保存到本地应用程序目录时没有任何反应？ 扑

Question

I'm picking an image from gallery, and then I should save it to the App Local Directory , But that directory is never created!

I'm using image_picker and path_provider libraries, and used no permission.

Inside Press Button function:

getImageIntoLocalFiles(ImageSource.gallery); //call getImage function

The getImage function:

Future getImageIntoLocalFiles(ImageSource imageSource) async {

    final ImagePicker _picker = ImagePicker();

    // using your method of getting an image
    final XFile? image = await _picker.pickImage(source: imageSource);

    //debug
    print('${image?.path} ---image path'); //returns /data/user/0/com.ziad.TM.time_manager/cache/image_picker6496178102967914460.jpg

    // getting a directory path for saving
    Directory appDocDir = await getApplicationDocumentsDirectory();
    String appDocPath = appDocDir.path;

    //debug
    if(image != null) print('$appDocPath ---local directory path'); //return /data/user/0/com.ziad.TM.time_manager/app_flutter

    // copy the file to a new path
    await image?.saveTo('$appDocPath/image1.png');
  }

I don't understand where is the problem as there is no errors and I can't find a documentation explaining this.

com.ziad.TM.time_manager is never actually created

Answer 1

I solved just by using:

setDestinationInExternalFilesDir(context, relativePath, filename);

Instead of:

setDestinationInExternalPublicDir(relativePath, filename);

My relative path is:

Environment.getExternalStorageDirectory().getPath() + "MyExternalStorageAppPath"

I also have in my manifest:

android:requestLegacyExternalStorage="true"

To use Legacy storage management (Shared Storage) instead of new storage management (Scoped Storage) used from Android 10 and above.

Remember that by using "setDestinationInExternalFilesDir" files will be download to the external memory dedicated to your app, so: "external/Android/data/your_app_name/path_you_used_on_function".

Answer 2

To save the files, please follow below instructions.

find the correct path of the location you want to save by using ext_storage or path_provider . You will need this permission

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> 

on Android 10 you need this in your manifest

<application
      android:requestLegacyExternalStorage="true"

on Android 11 use this instead

<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />

Remember to ask for them using permission_handler

And to store file, please call below method

static Future saveInStorage(
      String fileName, File file, String extension) async {
    await _checkPermission();
    String _localPath = (await ExtStorage.getExternalStoragePublicDirectory(
        ExtStorage.DIRECTORY_DOWNLOADS))!;
    String filePath =
        _localPath + "/" + fileName.trim() + "_" + Uuid().v4() + extension;

    File fileDef = File(filePath);
    await fileDef.create(recursive: true);
    Uint8List bytes = await file.readAsBytes();
    await fileDef.writeAsBytes(bytes);
  }

Answer 3

according to flutter's documentation

getApplicationDocumentsDirectory : On Android, this uses the getDataDirectory API on the context. Consider using getExternalStorageDirectory instead if data is intended to be visible to the user.

So, by changing getApplicationDocumentsDirectory() to getExternalStorageDirectory() the directory is created and the file is successfully saved!!

---

I also found a way to create a new custom folder inside:

String dirToBeCreated = "<New Folder Name>";

    if(baseDir != null) {
      String finalDir = join(baseDir.path, dirToBeCreated);
      var dir = Directory(finalDir);

      bool dirExists = await dir.exists();
      if (!dirExists) {
        dir.create(
            /*recursive=true*/); //pass recursive as true if directory is recursive
      }

and don't forget to pass dir.path to saveTo() parameter (a string path not a Directory)