Swift 2 调用中的额外参数“错误”答案

【问题标题】：Swift 2 Extra argument ' error' in callSwift 2 调用中的额外参数“错误”
【发布时间】：2015-06-29 10:34:21
【问题描述】：

您好，我正在使用 Xcode 7 将我的项目从 Swift 更新到 Swift2，我收到了这个 CoreData 错误：

Extra argument 'error' in call

在这一行

if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {

编辑

这是我的代码：

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
        // The persistent store coordinator for the application. This implementation creates and return 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
        var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
        let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("Xipe_Tech.sqlite")
        var error: NSError? = nil
        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)
            coordinator = nil
            // 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
            error = 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 \(error), \(error!.userInfo)")
            abort()

        } catch let error as NSError {
            print(error.localizedDescription)

        }

        return coordinator
    }()

现在我在第一行出现错误我该如何解决？谢谢

【问题讨论】：

Swift: Extra argument 'error' in call 的可能重复项

标签： ios xcode swift2 xcode7

【解决方案1】：

Swift 2 现在提供了一种 try/catch 机制，并且 Cocoa API 已被重写为使用它来代替传统的 Objective C 方式返回错误。

你现在应该这样做：

do {
    try coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
} catch let error as NSError {
    print(error.localizedDescription)

}

【讨论】：

现在我在这一行得到错误：`lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {`错误是：Call can throw, but is not marked as try and the error is not handling
请出示您的代码。但似乎您在调用函数之前没有添加 try 注释
您可以考虑观看 WWDC 视频并实际了解正在发生的事情，而不仅仅是更改代码。

【解决方案2】：

其他遇到此问题的人只需在下面使用它。我遇到过同样的问题。 Apple 用 do try 流行语替换了原来的“if coordinator!.addPersistentStoreWithType”。

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
    }()

【讨论】：