意外地在 prepareForSegue 中发现了 nil IBOutlet [英] Unexpectedly found nil IBOutlet in prepareForSegue

问题描述

我有一个详细信息视图控制器，我想将标签文本设置为使用 indexPath 行从数组中获取的值.

I have a detail view controller, and I would like to set the label text to a value taken from an array using an indexPath row.

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if(segue.identifier == "showView"){
        let detailVC: DetailViewController = segue.destinationViewController as! DetailViewController
        let indexPath = self.MainTableView.indexPathForSelectedRow!
        detailVC.label.text = "Test"
        self.MainTableView.deselectRowAtIndexPath(indexPath, animated: true)
        }
}

我不断收到致命错误:在解开可选值时意外发现 nil.我尝试将 detailVC.label.text = "Test" 切换为 detailVC.label.text = names[indexPath.row] 但我每次都遇到相同的错误.

I keep getting a fatal error: unexpectedly found nil while unwrapping an optional value. I have tried switching detailVC.label.text = "Test" to detailVC.label.text = names[indexPath.row] but I keep getting the same error every time.

我使用了相同的代码行来更改单元格的标签文本，没有错误，但是对于位于空白视图中心的这个标签，我似乎无法正确理解?关于需要改变什么的任何想法?

I used the same lines of code for changing the cell's label text, with no errors, but for this label in the center of a blank view I cannot seem to get it right? Any thoughts on what needs to be changed?

顺便说一下，detail view controller中的label是@IBOutlet weak var label: UILabel!

By the way, the label in the detail view controller is @IBOutlet weak var label: UILabel!

推荐答案

您不能在 prepareForSegue 中访问 DetailViewController 的 IBOutlets，因为它们是尚未连接.

You cannot access IBOutlets of DetailViewController in prepareForSegue because they are not connected yet.

正如评论中提到的，在 DetailViewController 中创建一个 String 属性，在 prepareForSegue 中设置它并设置 text DetailViewController 的 viewDidLoad 或 viewWillAppear 中标签的属性.

As mentioned in the comments create a String property in DetailViewController, set it in prepareForSegue and set the text property of the label in viewDidLoad or viewWillAppear of DetailViewController.

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