tableview/tableviewcell labels.isHidden 的奇怪行为

Question

我有一个游戏，我想在其中显示表格视图中的历史记录。该游戏可以与 4 名玩家精确玩。 winners/losers 的结果可以在 2w/2l、3w/1l 或 1w/3l 之间变化。

因此我创建了一个自定义单元格作为 XIB，我在堆栈视图中放置了 3 个标签（每个标签用于赢家和输家，所以总共有 6 个标签），默认情况下我总是隐藏 2 个。然后，当我有多个 winner/loser 时，我将取消隐藏它们并设置名称。

但是我的代码以某种方式做了一些我不理解的事情。我试图调试我的代码，但如果它运行缓慢，似乎没问题。没看懂。

我的 Players 结构只是我的 Realm 对象的一小部分。此外，整个 allPlayers 数组只是虚拟数据，通常我从领域获取它。

struct Players {
    let round: Int
    let name: String
    let winner: Bool
    let loser: Bool
}

所以我的 ViewController 标准设置如下：

class ViewController: UIViewController {

    @IBOutlet weak var tableView: UITableView!
    
    let allPlayers: [Players] = [Players(round: 1, name: "Mike", winner: false, loser: true),     // Round 1 2:2
                                 Players(round: 1, name: "Peter", winner: false, loser: true),
                                 Players(round: 1, name: "Tim", winner: true, loser: false),
                                 Players(round: 1, name: "Levi", winner: true, loser: false),
                                 Players(round: 2, name: "Mike", winner: false, loser: true),     // Round 2 1:3
                                 Players(round: 2, name: "Peter", winner: false, loser: true),
                                 Players(round: 2, name: "Tim", winner: false, loser: true),
                                 Players(round: 2, name: "Levi", winner: true, loser: false),
                                 Players(round: 3, name: "Mike", winner: true, loser: false),     // Round 3 3:1
                                 Players(round: 3, name: "Peter", winner: true, loser: false),
                                 Players(round: 3, name: "Tim", winner: true, loser: false),
                                 Players(round: 3, name: "Levi", winner: false, loser: true),
                                 Players(round: 4, name: "Mike", winner: false, loser: true),     // Round 4 2:2
                                 Players(round: 4, name: "Peter", winner: false, loser: true),
                                 Players(round: 4, name: "Tim", winner: true, loser: false),
                                 Players(round: 4, name: "Levi", winner: true, loser: false),
                                 Players(round: 5, name: "Mike", winner: false, loser: true),     // Round 5 1:3
                                 Players(round: 5, name: "Peter", winner: false, loser: true),
                                 Players(round: 5, name: "Tim", winner: false, loser: true),
                                 Players(round: 5, name: "Levi", winner: true, loser: false),
                                 Players(round: 6, name: "Mike", winner: true, loser: false),     // Round 6 3:1
                                 Players(round: 6, name: "Peter", winner: true, loser: false),
                                 Players(round: 6, name: "Tim", winner: true, loser: false),
                                 Players(round: 6, name: "Levi", winner: false, loser: true),
                                 Players(round: 7, name: "Mike", winner: true, loser: false),     // Round 7 3:1
                                 Players(round: 7, name: "Peter", winner: true, loser: false),
                                 Players(round: 7, name: "Tim", winner: true, loser: false),
                                 Players(round: 7, name: "Levi", winner: false, loser: true),
                                 Players(round: 8, name: "Mike", winner: false, loser: true),     // Round 8 1:3
                                 Players(round: 8, name: "Peter", winner: false, loser: true),
                                 Players(round: 8, name: "Tim", winner: false, loser: true),
                                 Players(round: 8, name: "Levi", winner: true, loser: false),
                                 Players(round: 9, name: "Mike", winner: false, loser: true),     // Round 9 1:3
                                 Players(round: 9, name: "Peter", winner: false, loser: true),
                                 Players(round: 9, name: "Tim", winner: false, loser: true),
                                 Players(round: 9, name: "Levi", winner: true, loser: false),
                                 Players(round: 10, name: "Mike", winner: false, loser: true),     // Round 10 2:2
                                 Players(round: 10, name: "Peter", winner: false, loser: true),
                                 Players(round: 10, name: "Tim", winner: true, loser: false),
                                 Players(round: 10, name: "Levi", winner: true, loser: false),
                                 Players(round: 11, name: "Mike", winner: false, loser: true),     // Round 11 2:2
                                 Players(round: 11, name: "Peter", winner: false, loser: true),
                                 Players(round: 11, name: "Tim", winner: true, loser: false),
                                 Players(round: 11, name: "Levi", winner: true, loser: false),
                                 Players(round: 12, name: "Mike", winner: true, loser: false),     // Round 12 3:1
                                 Players(round: 12, name: "Peter", winner: true, loser: false),
                                 Players(round: 12, name: "Tim", winner: true, loser: false),
                                 Players(round: 12, name: "Levi", winner: false, loser: true)]
    
