使用FileManager将app里面的文字保存在txt里面

func createFile(){
let manager = FileManager.default
let urls: [URL] = manager.urls(for: .desktopDirectory, in: .userDomainMask)
let documentURL = urls.first!
let url = documentURL.appendingPathComponent("MeetLive", isDirectory: true)
var isDirectory: ObjCBool = ObjCBool(false)
let isExist = manager.fileExists(atPath: url.path, isDirectory: &isDirectory)
if !isExist {
  do {
    try manager.createDirectory(at: url, withIntermediateDirectories: true, attributes: nil)
  } catch {
    print("createDirectory error:\(error)")
  }
}}

func createTextFile(){
    let manager = FileManager.default
    let urls: [URL] = manager.urls(for: .desktopDirectory, in: .userDomainMask)
    let documentURL = urls.first!
    let url = documentURL.appendingPathComponent("/test1.txt", isDirectory: true)   // txt文件会自动创建，只要给个名称就行
    print("createTextFile=====url",url)
    var isDirectory: ObjCBool = ObjCBool(false)
    let isExist = manager.fileExists(atPath: url.path, isDirectory: &isDirectory)
    if !isExist {
        let string = ""
        do {
          try string.write(to: url, atomically: true, encoding: .utf8)
          // Data、Array、Dictionary、Image 都可以write
        } catch {
          print("write string error:\(error)")
        }
    }
}

    func weiteTextToFile(str:String){
let manager = FileManager.default
let urls: [URL] = manager.urls(for: .desktopDirectory, in: .userDomainMask)
let documentURL = urls.first!
let url = documentURL.appendingPathComponent("/test1.txt", isDirectory: true)

// 方法1:
guard let textdata = manager.contents(atPath: url.path) else {
  return
}
let readString = String(data: textdata, encoding: .utf8)
print("方法1：\(readString ?? "")")
if (readString ?? "").contains(str){
    return
}

guard let data = str.data(using: .utf8, allowLossyConversion: true) else {
  return
}
// 1.写在结尾
do {
  let writeHandler = try FileHandle(forWritingTo: url)
  writeHandler.seekToEndOfFile()
  writeHandler.write(data)
} catch {
  print("writeHandler error:\(error)")
}}