ios - 使用未解析的标识符 "performSegue"错误

Question

为什么 Xcode 告诉我 performSegue(withIdentifier:) 是一个未解析的标识符？ (请参阅注释掉的行)

import UIKit

class AllListsViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem()
    }

    // MARK: - Table view data source

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = makeCell(for: tableView)
        cell.textLabel!.text = "List \(indexPath.row)"

        return cell
    }
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    performSegue(withIdentifier: "ShowChecklist", sender: nil) // Use of unresolved identifier "performSegue"
}

func makeCell(for tableView: UITableView) -> UITableViewCell {
    let cellIdentifier = "Cell"
    if let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) {
        return cell
    } else {
        return UITableViewCell(style: .default, reuseIdentifier: cellIdentifier)
    }
}

Answer 1

您的代码中有两个错误:

1. 第 27 行 应在最后，因为这将结束类(class)
2. 您继承自 UITableViewController，因此您需要覆盖 tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)<

编译代码:

import UIKit

class AllListsViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem()
    }

    // MARK: - Table view data source

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = makeCell(for: tableView)
        cell.textLabel!.text = "List \(indexPath.row)"

        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        performSegue(withIdentifier: "ShowChecklist", sender: nil) // Use of unresolved identifier "performSegue"
    }

    func makeCell(for tableView: UITableView) -> UITableViewCell {
        let cellIdentifier = "Cell"
        if let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) {
            return cell
        } else {
            return UITableViewCell(style: .default, reuseIdentifier: cellIdentifier)
        }
    }
}