Setup FileProvider from getFilesDir() which can access by others app?

Suppose I have a app A (com.xxx.aaa) has file provider come from getFilesDir() Having xml

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <files-path name="files" path="."/>
</paths>

AndroidManifest:

<provider
     android:name="android.support.v4.content.FileProvider"
     android:authorities="com.xxx.aaa.fileprovider"
     android:exported="false"
     android:grantUriPermissions="true">
     <meta-data
          android:name="android.support.FILE_PROVIDER_PATHS"
          android:resource="@xml/fileprovider_paths"/>
</provider>

On other app B (com.xxx.bbb) would like to ask app A to make some process on its file from getFilesDir(), assume app A already know app B filename (target.txt)

try{
    Intent intent = new Intent("com.xxx.aaa.DO_SOMETHING_ON_TARGET");
    intent.setClassName("com.xxx.aaa","com.xxx.aaa.TargetActivity");
    File file = new File("/data/data/com.xxx.aaa/files/target.txt");
    Uri contentUri = FileProvider.getUriForFile(context, "com.xxx.aaa.fileprovider", file);
    intent.setData(contentUri);
    intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    Log.d(TAG, "setted fileprovider uri: "+contentUri);
    context.startActivity(intent);
}catch(Exception e){
    Log.e(TAG, "getUriForFile failed", e);
}

It would output exception:

IllegalArgumentException: Failed to find configured root /data/data/com.xxx.aaa/files/target.txt

Is this approach only work within one app? And I have no choice to define custom key which both app understands and use it on intent.putExtra(key, ...)?

Is this approach only work within one app?

FileProvider.getUriForFile() is for the app's own FileProvider. App B does not have a FileProvider, let alone one configured for App A. Moreover, App B does not have access to the file, and therefore it cannot grant permission to any other app to access that file, as you are trying to do with FLAG_GRANT_READ_URI_PERMISSION.

And I have no choice to define custom key which both app understands and use it on intent.putExtra(key, ...)?

That would seem to be a straightforward approach.