ios - 使用 Save 函数更新 ViewController 中的文本

Question

我很难弄清楚如何实现保存功能来更新 View Controller 中的文本。我一直在学习 Wenderlich 教程:https://www.raywenderlich.com/160519/storyboards-tutorial-ios-10-getting-started-part-2但这是针对 TableViewController 的，并使用 .append 将保存的项目添加到数组中，但我无法使用它，因为我使用的是简单的 View Controller 。我希望保存在 TableViewController 中的字符串显示在 View Controller 中。这就是我到目前为止所拥有的(saveGoal 函数位于底部)。我需要将什么添加到我的保存功能(或其他地方)？我对此很陌生，因此我们将不胜感激!

import UIKit

class LoLGoalViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

    }

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

}

extension LoLGoalViewController {

    @IBAction func cancelToLoLGoalViewController(_ segue: UIStoryboardSegue) {
    }

    @IBAction func saveGoal(_ segue: UIStoryboardSegue) {

        guard let addGoalsTableViewController = segue.source as? AddGoalsTableViewController,
            let goal = addGoalsTableViewController.goal else {
                return
        }

    }
}

这就是 addGoalViewController 的样子。我希望字符串 goalText 显示在 View Controller 中，其中显示“Lorem ipsum dolor goal”。

这是 addGoalsTableViewController 的代码，其中 goalText 由用户输入:

import UIKit

class AddGoalsTableViewController: UITableViewController {

    var goal:Goal?

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "SaveGoal" {
            let pointsNeededInt = Int(pointsNeededText.text!)
            let pointsEarnedInt = Int(goalProgressText.text!)
            goal = Goal(goalText: nameOfRewardText.text!, pointsToCompleteGoal: pointsNeededInt!, pointsEarnedTowardsGoal: pointsEarnedInt!)
        }
    }

    @IBOutlet var goalTableTitleText : UILabel!
    @IBOutlet weak var goalProgressText: UILabel!
    @IBOutlet weak var nameOfRewardText: UITextField!
    @IBOutlet weak var pointsNeededText: UITextField!
    @IBOutlet weak var repeatSwitch: UISwitch!


override func viewDidLoad() {
    super.viewDidLoad()

    }

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

这是 struct Goal 的代码:

import UIKit

struct Goal {
    var goalText: String
    var pointsToCompleteGoal: Int
    var pointsEarnedTowardsGoal: Int
    var repeatGoal: Bool

    init(goalText: String, pointsToCompleteGoal: Int, pointsEarnedTowardsGoal: Int, repeatGoal: Bool = false) {
        self.goalText = goalText
        self.pointsToCompleteGoal = pointsToCompleteGoal
        self.pointsEarnedTowardsGoal = pointsEarnedTowardsGoal
        self.repeatGoal = repeatGoal
    }
}

Answer 1

不要使用保存函数，而是使用带有委托(delegate)的协议(protocol)，如 @zombie 建议的那样。

1创建公共(public)协议(protocol):

protocol GoalDelegate: class {
    func passGoal(_ goal: Goal?)
}

2 在 AddGoalsTableViewController 中创建委托(delegate):

var delegate: GoalDelegate?

3当segue到LolGoalViewController时，在prepareForSegue方法中，将委托(delegate)设置为目的地，并调用协议(protocol)函数:

if let secondViewController = segue.destination as? LoLGoalViewController {
    delegate = secondViewController
    delegate?.passGoal(goal)
}

4在LoLGoalViewController中，遵守协议(protocol):

class LoLGoalViewController: UIViewController, GoalDelegate {

实现方法:

func passGoal(_ goal: Goal?) {
    //do whatever you need with the goal
}