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.dataSource = self
        let nib = UINib.init(nibName: "TableViewCell", bundle: nil)
        self.tableView.register(nib, forCellReuseIdentifier: "winLooseCell")
    }
}

因为我从 Realm 获取数据，所以我做了一个单独的 class handler 来管理结果，所以我只取回 winners/losers.[=23 的名称数组=]

class Handler {
    var winners: [String] = []
    var losers: [String] = []
    
    func getWinners(round: Int,dataBase: [Players]) -> [String] {
        // Filtercode is just boilerplate, is dunno by realm
        let filtered = dataBase.filter{ dataBase in
            return dataBase.round == round
        }
        for i in 0...filtered.count - 1 {
            if filtered[i].winner {
                winners.append(filtered[i].name)
            }
        }
        return winners
    }
    
    func getLosers(round: Int,dataBase: [Players]) -> [String] {
        // Filtercode is just boilerplate, is dunno by realm
        let filtered = dataBase.filter{ dataBase in
            return dataBase.round == round
        }
        for i in 0...filtered.count - 1{
            if filtered[i].loser {
                losers.append(filtered[i].name)
            }
        }
        return losers
    }
}

当然还有我的 tableView 扩展来创建整个东西

// MARK: Extension
extension ViewController: UITableViewDelegate, UITableViewDataSource {
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return (allPlayers.count / 4)
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let handler = Handler()
        
        if indexPath.row == 10 {
            // do nothing - just for a debugging breakpoint
        }
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "winLooseCell") as! TableViewCell
        
        let winner = handler.getWinners(round: indexPath.row + 1, dataBase: allPlayers)
        for i in 0...winner.count - 1 {
            cell.winnerNameLabels[i].isHidden = false
            cell.winnerNameLabels[i].text = winner[i]
        }
        
        let loser = handler.getLosers(round: indexPath.row + 1, dataBase: allPlayers)
        for i in 0...loser.count - 1 {
            cell.loserNameLabels[i].isHidden = false
            cell.loserNameLabels[i].text = loser[i]
        }
        
        cell.roundLabel.text = "\(indexPath.row + 1)"
        
        return cell
    }
}

tableViewCellclass

class TableViewCell: UITableViewCell {
    @IBOutlet var winnerNameLabels: [UILabel]!
    @IBOutlet var loserNameLabels: [UILabel]!
    @IBOutlet weak var roundLabel: UILabel!
}

和 Xib 文件

出于某种原因，在我加载模拟器后，我在第 11 轮遇到了这种奇怪的行为

有人知道为什么以及如何解决这个问题吗？

Answer 1

您忘记了细胞是重复使用的。出现在特定行中的单元格稍后可以重新出现在不同的行中——例如，当您滚动时。因此，您必须在配置单元格的逻辑中完全考虑这是哪一行。

因此，在 cellForRowAt 中，我们看到您的代码可能会说

 cell.winnerNameLabels[i].isHidden = false

但是在没有的时候你曾经说

 cell.winnerNameLabels[i].isHidden = true

因此，一旦您取消隐藏该单元格的标签，它将保持不隐藏状态，无论该单元格在哪一行中重复使用，在应用程序的剩余生命周期内。

tableview/tableviewcell labels.isHidden 的奇怪行为

tableview/tableviewcell weird behavior with labels.isHidden

realm

uitableview

swift