Android：范围存储将应用程序文件夹从外部目录移动到 Android/data/com.myapp

Question

I am planning to implement scoped storage for my existing app. All my app data is stored in External Memory in storage/emulated/0/MyAppName path. I have to move this data to private folder like Android/data/com.myapp . Can anyone provide some code snippet to help in this regard?

Answer 1

in this SO topic you have some examples how to move files to new directory (in short: use renameTo method from File class)

remember that when you update your targetSdkVersion and "turn on" Scoped Storage then you won't get access to old folder. at first release version with file-moving snippet, let users run your app for a while (most of active users will move files to new folder), then release new app version with Scoped Storage support

you have to take into account that some part of users may stay with (very) old app and some day will update straight to Scoped-Storage-supporting ( targetSdkVersion bumped up), they will lose their data (file access in prev folder). longer you will keep version pre-Scoped-Storage with moving files code on market - smaller part of users will lose data

Answer 2

You can also use App-specific files. first of all, let's consider your application id is com.myapp

now add the following to your manifiest file inside application attribute

<application...>            
    <provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="${applicationId}.provider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths" />
    </provider>
</application>

1. Now go to res directory in your project, right click on it and select new , then select Android Resource Directory .

2. Now select resource type as xml , write directory name as xml and sourece set as main src/main/res

3. Now create a new xml file inside the xml folder having name file_paths

4. And write following inside it.

    <?xml version="1.0" encoding="utf-8"?> <paths xmlns:android="http://schemas.android.com/apk/res/android"> <external-path name="my_images" path="Android/data/com.myapp/files/Pictures" /> <external-path name="my_documents" path="Android/data/com.myapp/files/Documents" /> <external-path name="my_videos" path="Android/data/com.myapp/files/Movies" /> </paths>

Now to use it you can use the following code

private File createImageFile(String fileName) throws IOException {
    File storageDir = activity.getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File imageFile = File.createTempFile(fileName, ".jpg", storageDir);
    return imageFile;
}

public Uri getFileUri(String fileName, String imageString) {
    File imageFile = null;
    Uri uri = null;

    try {
        imageFile = createImageFile(fileName);

        imageFile.createNewFile();
        FileOutputStream fo = new FileOutputStream(imageFile.getPath());
        fo.write(imageString.getBytes());
        fo.flush();
        fo.close();
    } catch (Exception e) {
        e.printStackTrace();
    }

    if (imageFile != null) {
        uri = FileProvider.getUriForFile(activity, "com.myapp", imageFile);
    }
    return uri;
}