安装应用程序时创建文件夹

Question

如何在设备存储中创建文件夹来保存文件？

这是将文件下载到设备的代码：

import 'package:flutter_downloader/flutter_downloader.dart';

onTap: () async { //ListTile attribute
   Directory appDocDir = await getApplicationDocumentsDirectory();                
   String appDocPath = appDocDir.path;
   final taskId = await FlutterDownloader.enqueue(
     url: 'http://myapp/${attach[index]}',
     savedDir: '/sdcard/myapp',
     showNotification: true, // show download progress in status bar (for Android)
     clickToOpenDownloadedFile: true, // click on notification to open downloaded file (for Android)
   );
},

Answer 1

从我看到的是，你没有在任何地方使用appDocDir和appDocPath，因为你正在/sdcard/myapp中保存文件。

请检查您是否要求并授予存储权限，并且无法像您一样将文件存储在SD卡中。使用预定义目录（如文档，图片等）或使用以storage/emulated/0开头的设备根目录

Answer 2

您可以在启动应用程序时创建目录。在你的第一个屏幕的initState()方法做逻辑。

防爆。

createDir() async {
  Directory baseDir = await getExternalStorageDirectory(); //only for Android
  // Directory baseDir = await getApplicationDocumentsDirectory(); //works for both iOS and Android
  String dirToBeCreated = "<your_dir_name>";
  String finalDir = join(baseDir, dirToBeCreated);
  var dir = Directory(finalDir);
  bool dirExists = await dir.exists();
  if(!dirExists){
     dir.create(/*recursive=true*/); //pass recursive as true if directory is recursive
  }
  //Now you can use this directory for saving file, etc.
  //In case you are using external storage, make sure you have storage permissions.
}

@override
initState(){
  createDir(); //call your method here
  super.initState();
}

您需要导入这些库：

import 'dart:io';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';

Answer 3

//add in pubspec.yaml
path_provider:

//import this
import 'dart:io' as io;
import 'package:path_provider/path_provider.dart';

//create Variable 
String directory = (await getApplicationDocumentsDirectory()).path;

//initstate to create directory at launch time
@override
  void initState() {
    // TODO: implement initState
    super.initState();
    createFolder();
  }

//call this method from init state to create folder if the folder is not exists
void createFolder() async {
    if (await io.Directory(directory + "/yourDirectoryName").exists() != true) {
      print("Directory not exist");
      new io.Directory(directory + "/your DirectoryName").createSync(recursive: true);
//do your work
    } else {
      print("Directoryexist");

//do your work
    }
  }