ios - 我有一个仅当我的 UITableView 为空时才可见的 UILabel。如何在 Swift 中将该标签的文本居中？

Question

我的应用程序中有一个 UITableView，我想在没有内容时在那里显示一个 UILabel。到目前为止我正在做的:

@IBOutlet var tview: UITableView!

var emptyLabel = UILabel(frame: CGRectMake(0, 10, 100, 100))

override func viewDidLoad(){

    let refreshControl = UIRefreshControl()

    refreshControl.addTarget(self, action: "refresh:", forControlEvents: .ValueChanged)
    refreshControl.attributedTitle = NSAttributedString(string: "last updated on \(NSDate())")

    tview.separatorStyle = UITableViewCellSeparatorStyle.None
    tview.addSubview(refreshControl)


    emptyLabel.numberOfLines = 0
    emptyLabel.text = "There is no content in this table for now. Please pull down the list to refresh and something should appear"
    emptyLabel.font = emptyLabel.font.fontWithSize(10)
    tview.backgroundView = emptyLabel
}

但是当我这样做时，我得到以下结果:

而不是向左对齐，我想将文本居中，这样它看起来像:

       There is no content in this table for now. Please pull down the
                list to refresh and something should appear

此外，目前它是垂直居中的 - 有没有办法将这条消息放在屏幕顶部的 1/3 处？

====== 编辑

@Md.Muzahidul Islam 这是我在空 table 时展示标签的方式:

override func tableView(tview: UITableView, numberOfRowsInSection section: Int) -> Int {

    if self.items.count == 0{
        self.emptyLabel.hidden = false
        return 0
    } else {
        self.emptyLabel.hidden = true
    return self.items.count;
    }
}

Answer 1

您可以通过以下方式实现:

override func viewDidLoad()
{
   // Other codes
   emptyLabel               = UILabel(frame: CGRectMake(0, 0, tview.bounds.size.width, view.bounds.size.height))
   emptyLabel.textAlignment = NSTextAlignment.Center
   emptyLabel.numberOfLines = 0
   emptyLabel.text          = "There is no content in this table for now. Please pull down the list to refresh and something should appear"
   emptyLabel.font          = emptyLabel.font.fontWithSize(10)
   tview.backgroundView     = emptyLabel
}

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