グループ化されたテーブルビューはnilを送信しますが、プレーンは完全に動作します

Question

テーブルをグループ化してnilを送信すると問題が発生しますが、すべてを1の配列として保持しても何の問題もなく、ここでは、nilを送信するグループ化されたテーブルビューのコードを示します。これは簡単な修正だと思います。おかげ

のViewController：

import UIKit 

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate { 

    @IBOutlet weak var tableView: UITableView! 

    var runeTitle = [["Freyr/Freya's Aett"], ["Heimdall's Aett"], ["Tyr's Aett"], ["Additional Runes"]] 

    let runes = [[Rune(runeName: "Fehu", runeImage: UIImage(named: ("Fehu.png"))!, runeDescription: "(F: Domestic cattle, wealth.) Possessions won or earned, earned income, luck. Abundance, financial strength in the present or near future. Sign of hope and plenty, success and happiness. Social success. Energy, foresight, fertility, creation/destruction (becoming).\n\n Fehu Reversed or Merkstave: Loss of personal property, esteem, or something that you put in effort to keep. It indicates some sort of failure. Greed, burnout, atrophy, discord. Cowardice, stupidity, dullness, poverty, slavery, bondage.")], 

       [Rune(runeName: "Hagalaz", runeImage: UIImage(named: ("Hagalaz.png"))!, runeDescription: "(H: Hail.) Wrath of nature, destructive, uncontrolled forces, especially the weather, or within the unconscious. Tempering, testing, trial. Controlled crisis, leading to completion, inner harmony. Hagalaz Merkstave (Hagalaz cannot be reversed, but may lie in opposition): Natural disaster, catastrophe. Stagnation, loss of power. Pain, loss, suffering, hardship, sickness, crisis.")], 

        [Rune(runeName: "Blank Rune", runeImage: UIImage(named: ("Blank.png"))!, runeDescription: "There is no historical support for a \"Blank Rune\" in runic divination. It was invented in the 1980's. It should not be used in a rune casting. If you bought a rune set with a blank piece, save it in case you lose another rune piece, but don't use it in rune casting.")]] 

    func numberOfSections(in tableView: UITableView) -> Int { 
     // #warning Incomplete implementation, return the number of sections 
     return runes.count 
    } 

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 
     // #warning Incomplete implementation, return the number of rows 
     return runes[section].count 
    } 

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { 

     // Configure the cell... 

     let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as UITableViewCell; 

     let item = runes[indexPath.section][indexPath.row] 
     cell.imageView?.image = item.runeImage 
     cell.textLabel?.text = item.runeName 
     cell.accessoryType = UITableViewCellAccessoryType.disclosureIndicator 

     return cell 
    } 

    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? { 

     return String(describing: runeTitle[section][0]) 
    } 

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) { 
     if segue.identifier == "segue" { 

      let rune = sender as! Rune 
      let destinationVC = segue.destination as! SecondViewController 
      destinationVC.selectedRune = rune 
     } 
    } 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     // Do any additional setup after loading the view, typically from a nib. 

    } 

} 

SecondViewController：

import UIKit 

class SecondViewController: UIViewController { 

    var selectedRune: Rune! 

    @IBOutlet weak var runeNameLabel: UILabel! 
    @IBOutlet weak var runeImage: UIImageView! 
    @IBOutlet weak var runeDescriptionLabel: UILabel! 

    override func viewDidLoad() { 
     super.viewDidLoad() 

     // Do any additional setup after loading the view. 

     runeNameLabel.text = selectedRune.runeName 
     runeImage.image = selectedRune.runeImage 
     runeDescriptionLabel.text = selectedRune.runeDescription 
    } 

} 

Answer 1

あなたはsenderprepareForSegue内の関数を使用して回避しようとすることができます。代わりに、アイテムのインデックスを変数として保存し、そこから読み取ります。送信者は何にでもキャストすることができるので、将来あなたのプロジェクトを維持することは難しくなります。

ですから、このような何かを探しています：

var clickedIndex = 0 

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { 
    self.clickedIndex = indexPath.row 
} 

override func prepare(for segue: UIStoryboardSegue, sender: Any?) { 
    if segue.identifier == "segue" { 

     let runeArray = runes[clickedIndex]// variable runeArray is the child array from runes 
     let destinationVC = segue.destination as! SecondViewController 
     destinationVC.selectedRune = runeArray[0]// Now choose an actual Rune object from the array by index 
    } 
}