AppDelegate Swift 中的选项卡式应用程序和核心数据函数

Posted 2023-02-23

【中文标题】AppDelegate Swift 中的选项卡式应用程序和核心数据函数

【英文标题】：Tabbed Application and Core Data functions in AppDelegate Swift

【发布时间】：2016-06-15 08:27:08

【问题描述】：

我是 Swift 和 iPhone 应用程序的新手。最近我用选项卡式应用程序创建了一个项目。由于我已经完成了我的项目，最后一步是添加核心数据以保存我的信息。我决定用核心数据创建一个新的单视图应用程序，并将其核心数据功能从单视图应用程序 AppDelegate 复制到选项卡式应用程序 AppDelegate。

这是我复制的代码（从单视图应用程序到选项卡式应用程序，AppDelegate.swift）：

    func applicationWillTerminate(application: UIApplication) 
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    // Saves changes in the application's managed object context before the application terminates.
    self.saveContext()


// MARK: - Core Data stack

lazy var applicationDocumentsDirectory: NSURL = 
    // The directory the application uses to store the Core Data store file. This code uses a directory named "com.Spookas.bandymas" in the application's documents Application Support directory.
    let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
    return urls[urls.count-1]
()

lazy var managedObjectModel: NSManagedObjectModel = 
    // The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
    let modelURL = NSBundle.mainBundle().URLForResource("Model", withExtension: "momd")!
    return NSManagedObjectModel(contentsOfURL: modelURL)!
()

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = 
    // The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
    // Create the coordinator and store
    let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
    var failureReason = "There was an error creating or loading the application's saved data."
    do 
        try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
     catch 
        // Report any error we got.
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason

        dict[NSUnderlyingErrorKey] = error as NSError
        let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
        // Replace this with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
        abort()
    

    return coordinator
()

lazy var managedObjectContext: NSManagedObjectContext = 
    // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
    let coordinator = self.persistentStoreCoordinator
    var managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
    managedObjectContext.persistentStoreCoordinator = coordinator
    return managedObjectContext
()

// MARK: - Core Data Saving support

func saveContext () 
    if managedObjectContext.hasChanges 
        do 
            try managedObjectContext.save()
         catch 
            // Replace this implementation with code to handle the error appropriately.
            // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            let nserror = error as NSError
            NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
            abort()
        
    

我写的时候代码没有错误；但是，当我启动应用程序并执行任何应保存数据的方法时，我收到此错误：

2016-06-15 10:55:19.182 Taupyk![1387:32488] CoreData：加载失败 带有 URL 的 NSManagedObjectModel 'file:///Users/MyMac/Library/Developer/CoreSimulator/Devices/029E41C4-9E00-474A-BBA1-410D1211D39F/data/Containers/Bundle/Application/FE7605D7-A2F3-449E-8961-F0B33FCB4D15/Taupyk!.app /Model.mod/' 致命错误：在展开可选值时意外发现 nil

然后它指向这些代码行：

    lazy var managedObjectModel: NSManagedObjectModel = 
    // The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
    let modelURL = NSBundle.mainBundle().URLForResource("Model", withExtension: "momd")!
    return NSManagedObjectModel(contentsOfURL: modelURL)!
()

它说明了线程 1：EXC_BAD_INSTRUCTION(code=EXC_1386_INVOP, subcode=0x0)

我还从单视图应用程序项目中复制了数据模型并将其重命名为“模型”，但它仍然抛出错误

我看到有其他人和我一样，但是，他们能够解决问题，而我不能也不明白为什么即使我做了同样的事情也不起作用

提前感谢您的帮助

【参考方案1】：

您缺少实际的 CoreData 数据库。

向您的项目添加新文件 选择CoreData 选择数据模型 将您的数据模型称为“模型”（以匹配您的源代码）

注意，您也会在单视图项目中看到这一点。

【讨论】：

谢谢，成功了！关键是我的项目中已经有一个 coredata 数据库，但由于某种原因它不起作用。我决定按照你说的创建一个新的并删除旧的。

对不起，我想，但它说我需要有声望点或类似的东西才能这样做！ :(

【参考方案2】：

为您的项目选择新文件。

2.core数据->数据模型->点击下一步按钮->点击创建按钮。

您的项目模型添加实体和实体名称。

【讨论】：

这真的会给接受的答案增加什么吗？