【Swift】FileManagerでファイルを保存！操作方法や格納場所

├── AppData
│ ├── Documents
│ ├── Library
│        ├── Application Support
│        ├── Caches
│        ├── Preferences
│        ├── Saved Application State
│        └── SplashBoard
│ ├── SystemData
│ └── tmp

class FileManager : NSObject

FileManager.default

FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!

FileManager.default.urls(for: .libraryDirectory, in: .userDomainMask).first!

FileManager.default.urls(for: .cacheDirectory, in: .userDomainMask).first!

NSTemporaryDirectory()

NSHomeDirectory()  // Homeディレクトリのパス
NSHomeDirectory() + "/Documents" // Documentsディレクトリのパス
NSHomeDirectory() + "/Library"   // Libraryディレクトリのパス

let str =  NSHomeDirectory() + "/Documents"
let url = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
dump(type(of: str)) // String.Type
dump(type(of: url)) // Foundation.URL.Type

file:///var/mobile/Containers/Data/Application/085DB140-E500-4561-8EA3-A6AF0748AD27/Documents

let url : URL = URL(string:"https://www.amefure.com")!

func writingFile(_ text:String) {
    // Documentsディレクトリまでのパスを生成
    guard let docURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else{
        fatalError("URL取得失敗")
    }
    // ファイル名を含めたフルパスを生成
    let fullURL = docURL.appendingPathComponent("sample.txt")

    do {
        // 書き込み処理
        try text.write(to: fullURL,atomically: true,encoding: .utf8)
    } catch{
        print("書き込み失敗")
    }         
}

let fileManager = FileManager.default
let docURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first
// Optional(file:///〜

func readingFile()->String?{
    guard let docURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else{
        fatalError("URL取得失敗")
    }
    let fullURL = docURL.appendingPathComponent("sample.txt")
    do {
        let textData = try String(contentsOf: fullURL, encoding: .utf8)
        return textData
    } catch {
        return nil
    }
}

func removeFile(){
    let fileManager = FileManager.default
    guard let docURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first else{
        fatalError("URL取得失敗")
    }
    let fullURL = docURL.appendingPathComponent("sample.txt")
    do {
        try fileManager.removeItem(at: fullURL)
    } catch {
        print(error.localizedDescription)
    }
}

func copyFile(){
    let fileManager = FileManager.default
    guard let atURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first else{
        fatalError("URL取得失敗")
    }
    guard let toURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first else{
        fatalError("URL取得失敗")
    }
    let fullAtURL = atURL.appendingPathComponent("sample.txt")
    let fullToURL = toURL.appendingPathComponent("/test/sample.txt")
    do {
        try fileManager.copyItem(at: fullAtURL, to: fullToURL)
    } catch {
        print(error.localizedDescription)
    }
}

func createFile() {
    let fileManager = FileManager.default
    // String型のDocPathを作成
    let docPath =  NSHomeDirectory() + "/Documents"
    let filePath = docPath + "/sample.txt"
    
    if !fileManager.fileExists(atPath: filePath) {
        fileManager.createFile(atPath:filePath, contents: nil, attributes: [:])
    }else{
        print("既に存在します。")
    }
}

if !fileManager.fileExists(atPath: filePath) {
    fileManager.createFile(atPath:filePath, contents: nil, attributes: [:])
}else{
    print("既に存在します。")
}

The file “sample.txt” doesn’t exist.
// ファイル「sample.txt」は存在しません。

The file “sample.txt” couldn’t be opened because there is no such file.
// そのようなファイルがないため、ファイル「sample.txt」を開くことができませんでした

func createDirectory(){
    let fileManager = FileManager.default
    let docPath =  FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
    let directory = docPath.appendingPathComponent("Test", conformingTo: .directory)
    do {
        try fileManager.createDirectory(at: directory, withIntermediateDirectories: true, attributes: nil)
    } catch {
        print("失敗しました")
    }
}