如何向基于文档的 Swift 3 应用程序添加简单的保存加载功能？

Question

我目前正在研究 Swift（只是出于爱好），并试图弄清楚我应该如何在基于文档的 swift 应用程序中将函数保存和加载到 document.swift 文件中？我想知道如何保存和加载简单的 txt 文件。我正在使用 NSTextView，所以我想我必须将其更改为 NSString？

目前这些功能如下：

override func data(ofType typeName: String) throws -> Data {
        // Insert code here to write your document to data of the specified type. If outError != nil, ensure that you create and set an appropriate error when returning nil.
        // You can also choose to override fileWrapperOfType:error:, writeToURL:ofType:error:, or writeToURL:ofType:forSaveOperation:originalContentsURL:error: instead.
        throw NSError(domain: NSOSStatusErrorDomain, code: unimpErr, userInfo: nil)      
    }

override func read(from data: Data, ofType typeName: String) throws {
        // Insert code here to read your document from the given data of the specified type. If outError != nil, ensure that you create and set an appropriate error when returning false.
        // You can also choose to override readFromFileWrapper:ofType:error: or readFromURL:ofType:error: instead.
        // If you override either of these, you should also override -isEntireFileLoaded to return false if the contents are lazily loaded.
        throw NSError(domain: NSOSStatusErrorDomain, code: unimpErr, userInfo: nil)

    }

Answer 1

在您的 document.swift 文件中，以下这些函数将加载并设置您的文本视图字符串值。

希望这会有所帮助！

var content = ""
override func makeWindowControllers() {
    //Make the window controller
    let storyboard = NSStoryboard(name: "Main", bundle: nil)
    let windowController = storyboard.instantiateController(withIdentifier: "Document Window Controller") as! NSWindowController
    self.addWindowController(windowController)

    //Access the view controller
    let vc = windowController.contentViewController as! ViewController
    //Set the text view string to the variable that was loaded
    vc.textView.string = content
}

override func data(ofType typeName: String) throws -> Data {
    //Access the current view controller
    if let vc = self.windowControllers[0].contentViewController as? ViewController {
        //Get the textView's String Value; or call a function that will create a string of what needs to be saved
        return vc.textView.string?.data(using: String.Encoding.utf8) ?? Data()
    }else {
        throw NSError(domain: NSOSStatusErrorDomain, code: unimpErr, userInfo: nil)
    }
}

override func read(from url: URL, ofType typeName: String) throws {
    do {
        //Set a string variable to the loaded string
        //We can't directly set the text views string value because this function is called before the makeWindowControllers() so now text view is created yet.
        content = try String(contentsOf: url, encoding: String.Encoding.utf8)
    }catch {
        throw NSError(domain: NSOSStatusErrorDomain, code: unimpErr, userInfo: nil)
    }
}