Swift NSCoding不工作

Question

我在使用NSCodingSwift时遇到了麻烦.我试图实现协议,但每当我调用我的save()方法时我都会崩溃.Xcode让我上线了encodeWithCoder.这是我的代码,任何建议都会随之而来.

class CourseList: NSObject, NSCoding {
    ...

    init(coder aDecoder: NSCoder!){
        super.init()
        if aDecoder != nil {
            self.courses = aDecoder.decodeObjectForKey("courses") as Dictionary<String,course>
        }
    }

    func encodeWithCoder(aCoder: NSCoder!) {
        aCoder!.encodeObject(self.courses, forKey: "courses") // EXC_BAD_INSTRUCTOIN


    }
}

我写了save()并load()打电话给ViewController.

func save() {
    var archivedObject = NSKeyedArchiver.archivedDataWithRootObject(History)  //NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    var defaults = NSUserDefaults.standardUserDefaults()  //[defaults setObject:archivedObject forKey:<key_for_archived_object>];
    defaults.setObject(History.courses, forKey: "courses")
    defaults.synchronize()
}

func load() {
    var defaults = NSUserDefaults.standardUserDefaults()  // NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    var archivedObject = defaults.objectForKey("courses") as NSData  // NSData *archivedObject = [defaults objectForKey:<key_for_archived_object>];
    History = NSKeyedUnarchiver.unarchiveObjectWithData(archivedObject) as Dictionary<String,course>   //<your_class> *obj = (<your_class> *)[NSKeyedUnarchiver unarchiveObjectWithData:archivedObject];

}

Answer 1

自从提出这个问题以来,Swift已经发生了一些变化.我无法重现您所看到的错误,但我能够使用下面的代码使用Swift 1.0来使用NSCoding.

class CourseList: NSObject, NSCoding
{
    var myCourses: Dictionary<String, String>?

    override init() {}

    required init(coder aDecoder: NSCoder) {
        self.myCourses  = aDecoder.decodeObjectForKey("myCourses") as? Dictionary
    }

    func encodeWithCoder(aCoder: NSCoder) {
        if let courses = self.myCourses{
            aCoder.encodeObject(courses, forKey: "myCourses")
        }
    }

    func populateCourses() {
        self.myCourses = ["cs101": "Hello World"]
    }

    func save() {
        let data = NSKeyedArchiver.archivedDataWithRootObject(self)
        NSUserDefaults.standardUserDefaults().setObject(data, forKey: "courseList")
    }

    func clear() {
        NSUserDefaults.standardUserDefaults().removeObjectForKey("courseList")
    }

    class func loadSaved() -> CourseList? {
        if let data = NSUserDefaults.standardUserDefaults().objectForKey("courseList") as? NSData {
            return NSKeyedUnarchiver.unarchiveObjectWithData(data) as? CourseList
        }
        return nil
    }
}

加载已保存的实例或根据需要创建新实例

    // Try loading a saved version first
    if let courseLs = CourseList.loadSaved() {
        println("loaded Save CourseList")
    } else {
        // Create a new Course List
        let courseLs: CourseList = CourseList()
        courseLs.populateCourses()
        courseLs.save()
    }

Answer 2

class Student: NSObject, NSCoding {
    var name: String!
    var className: String!
    var rollNo: Int!
    var marks: [Float]!


    // MARK: NSCoding

    required convenience init(coder decoder: NSCoder) {
        self.init()
        self.name = decoder.decodeObjectForKey("name") as String?
        self.className = decoder.decodeObjectForKey("className") as String?
        self.rollNo = decoder.decodeIntegerForKey("rollNo")
        self.marks = decoder.decodeObjectForKey("marks") as [Float]!

    }

    func encodeWithCoder(coder: NSCoder) {
        coder.encodeObject(self.name, forKey: "name")
        coder.encodeObject(self.className, forKey: "className")
        coder.encodeInt(Int32(self.rollNo), forKey: "rollNo")
        coder.encodeObject(self.marks, forKey: "marks")

    }
}

上面的类字符串,整数,数组编码实现.

假设学生是班级学生的一个实例

存档

1. 文件系统 :

   NSKeyedArchiver.archiveRootObject(student, toFile: "Here give your file path")
   

2. NSUserDefaults:

   let data = NSKeyedArchiver.archivedDataWithRootObject(student)
   NSUserDefaults.standardUserDefaults().setObject(data, forKey: "student")
   

解除封存

1. 文件系统 :

   NSKeyedUnarchiver.unarchiveObjectWithFile(student, toFile: "Here give your file path")
   

2. NSUserDefaults:

   if let data = NSUserDefaults.standardUserDefaults().objectForKey("student") as? NSData {
       let student = NSKeyedUnarchiver.unarchiveObjectWithData(data)
   }
   

ADDIT:

保存/读取的文件路径

func saveFileLocation() -> String {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentDirectory = paths[0] as! String
    return documentDirectory.stringByAppendingPathComponent("savefile")
}