.documentDirectory

🌀 FileManager

📗 參考：Swift Playgrounds ⟩ Image Gallery (Data Model: Gathering Image URLs)

import Foundation

extension FileManager {
    /// URL of the app's document directory.
    var documentDirectory: URL? {
        urls(for: .documentDirectory, in: .userDomainMask).first
    }
}

💈範例

📗 參考：Paul ⟩ Writing data to the documents directory

struct ContentView: View {
    var body: some View {
        VStack {
            Text("Hello World").onTapGesture {
                
                // 🌀 FileManager + .documentDirectory
                guard let dir = FileManager.default.documentDirectory else {
                    fatalError("No Documents directory!")
                }
                
                // ⭐️ path to `Documents/message.txt`
                let url = dir.appendingPathComponent("message.txt")
                
                do {
                    let str = "Test Message"
                    // ⭐️ write: String -> file (UTF8 encoded)
                    try str.write(to: url, atomically: true, encoding: .utf8)
                    // ⭐️ read: file -> String (UTF8 decoded?)
                    let msg = try String(contentsOf: url)
                    
                    print(msg)    // "Test Message"
                } catch {
                    print(error.localizedDescription)
                }
            }
        }.padding()
    }
}

📗 參考

• Paul ⟩ Writing data to the documents directory

📘 手冊

• Foundation ⟩ NSString ⟩

  • write(to:atomically:encoding:)
  • init(contentsOf:encoding:)

🗣 討論

• URL to user's documents directory is empty
• Simplify creating file URL in a SearchPathDirectory e.g. DocumentDirectory
• Is it safe to force unwrap FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first! in Swift? (⭐️ my question)

❓

問：「 urls(for: .documentDirectory, in: .userDomainMask).first有可能是 nil 嗎❓ 」

👉 StackOverflow