ios - 为什么生成的 AppDelegate 文件有错误？

Question

当我创建一个新项目时生成的 AppDelegate xcode 中有错误，我正在努力调试，因为我是 swift 的新手。为什么生成的文件会返回错误？在创建新的 swift 项目时如何防止这种情况？

错误 1

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
    var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("Swift_Conversion.sqlite")
    var error: NSError? = nil
    var failureReason = "There was an error creating or loading the application's saved data."
    if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
        coordinator = nil
        //ERROR: EXTRA ARGUMENT 'ERROR' IN CALL
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason
        dict[NSUnderlyingErrorKey] = error
        error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
        NSLog("Unresolved error \(error), \(error!.userInfo)")
        abort()
    }

    return coordinator
}()

错误 2

func saveContext () {
    if let moc = self.managedObjectContext {
        var error: NSError? = nil
        if moc.hasChanges && !moc.save(&error) {
        //ERROR: CANNOT CONVERT VALUE OF TYPE 'INOUT NSERROR?'(AKA 'INOUT OPTIONAL<NSERROR>') TO EXPECTED ARGUMENT TYPE '()'
            NSLog("Unresolved error \(error), \(error!.userInfo)")
            abort()
        }
    }
}

我曾尝试手动调试它，但我在编辑 AppDelegate 和使用 swift 方面的经验不足让我失望，因为我删除的每个错误都伴随着一些新错误。

Answer 1

addPersistentStoreWithType 的方法签名已更改。它现在是 throwable 并且必须像这样使用:

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.
    print("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
    abort()
}

与 NSManagedObjectContext 上的 save 方法相同:

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
            print("Unresolved error \(nserror), \(nserror.userInfo)")
            abort()
        }
    }
}