将选定行的索引传递给另一个 ViewController

编程问答 2022-05-27

问题描述

我有一个关于将索引 (myIndex) 从 TableView 传递到另一个 ViewController 的问题。 我已经在下面发布了代码。好消息：当我运行代码时，一个索引被传递给另一个视图控制器。坏消息：它不是我预期的指数。 （当我使用 TableView 在 ViewController 中打印出 myindex 时，一切正常。如果我将 myIndex 传递给另一个 ViewController，则索引会混淆...

目标：我的 TableView 包含 18 行（每个孔一行）。当我单击一行时，将打开另一个 Viewcontroller。在此 VieController 中，所选行的名称应显示在顶部。 我的想法是将每一行的索引传递给另一个 Viewcontroller，但这无法正常工作。

有人可以帮我吗？

#include <mysqlx/xdevapi.h>
#include <iostream>
using namespace mysqlx;

int main() {
    try {
        Session sess(33060,"user","password");
    }
    catch (const Error & err) {
        std::cout << err << std::endl;
        exit(1);
    }

    return 0;
}

和 ScoreViewController：

import UIKit
var holes = ["Hole 1","Hole 2","Hole 3","Hole 4","Hole 5","Hole 6","Hole 7","Hole 8","Hole 9","Hole 10","Hole 11","Hole 12","Hole 13","Hole 14","Hole 15","Hole 16","Hole 17","Hole 18"]
var myIndex = 0

class OverViewController: UIViewController,UITableViewDataSource,UITableViewDelegate {
    
    // Label
    @IBOutlet weak var BackButton: UIButton!
    @IBOutlet weak var ScoreButton: UIButton!
    @IBOutlet weak var OverviewLabel: UILabel!
    

    @IBOutlet weak var tableView: UITableView!
    

    override func viewDidLoad() {
           super.viewDidLoad()
    }
    
    
    @IBAction func BackToStartScreen(_ sender: UIButton) {
        performSegue(withIdentifier: "BackToStart",sender: self)
    }
    
    @IBAction func GoToResultScreen(_ sender: UIButton) {
        performSegue(withIdentifier: "GoToResult",sender: self)
    }
    
        
    func tableView(_ tableView: UITableView,numberOfRowsInSection section: Int) -> Int {
            return holes.count
    }
        
    func tableView(_ tableView: UITableView,cellForRowAt indexPath: IndexPath) -> UITableViewCell {
            let cell = tableView.dequeueReusableCell(withIdentifier: "cell",for: indexPath)
            cell.textLabel?.text = holes[indexPath.row]
            return cell
    }
    
    func tableView(_ tableView: UITableView,didSelectRowAt indexPath: IndexPath) {
        myIndex = indexPath.row
        performSegue(withIdentifier: "GoToScore",sender: self)
        
    }
  
}

和结果视图控制器：

import UIKit



class ScoreViewController: UIViewController {
    var score = 0
    var fairwayhits = 0
    var greeninregulation = 0
    var putts = 0
    var text = ""
        
    // Variable Deklaration
    var CurrentScore = 0
    var CurrentFairwayHits = 0
    var CurrentGreenInRegulations = 0
    var CurrentPutts = 0

    
    
    // Bar Label
    @IBOutlet weak var BackLabel: UIButton!
    @IBOutlet weak var TitleLabel: UILabel!
    
    // Score Elements
    @IBOutlet var ScoreLabel: UILabel!
    @IBOutlet var ScoreStepper: UIStepper!
    @IBOutlet var ScoreResultLabel: UILabel!
    @IBOutlet var ScoreFrameLabel: UILabel!
    
    // Fairway Elements
    @IBOutlet var FairwayLabel: UILabel!
    @IBOutlet var FairwaySwitch: UISwitch!
    @IBOutlet var FairwayResultLabel: UILabel!
    @IBOutlet var FairwayFrameLabel: UILabel!
    
    // Green Elements
    @IBOutlet var GreenLabel: UILabel!
    @IBOutlet var GreenSwitch: UISwitch!
    @IBOutlet var GreenResultLabel: UILabel!
    @IBOutlet var GreenFrameLabel: UILabel!
    
    // Putt Elements
    @IBOutlet var PuttLabel: UILabel!
    @IBOutlet var PuttStepper: UIStepper!
    @IBOutlet var PuttResultLabel: UILabel!
    @IBOutlet var PuttFrameLabel: UILabel!
    
    // Save Button
    @IBOutlet var SaveButton: UIButton!
    
