Question

我想要将cacheAirect的类的NSArray。我写了如下，但它返回false。你能告诉我如何解决这个问题吗？谢谢你的好意。

let paths2 = NSSearchPathForDirectoriesInDomains(
        .CachesDirectory,
        .UserDomainMask, true)
    let cachesPath: AnyObject = paths2[0]

    var cachedQuestions:NSArray = questions as NSArray
    let filePath = cachesPath.stringByAppendingPathComponent("CachedQuestions")

    class Dog {
        var id:Int?
        var name:String?
        init(id:Int, name:String) {
            self.id = id
            self.name = name
        }
    }

    var dogs = [Dog]()
    dogs.append(Dog(id:1, name:"taro"))
    dogs.append(Dog(id:2, name:"jiro"))
    var nsArrayDogs:NSArray = dogs as NSArray

    let success = nsArrayDogs.writeToFile(filePath, atomically: true)

    if success {
        println("save success")
    }

Answer 1

Xcode 7.3.1•Swift 2.2.1

您可以使您的Dog class NSCoding合规：

class Dog: NSObject, NSCoding {
    let id: Int
    let name: String
    required init(id: Int, name: String) {
        self.id = id
        self.name = name
    }
    required init(coder decoder: NSCoder){
        self.id = decoder.decodeObjectForKey("id") as? Int ?? 0
        self.name = decoder.decodeObjectForKey("name") as? String ?? ""
    }
    func encodeWithCoder(coder: NSCoder) {
        coder.encodeObject(id, forKey: "id")
        coder.encodeObject(name, forKey: "name")
    }
}

然后您可以将数组数据保存到磁盘，如下所示：

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        let dog1 = Dog(id: 1, name: "taro")
        let dog2 = Dog(id: 2, name: "jiro")
        do {
            let cachesDirectoryURL = try NSFileManager.defaultManager().URLForDirectory(.CachesDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: true)
            let array = [dog1, dog2]
            let fileURL = cachesDirectoryURL.URLByAppendingPathComponent("CachedQuestions.plist")
            let success = NSKeyedArchiver.archiveRootObject(array, toFile: fileURL.path!)
            print(success)
            // to load it from disk
            if let loadedArray = NSKeyedUnarchiver.unarchiveObjectWithFile(fileURL.path!) as? [Dog] {
                print(loadedArray.count)   // 2
            }
        } catch let error as NSError {
            print(error.localizedDescription)
        }
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

将类的NSArray保存到cacheDirectory

1 个答案: