NSCoding encodeObject错误

Question

导入UIKit

类事件: NSObject，NSCoding {

// MARK: Properties
var name: String
var created_at: String
var stands:[Stand?]

// MARK: Archiving Paths

static let DocumentsDirectory = NSFileManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask).first!
static let ArchiveURL = DocumentsDirectory.URLByAppendingPathComponent("events")


// MARK: Types

struct PropertyKey {
    static let nameKey = "name"
    static let createdAtKey = "created_at"
    static let standsAtKey = "stands"

}

// MARK: Initialization
init?(name: String, created_at: String, stands:[Stand?]) {
    // Initialize stored properties.
    self.name = name
    self.created_at = created_at
    self.stands = stands

    super.init()

    // Initialization should fail if there is no name or if no created_at.
    if name.isEmpty || created_at.isEmpty {
        return nil
    }
}

// MARK: NSCoding
func encodeWithCoder(aCoder: NSCoder) {
    aCoder.encodeObject(name, forKey: PropertyKey.nameKey)
    aCoder.encodeObject(created_at, forKey: PropertyKey.createdAtKey)
    aCoder.encodeObject(stands, forKey: PropertyKey.standsAtKey)

}

required convenience init?(coder aDecoder: NSCoder) {
    let name = aDecoder.decodeObjectForKey(PropertyKey.nameKey) as! String

    let created_at = aDecoder.decodeObjectForKey(PropertyKey.createdAtKey) as! String

    let stands = aDecoder.decodeObjectForKey(PropertyKey.standsAtKey) as! [Stand?]

    // Must call designated initializer.
    self.init(name: name, created_at: created_at, stands: stands)
}

}

我从"aCoder.encodeObject(stands，forKey: PropertyKey.standsAtKey)“中得到错误，说”无法将typeStand?的值转换为预期的参数类型'AnyObject?'“

我使用NSCoding来保存带有空看台数组的对象，然后检索它并更新这个类(事件)的看台属性。

Answer 1

除非你的类"Stand“也兼容NSCoding，否则你不能对你的自定义类"Event”进行编码。

Answer 2

在Swift 4中，您可以遵循Codable协议进行编码和解码

class Test: Codable {

}

有关更多信息，请阅读https://developer.apple.com/documentation/swift/codable