如何使用NSKeyedArchiver保存数据？

Question

我非常接近使用Swift 4和iOS 11完成我的第一个iOS应用程序。

该应用程序在表视图控制器中显示一个列表，并且具有可编辑的UITextView对象的详细视图。我的目标是让用户能够对UITextView中的内容进行编辑，并使用NSKeyedArchiver保存这些更改。

我已完成列表视图并连接了详细视图。您可以进行编辑但不保存。

我已经确认该条目会保存到会话之外的内存，但编辑不会保存。

对文档进行审核并通过多个教程进行操作并未提供所需的见解。我附加了一个屏幕截图来显示详细视图的界面，这里是详细视图控制器中的代码，其中保存按钮触发了保存操作：

pub struct Cmd<K, E> {
    cmds: Vec<Cmd<K, E>>,
}

impl<K, E> Cmd<K, E> {
    pub fn invoke(&mut self, cmd_name: &str) -> Result<K, E> {
        let cmd_to_invoke = self.cmds.iter_mut().find(|cmd| cmd.name == cmd_name);
        if let Some(cmd) = cmd_to_invoke {
            cmd.invoke()
        } else {
            // Some default / placeholder value for E
            Err(/* ? */)
        }
    }
}

以下是数据模型类的代码：

import UIKit
import os.log

class ViewController: UIViewController, UINavigationControllerDelegate, UITextViewDelegate  {

  var season: Season?

  //MARK: Properties

  @IBOutlet weak var seasonDetail: UITextView!
  @IBAction func saveButton(_ sender: UIBarButtonItem) {
    if let selectedDetail = seasonDetail.text {
      seasonDetail.text = selectedDetail
    } else {
      print("failed to save changes.")
    }
    saveChanges()
    print("Save button clicked")
  }

  override func viewDidLoad() {
    super.viewDidLoad()

      title = season?.name
      seasonDetail.text = season?.detail
    seasonDetail.delegate=self
  }

  override func viewWillDisappear(_ animated: Bool) {
    season?.detail = (seasonDetail?.text)!
  }

  func textViewDidEndEditing(_ textView: UITextView) {
    seasonDetail.text = season?.detail
  }

  //MARK: UITextViewdDelegate

  func textViewShouldReturn(_ textView: UITextView) -> Bool {
    textView.resignFirstResponder()

    return true
  }


 func saveChanges() {
    print("Saving items to: \(Season.ArchiveURL)")
    let isSuccessfulSave = NSKeyedArchiver.archiveRootObject(season as Any, toFile: Season.ArchiveURL.path)

    if isSuccessfulSave {
      os_log("Season sucessfully saved.", log: OSLog.default, type: .debug)
    } else {
      os_log("Failed to save season.", log: OSLog.default, type: .debug)
    }
  }

}

我的目标是了解我的代码缺少什么，并知道如何保留所有数据，包括编辑。我会很感激任何有用的方向。

Answer 1

请检查：

class ViewController: UIViewController, UINavigationControllerDelegate, UITextViewDelegate  {
    var season: Season?
    @IBOutlet weak var seasonDetail: UITextView!
    @IBAction func saveButton(_ sender: UIBarButtonItem) {
        if let selectedDetail = seasonDetail.text {
            season?.detail = selectedDetail // this is the line
        } else {
            print("failed to save changes.")
        }
        saveChanges()
        print("Save button clicked")
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        if season == nil {
            season = Season(name: "Season Name", detail: "Season Details")
        }
        title = season?.name
        seasonDetail.text = season?.detail
        seasonDetail.delegate=self
    }

    override func viewWillDisappear(_ animated: Bool) {
        season?.detail = (seasonDetail?.text)!
    }

    func textViewDidEndEditing(_ textView: UITextView) {
         season?.detail = seasonDetail.text
    }

    //MARK: UITextViewdDelegate
    func textViewShouldReturn(_ textView: UITextView) -> Bool {
        textView.resignFirstResponder()
        return true
    }

    func saveChanges() {
        print("Saving items to: \(Season.ArchiveURL)")
        let isSuccessfulSave = NSKeyedArchiver.archiveRootObject(season as Any, toFile: Season.ArchiveURL.path)

        if isSuccessfulSave {
            os_log("Season sucessfully saved.", log: OSLog.default, type: .debug)
        } else {
            os_log("Failed to save season.", log: OSLog.default, type: .debug)
        }
    }
}