ios - 网点是零？

Question

我已经在 Storyboard中创建(并链接)了一些标签到标签，当我尝试修改文本时，我的应用程序抛出异常并卡住，因为它们显然是 nil。

代码:

import UIKit

class QuoteView : UITableViewController {
    @IBOutlet var quoteCategory: UILabel!
    @IBOutlet var quoteTitle: UILabel!
    @IBOutlet var quoteAuthor: UILabel!
    @IBOutlet var quoteContent: UILabel!
    @IBOutlet var quoteTimestamp: UILabel!
}

我试图在以前的 View Controller 的 prepareForSegue 方法中设置它们，如下所示:

overide func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { 
    if (segue.identifier == "indivQuoteSegue") { 
         let svc = segue.destinationViewController as! QuoteView 
         let quote = quoteArray[(tableView.indexPathForSelectedRow?.row)!];
         svc.quoteTitle.text = quote.getQuoteTitle() 
         svc.quoteAuthor.text = quote.getQuoteAuthor()   
         svc.quoteContent.text = quote.getQuoteContent() 
         svc.quoteCategory.text = quote.getCategory() 
         svc.quoteTimestamp.text = quote.getQuoteTimestamp() 
    } 
} 

Answer 1

在 prepareForSegue 中，你的导出还没有被初始化，所以你不能设置它们的属性。您应该创建 String 属性并设置它们，或者更好的是只传递您的 quote 对象。例如:

overide func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { 
if (segue.identifier == "indivQuoteSegue") { 
     let svc = segue.destinationViewController as! QuoteView 
     let quote = quoteArray[(tableView.indexPathForSelectedRow?.row)!];
     svc.quoteTitleString = quote.getQuoteTitle() 
     svc.quoteAuthorString = quote.getQuoteAuthor()   
     svc.quoteContentString = quote.getQuoteContent() 
     svc.quoteCategoryString = quote.getCategory() 
     svc.quoteTimestampString = quote.getQuoteTimestamp() 
} 
} 

然后在 QuoteView 的 viewDidLoad 中设置标签的文本

override func viewDidLoad(){
    self.quoteTitle.text = self.quoteTitleString
    etc...
}