    // Back Button
    @IBAction func BackButtonPressed(_ sender: UIButton) {
        performSegue(withIdentifier: "BackToOverview",sender: self)
    }
    
    // Score Stepper
    @IBAction func ScoreStepperPressed(_ sender: UIStepper) {
        ScoreResultLabel.text = Int(sender.value).description
    }
    
    // Fairway Switch
    @IBAction func FairwaySwitchPressed(_ sender: UISwitch) {
        if FairwaySwitch.isOn {
            CurrentFairwayHits = 1
            FairwayResultLabel.text = "X"
        } else {
            CurrentFairwayHits = 0
            FairwayResultLabel.text = "-"
        }
    }
    
    // Green Switch
    @IBAction func GreenSwitchPressed(_ sender: UISwitch) {
        if GreenSwitch.isOn {
            CurrentGreenInRegulations = 1
            GreenResultLabel.text = "X"
        } else {
            CurrentGreenInRegulations = 0
            GreenResultLabel.text = "-"
        }
    }
    

    // Putt Stepper
    @IBAction func PuttStepperPressed(_ sender: UIStepper) {
        PuttResultLabel.text = Int(sender.value).description
    }
    
    
    // Save Button
    @IBAction func SaveButtonPressed(_ sender: UIButton) {
        if Int(PuttResultLabel.text!)! >= Int(ScoreResultLabel.text!)! {
            showAlert()
        } else {
        score = score + Int(ScoreResultLabel.text!)!
        fairwayhits = fairwayhits + CurrentFairwayHits
        greeninregulation = greeninregulation + CurrentGreenInRegulations
        putts = putts + Int(PuttResultLabel.text!)!
        
        print(score)
        print(fairwayhits)
        print(greeninregulation)
        print(putts)
            
        performSegue(withIdentifier: "ShowResult",sender: self)
        }
    }
    
    
    func showAlert() {
        let alert = UIAlertController(title: "Ops,something went wrong",message: "The number of putts must be smaller than your score!",preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "Ok",style: .cancel,handler: { action in print("tapped Dismissed")}))
        
        present(alert,animated: true)
    }

    
    override func prepare(for segue: UIStoryboardSegue,sender: Any?) {
        if SaveButton.isTouchInside,let resultVC = segue.destination as? ResultViewController
            {

            CurrentScore = score /// get the current cell's text
            CurrentPutts = putts
            resultVC.score = resultVC.score + String((resultVC.ScoreResultLabel.text!))
            resultVC.fairway = String(fairwayhits)
            resultVC.green = String(greeninregulation)
            resultVC.putt = String(putts)
            
            
               }
    }
    
    

    override func viewDidLoad() {
        
        super.viewDidLoad()

        ScoreStepper.wraps = true
        ScoreStepper.autorepeat = true
        ScoreStepper.minimumValue = 1
        ScoreStepper.maximumValue = 20
        
        PuttStepper.wraps = true
        PuttStepper.autorepeat = true
        PuttStepper.minimumValue = 0
        PuttStepper.maximumValue = 20
        

        TitleLabel.text = text
    
    }
}

解决方法

第一件事：你不想在类之外有变量。当然，您可以从所有课程中访问它们。但是，这不是一个好习惯，你会遇到状态错误。

所以，替换

var holes = ["Hole 1","Hole 2","Hole 3","Hole 4","Hole 5","Hole 6","Hole 7","Hole 8","Hole 9","Hole 10","Hole 11","Hole 12","Hole 13","Hole 14","Hole 15","Hole 16","Hole 17","Hole 18"]
var myIndex = 0

class OverViewController: UIViewController,UITableViewDataSource,UITableViewDelegate {

与

class OverViewController: UIViewController,UITableViewDelegate {
    var holes = ["Hole 1","Hole 18"]
    var myIndex = 0

也替换

var score = 0
var fairwayhits = 0
var greeninregulation = 0
var putts = 0

var text = ""

class ScoreViewController: UIViewController {

与

class ScoreViewController: UIViewController {
    var score = 0
    var fairwayhits = 0
    var greeninregulation = 0
    var putts = 0

    var text = ""

现在，我假设您想要这种行为：

  1. 按下表格视图上的一个单元格
  2. Present ScoreViewController 显示单元格的文本

你可以把它放在你的 prepareForSegue 函数中：

override func prepare(for segue: UIStoryboardSegue,sender: Any?) {
    guard let selectedPath = tableView.indexPathForSelectedRow else { return }
    if 
        segue.identifier == "GoToScore",let scoreVC = segue.destination as? ScoreViewController
    {
        let currentText = holes[selectedPath.row] /// get the current cell's text
        scoreVC.text = currentText
    }
}

编辑：然后您可以将 TitleLabel.text 设置为 text 内的 viewDidLoad 属性，如下所示：

class ScoreViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        TitleLabel.text = text /// right here!
    }   
}

您还应该保持所有属性，包括像 TitleLabel 这样的出口，小写。这只是一个约定，让其他人更容易阅读您的代码。

@IBOutlet weak var backLabel: UIButton!
@IBOutlet weak var titleLabel: UILabel!

请记住，要更改插座的名称，您需要断开链接并从故事板重新链接。

indexpathswiftswiftswiftxcodexcode

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