主明细应用，传递对象

Posted 2023-03-12

【中文标题】主明细应用，传递对象

【英文标题】：Master detail application, passing object

【发布时间】：2015-06-24 02:16:47

【问题描述】：

我确定我忽略了一些基本的东西，但我对此感到沮丧。我无法访问在行中选择并传递给详细视图的对象的属性。以下是相关代码：

AppDelegate：

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool 

    // Override point for customization after application launch.
    let splitViewController = self.window!.rootViewController as! UISplitViewController
    let navigationController = splitViewController.viewControllers[splitViewController.viewControllers.count-1] as! UINavigationController
    navigationController.topViewController!.navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem()
    splitViewController.delegate = self

    let masterNavigationController = splitViewController.viewControllers[0] as! UINavigationController
    let controller = masterNavigationController.topViewController as! MasterViewController
    controller.managedObjectContext = self.managedObjectContext
    return true

主视图控制器：

override func viewDidLoad() 
    super.viewDidLoad()
    if let split = self.splitViewController 
        let controllers = split.viewControllers
        self.detailViewController = (controllers[controllers.count-1] as! UINavigationController).topViewController as? DetailViewController
    

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) 
    if segue.identifier == "showDetail" 
        if let indexPath = self.tableView.indexPathForSelectedRow 
            let object = matchups[indexPath.row]
            let controller = (segue.destinationViewController as! UINavigationController).topViewController as! DetailViewController
            controller.detailItem = object
            controller.navigationItem.leftBarButtonItem = self.splitViewController?.displayModeButtonItem()
            controller.navigationItem.leftItemsSupplementBackButton = true
            controller.detailItem = matchups[indexPath.row]
        
    

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) 
    if (detailViewController != nil) 
        self.detailViewController!.detailItem = matchups[indexPath.row]
    

DetailViewController：

var detailItem: AnyObject? 
    didSet 
        self.configureView()
    



func configureView() 
    // Update the user interface for the detail item.
    if let detail = self.detailItem 
        if let label = self.detailDescriptionLabel 
            label.text =  detail //** This is where the problem lies **//
        
    

这是 Apple 模板代码。我也尝试过使用替代方法的网络教程，但我仍然遇到问题。我错过了什么？提前致谢。

【参考方案1】：

Test 是 String，DetailItem 是 AnyObject?。在分配之前，您需要将 detailItem 转换为所需的类型。

什么是 detailItem 类型？它只是一个字符串吗？在这种情况下，你可以写成？在你的 if let 定义中，这就足够了。

【讨论】：

我知道我遗漏了一些基本的东西。非常感谢。