“'ViewController'与协议'UITextFieldDelegate的冗余一致性”

1 个答案: