Flutter: How to securely share data among two separate android apps?

Question

I need to share some particular data among two separate apps on android, preferably make some kind of shared folder which can be accessed by both the apps only.

Why? I need a single sign on functionality between two separate apps.

Till now I have been authenticating users using JWT tokens by storing them in sharedpreferences (storing them to maintain the signin) and clearing the shared prefs when the user logs out (along with hitting the api which changes the token).

Now I have another app which works with the same token.

What's required: you sign into one and another one automatically signs in. So, my plan is to store the token on the device which in turn can be accessed by both the apps.

I know I will need an active directory for a secure SSO but I am okay with not having a 100% security as of now, the question still remains about how to share data among apps.

I would suggest, in the signin, have a key in the backend user data as isSignedIn, update it, during signing in and signing out. With that, you can check for the key while opening up the app, whether the user is signed in other devices or not. Let me know if that helps or you don't get the idea — Alok
– Alok, Commented May 26, 2020 at 6:53
Please check medium.com/@ranaranvijaysingh9/… Shared services normally has been used to share data between two apps — Flutterian
– Flutterian, Commented May 26, 2020 at 7:06

CopsOnRoad · Accepted Answer · 2020-05-29 01:12:51Z

2

I'm just giving you an idea, and not to mention this ONLY works in Android.

From your 1st app (primary), create a file (for now, I am creating a .txt file) in device external storage using path_provider,

Future<void> _createAndWrite() async {
  // Get external directory
  final directory = (await Directory('storage/emulated/0/Sharing Folder').create()).path;

  // Create your file
  final file = File('$directory/any_file.txt');
  await file.create();

  // Write to the file
  await file.writeAsString('Content to write');
}

In your 2nd app, you can read the contents of the file with something like:

Future<void> _readFile() async {
  // Get external directory
  final directory = (await Directory('storage/emulated/0/Sharing Folder').create()).path;

  // Get the file
  final file = File('$directory/any_file.txt');

  // Read it
  final content = await file.readAsString();
}

Make sure in both apps you have declared the following permission:

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

answered May 29, 2020 at 1:12

CopsOnRoad

271k97 gold badges702 silver badges471 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user321553125 Over a year ago

But other apps on device will also be able to access this .txt right?

CopsOnRoad Over a year ago

Yes, you're right. But you mentioned in your post that for now you're not concerned with security part, or you may want to create a different type of file which can allow encryption/decryption.

Collectives™ on Stack Overflow

Flutter: How to securely share data among two separate android apps?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related