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？

这是下载文件到设备的代码：

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

您可以在应用启动时创建目录。 在第一个屏幕的 initState() 方法中执行逻辑。

例如

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 2

//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
    }
  }

Answer 3

据我所见，您没有在任何地方使用appDocDir 和appDocPath，因为您将文件保存在/sdcard/myapp 中。

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 sdcard 中。要么使用预定义的目录，如（文档、图片等），要么使用以storage/emulated/0 开头的设备根目录

Answer 4

这是在用户内部存储中创建文件夹的示例代码希望对您有所帮助

import 'dart:io' as Io;



Future _downloadImage() async {
try {
    // request runtime permission
    final permissionHandler = PermissionHandler();
    final status = await permissionHandler
        .checkPermissionStatus(PermissionGroup.storage);
    if (status != PermissionStatus.granted) {
      final requestRes = await permissionHandler
          .requestPermissions([PermissionGroup.storage]);
      if (requestRes[PermissionGroup.storage] != PermissionStatus.granted) {
        _showSnackBar('Permission denined. Go to setting to granted!');
        return _done();
      }
    }
  }
  var testdir =
  await new Io.Directory('/storage/emulated/0/MyApp').create(recursive: true);
  final filePath =
      path.join(testdir.path, Filename + '.png');
  print(filePath);
  final file = File(filePath);
  if (file.existsSync()) {
    file.deleteSync();
  }
 //save image to storage
  var request = await HttpClient().getUrl(Uri.parse(imageUrl));
  var response = await request.close();
  final Uint8List bytes = await consolidateHttpClientResponseBytes(response);
  final saveFileResult =
      saveImage({'filePath': filePath, 'bytes': bytes});
 _showSnackBar(
    saveFileResult
        ? 'Image downloaded successfully'
        : 'Failed to download image',
  );
} on PlatformException catch (e) {
  _showSnackBar(e.message);
} catch (e, s) {
  _showSnackBar('An error occurred');
  debugPrint('Download image: $e, $s');
}
return _done();
 }

Answer 5

首先你需要导入

1) 导入'dart:io'；

其次，您需要在 async/await 函数中为指定路径创建目录

2) 例如： await new Directory('/storage/emulated/0/yourFolder').create(recursive: true);