在 Swift 中将 JSON 字典导入核心数据

Posted 2023-03-05

【中文标题】在 Swift 中将 JSON 字典导入核心数据

【英文标题】：Importing JSON dictionary to Core Data in Swift

【发布时间】：2014-11-10 21:57:20

【问题描述】：

我在使用 Swift 将 JSON 字典中的布尔值导入到下面的 Exercises 对象时遇到了一些麻烦。 Stretch 和 Equipment 对象非常简单。我知道这很容易，但是我找不到可以建模的示例。这是我的数据模型：

Stretch 对象是我的主要实体。 Equipment 对象将包含字符串。 Exercises 对象属性是布尔值。

    let jsonURL = NSBundle.mainBundle().URLForResource("seed", withExtension: "json")!
    let jsonData = NSData(contentsOfURL: jsonURL)

    var error: NSError?
    let jsonArray = NSJSONSerialization.JSONObjectWithData(jsonData!, options: nil, error: &error) as NSArray

    // Inserts attributes for database

    let entity = NSEntityDescription.entityForName("Stretch", inManagedObjectContext: coreDataStack.context)!

    var counter = 0

    for jsonDictionary in jsonArray 

        counter++
        // listing of columns in JSON seed file
        let stretchDescription = jsonDictionary.valueForKey("stretchDescription") as String
        let generalArea = jsonDictionary.valueForKey("generalArea") as String
        let muscleGroup = jsonDictionary.valueForKey("muscleGroup") as String
        let equipmentCode = jsonDictionary.valueForKey("equipmentCode") as String
        let sideMultiplier = jsonDictionary.valueForKey("sideMultiplier") as NSNumber
        let advanced = jsonDictionary.valueForKey("advanced") as Bool
        let photo = jsonDictionary.valueForKey("photo") as NSData
        let runningOrWalking = jsonDictionary.valueForKey("runningOrWalking") as Bool
        let cycling = jsonDictionary.valueForKey("cycling") as Bool
        let weightLifting = jsonDictionary.valueForKey("weightLifting") as Bool
        let aerobics = jsonDictionary.valueForKey("aerobics") as Bool
        let raquetSports = jsonDictionary.valueForKey("raquestSports") as Bool
        let golf = jsonDictionary.valueForKey("golf") as Bool
        let yoga = jsonDictionary.valueForKey("yoga") as Bool
        let equipmentDescription = jsonDictionary.valueForKey("equipmentDescription") as String

        let stretch = Stretch(entity: entity, insertIntoManagedObjectContext:coreDataStack.context)

        stretch.stretchDescription = stretchDescription
        stretch.generalArea = generalArea
        stretch.muscleGroup = muscleGroup
        stretch.equipmentCode = equipmentCode
        stretch.sideMultiplier = sideMultiplier
        stretch.advanced = advanced
        stretch.photo = photo

        // Insert Equipment object
        let equipmentEntity = NSEntityDescription.entityForName("Equipment", inManagedObjectContext: coreDataStack.context)
        let equipmentDescriptionObject = Equipment(entity: equipmentEntity!, insertIntoManagedObjectContext: coreDataStack.context)

        stretch.equipmentUsed = equipmentDescriptionObject

        // Figure out exercises object
        let exercise = NSEntityDescription.entityForName("Exercises", inManagedObjectContext: coreDataStack.context)
        let exerciseObject = Exercises(entity:exercise!, insertIntoManagedObjectContext: coreDataStack.context)

这就是我卡住的地方。我将如何完成为练习对象添加属性？

【参考方案1】：

我正在检查这个库（同步），它看起来很棒，可以将 JSON 对象转换为核心数据对象： https://github.com/hyperoslo/Sync

【参考方案2】：

这就是我卡住的地方。我将如何完成为练习对象添加属性？

与您向Stretch 对象添加属性的方式相同。您可以通过点符号轻松访问和设置Exercise 属性。

let exercise = NSEntityDescription.entityForName("Exercises", inManagedObjectContext: coreDataStack.context)
let exerciseObject = Exercises(entity:exercise!, insertIntoManagedObjectContext: coreDataStack.context)
exerciseObject.aerobics = aerobics

【讨论】：

谢谢！在教程中遵循是一回事，但有时非常简单的事情比我参与时更难；）