Question

我想保存以下数据：

class Book: NSObject, NSCoding {

var title: String
var chapter: [Chapter]

struct Chapter {
    var chapTitle: String
    var texte: [Texte]
}

struct Texte {
    var description: String
    var texte: [String]
    var position: [Int]
    var hidden: [Int?]
}

我目前正在使用NSCoder保存Book类：

static let DocumentsDirectory = FileManager().urls(for: .documentDirectory, in: .userDomainMask).first!
static let ArchiveURL = DocumentsDirectory.appendingPathComponent("learn")


struct PropertyKey {
    static let title = "title"
    static let chapter = "Chapter"
}

//MARK: - Initialization
init?(title: String, chapter: [Book.Chapter]) {        
    self.title = title
    self.chapter = chapter
}

//MARK: - NSCoding
func encode(with aCoder: NSCoder) {
    aCoder.encode(title, forKey: PropertyKey.title)
    aCoder.encode(chapter, forKey: PropertyKey.chapter)
}

required convenience init?(coder aDecoder: NSCoder) { 
    let title = aDecoder.decodeObject(forKey: PropertyKey.title) as! String
    let chapter = aDecoder.decodeObject(forKey: PropertyKey.chapter) as! [Book.Chapter]

    self.init(title: title, chapter: chapter)
}

有了这个，我可以保存本书的title和一个空数组chapter。

但是当我尝试将chapTitle和texte添加到Book对象时，我收到以下错误：

由于未捕获的异常'NSInvalidArgumentException'而终止应用程序，原因：' - [ SwiftValue encodeWithCoder：]：无法识别的选择器发送到实例0x60000066dec0'

这是否意味着无法保存结构？我应该改变什么？

Answer 1

如果你能把书作为一个结构，你最好使用codable。

static func saveData (books: [Book]) throws
{
     let encoded = try JSONEncoder().encode(books)
     try encoded.write(to: ArchiveURL)
     print("Books saved")
}

保存

//retrive data from it's saved place static func loadData() throws -> [Book] { let data = try Data(contentsOf: ArchiveURL) return try JSONDecoder().decode([Book].self, from: data) }

Retrive

let directory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] + "/learn/" let ArchiveURL = URL(fileURLWithPath: directory)

同时编辑顶部的变量

jQuery("#media-uploader").dropzone({ url: your_posting_url, acceptedFiles: 'image/jpeg', addedfile:function (file) { if( your condition ){ // okay ! } else { // not okay ! this.removeFile(file); } }, ... etc ... });

使用NSCoding保存结构

1 个答案: