swift - xcode Playground 中的 UITableView 不显示文本/字幕

Question

我正在关注一篇有关 WWDC17 的文章。一切都很好，但我的实时 View 看起来并不像应有的那样。 (.subtitle) 和表格单元格未显示任何内容

有人可以帮助我如何完成这项工作吗？

以下是 Playground :

import PlaygroundSupport
import UIKit

class WWDCMasterViewController: UITableViewController {

    var reasons = ["WWDC is great", "the people are awesome", "I love lab works", "key of success"]

    override func viewDidLoad() {
        title = "Reason I should attend WWDC18"
        view.backgroundColor = .lightGray
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        var cell: UITableViewCell!
        cell = tableView.dequeueReusableCell(withIdentifier: "Cell")
        if cell == nil {
            cell = UITableViewCell(style: .subtitle , reuseIdentifier: "Cell")
            cell.accessoryType = .disclosureIndicator
        }

        let reason = reasons[indexPath.row]
        cell.detailTextLabel?.text = "I want to attend because\(reason)"
        cell.textLabel?.text = "Reason #\(indexPath.row + 1)"

        return cell
    }
}

let master = WWDCMasterViewController()
let nav = UINavigationController(rootViewController: master)
PlaygroundPage.current.liveView = nav

Answer 1

由于您缺少 UITableViewDataSource 的方法 numberOfRowsInSection，因此您的 UITableView 最终只有 0 行，请尝试添加以下内容:

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return self.reasons.count
}

这是固定的 Playground :

import PlaygroundSupport
import UIKit

class WWDCMasterViewController: UITableViewController {

    var reasons = ["WWDC is great", "the people are awesome", "I love lab works", "key of success"]

    override func viewDidLoad() {
        title = "Reason I should attend WWDC18"
        view.backgroundColor = .lightGray
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.reasons.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        var cell: UITableViewCell! = tableView.dequeueReusableCell(withIdentifier: "Cell")
        if cell == nil {
            cell = UITableViewCell(style: .subtitle , reuseIdentifier: "Cell")
            cell.accessoryType = .disclosureIndicator
        }

        let reason = reasons[indexPath.row]
        cell.detailTextLabel?.text = "I want to attend because\(reason)"
        cell.textLabel?.text = "Reason #\(indexPath.row + 1)"

        return cell
    }
}

let master = WWDCMasterViewController()
let nav = UINavigationController(rootViewController: master)
PlaygroundPage.current.liveView = nav