swift - detailTextLabel 不会在 ios 8 swift 中更新

Question

我有一个简单的表格 View ，它使用 UITableViewController 和 Subtitle 样式。我无法成功更新detailTextView 字段。我在 Stack Overflow 上读到，ios 8 中存在潜在的错误，但所有建议的解决方法都不适合我。当我打印该字段的值时，我得到零。任何帮助，将不胜感激。下面是下面的代码，后面是 println 语句的结果。我看到另一个 SO 条目列出了 ios 8 中的一个错误，但建议的解决方法都不适合我。我也在苹果论坛上提出了这个问题

import UIKit

class TableViewController: UITableViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    self.navigationItem.title = "Test"
    self.navigationItem.rightBarButtonItem = self.editButtonItem()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

// MARK: - Table view data source

override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    return 1
}

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


override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")
    let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as!UITableViewCell
    let xrow = indexPath.row
    let xsection = indexPath.section
    //if (xrow == 0) && (xsection == 0)  {
        // initializing with hard values initially
        cell.textLabel?.text = "initial"
        cell.detailTextLabel?.text = "Initial"
    //}

    println("row = \(xrow), section = \(xsection)")
    println("0: cell.textLabel?.text = \(cell.textLabel?.text)")
    cell.textLabel?.text = "Section = \(xsection)"
    println("1: cell.textLabel?.text = \(cell.textLabel?.text)")
    println("0: cell.detailTextLabel?.text = \(cell.detailTextLabel?.text)")
    cell.detailTextLabel?.text = ("section = \(xsection), row = \(xrow)") as String!
    println("1: cell.detailTextLabel?.text = \(cell.detailTextLabel?.text)")
    return cell
}

}


row = 0, section = 0
0: cell.textLabel?.text = Optional("initial")
1: cell.textLabel?.text = Optional("Section = 0")
0: cell.detailTextLabel?.text = nil
1: cell.detailTextLabel?.text = nil
row = 1, section = 0
0: cell.textLabel?.text = Optional("initial")
1: cell.textLabel?.text = Optional("Section = 0")
0: cell.detailTextLabel?.text = nil
1: cell.detailTextLabel?.text = nil
row = 2, section = 0
0: cell.textLabel?.text = Optional("initial")
1: cell.textLabel?.text = Optional("Section = 0")
0: cell.detailTextLabel?.text = nil
1: cell.detailTextLabel?.text = nil

Answer 1

因为如果单元格样式不支持，detailTextLabel 总是返回 nil。

UITableViewCell detailTextLabel reference

所以改变

tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as!UITableViewCell

到

var cell = tableView.dequeueReusableCellWithIdentifier("CellIdentifier") as? UITableViewCell
if cell == nil{
    cell = UITableViewCell(style: .Subtitle, reuseIdentifier: "CellIdentifier")
}