Tag Archives: Scoped Storage

Bringing modern storage to Viber’s users

This blogpost is a collaboration between Google and Viber. Authored by Kseniia Shumelchyk from Google and Anton Novikov, Sergey Kozlov from Viber.

As a messaging app, Viber needs to store, process and share a significant amount of data. Viber aims to give its users an easy, fast, reliable and secure communication platform by providing an intuitive interface and operating with files in a privacy-preserving way. We believe the modern scoped storage paradigm provides this foundation for app developers and users.

Scoped storage was introduced in Android 10 with further improvements in Android 11 to provide better protection to app and user data on a platform level. Due to Viber's complexity, the team opted to incrementally implement the changes that were required to comply with scoped storage.

In this article, we’ll share how Viber handled the migration to scoped storage, focusing on what they did to optimize working with media files and other data in the app.

Managing storage across Android versions

Android’s storage model has evolved to adapt to changing privacy considerations, leading to the changes in the storage system APIs. Let’s take a look at key platform changes that affected the legacy Viber implementation.

Media directories

Scoped storage changes the way that apps store and access files on a device's external storage. Viber needed to evaluate the differences between the existing app's storage model and updated platform guidelines, followed by gradual application changes to work with files in scoped storage. Therefore Viber invoked the requestLegacyExternalStorage flag to temporarily opt-out of scoped storage on Android 10 until the app was fully compatible.

In order to adjust their app experience to scoped storage, Viber now contributes public media files to well-defined media collections using the MediaStore API. This way, the files are accessible in a device gallery, and can be read by other apps with the storage permission. Private media files are stored in the app-specific directory on external storage and are accessed via the internal ContentProvider.

Storage permissions

The other notable update is related to changes in the storage permissions model: Apps in scoped storage have unrestricted access to their app-specific directories on external storage and can contribute to well-defined media collections without requesting a runtime permission. This change will help Viber provide more granular control to their users:

“This addition supports our efforts to provide our users with the best security and privacy solutions we can provide supported by the Android OS, users will benefit from this added security later without needing to opt-in. We also added a new ‘Save to gallery’ option allowing users to choose to make their photos readable by other apps or not. Because chats may contain private images or videos, it’s important to give users the ability to hide these files from the gallery. This change gives users additional control over the content included in their Viber messages.“ said Anton Novikov and Sergey Kozlov from Viber.

Accessing files outside of app-specific directory

Previously, Viber created and consumed files in a custom top level directory and depended on file path access. With scoped storage, saving app files to a top level directory became an anti-pattern, so Viber has followed best practices to update their implementation to store media files from the chats only in locations that are accessible in scoped storage.

However, to reduce the complexity of migration, Viber decided to keep their own top level directory for Android 10 and below, storing only the media files that are not exposed to the device’s Gallery app, while for Android 11 and above this directory is used in read-only mode to provide backward compatibility.

Another use case that Viber has been refining is sharing files in the chats. The updated storage runtime permission gives read access only to the images, videos and audio files that are available through MediaProvider. Starting from Android 11, the only way for Viber to access non-media files created by other apps is by using the Storage Access Framework document picker, which they had already utilized in a different part of their app.

App-specific files within external storage

In the scoped storage environment, app-specific directories on external storage are becoming private from other apps. This change has helped Viber leverage its use of external storage for storing private user files:

”We find change to app-specific directories to be useful, because it will help to ensure that personal chats are protected and backed with platform security.” said Anton Novikov from Viber. Learn more about how to access app-specific files.

Single interface to access storage

Because Viber targets a large audience running on Android 4.2 and above, they introduced an abstraction layer that aids them in managing storage access efficiently across all supported Android versions and with their use cases in mind.

Previously, Viber heavily used File API to access files, including files in legacy storage locations. Further, they stored absolute file paths for entries in the local database to keep the user's conversation history.

To standardize access to this conversation history and thus ensure that users don’t lose access to their files, Viber replaced absolute file paths with content URIs. In the new implementation, the app is accessing files only via content providers:

  • Internal FileProvider for Viber app-specific directories.
  • External file providers available in the Android framework, such as MediaStore or Storage Access Framework, or those belong to another app that shares files with Viber through Intent.ACTION_SEND.

By using a consistent ContentProvider layer, the ContentResolver gives the app a unified interface to access the file content.

This approach has also helped Viber optimize the network layer and define a universal Loader abstraction to upload/fetch and to read/store different types of media files like voice messages, chat images and stickers.


Android 11 further enhances scoped storage, which provides better protection of app and user data and makes the transition easier for developers. It’s amazing to see many apps like Viber are migrating to take advantage of scoped storage since Android 10.

We hope Viber’s story is useful and will inspire you to modernize your Android apps as well. Learn more about Android storage use cases and best practices.

Android Q Scoped Storage: Best Practices and Updates

Posted by Jeff Sharkey, Software Engineer, and Seb Grubb, Product Manager

Application Sandboxing is a core part of Android’s design, isolating apps from each other. In Android Q, taking the same fundamental principle from Application Sandboxing, we introduced Scoped Storage.

Since the Beta 1 release, you’ve given us a lot of valuable feedback on these changes -- thank you for helping shape Android! Because of your feedback, we've evolved the feature during the course of Android Q Beta. In this post, we'll share options for declaring your app’s support for Scoped Storage on Android Q devices, and best practices for questions we've heard from the community.

Updates to help you adopt Scoped Storage

We expect that Scoped Storage should have minimal impact to apps following current storage best practices. However, we also heard from you that Scoped Storage can be an elaborate change for some apps and you could use more time to assess the impact. Being developers ourselves, we understand you may need some additional time to ensure your app’s compatibility with this change. We want to help.

In the upcoming Beta 3 release, apps that target Android 9 Pie (API level 28) or lower will see no change, by default, to how storage works from previous Android versions. As you update your existing app to work with Scoped Storage, you’ll be able to use a new manifest attribute to enable the new behavior for your app on Android Q devices, even if your app is targeting API level 28 or lower.

The implementation details of these changes will be available with the Beta 3 release, but we wanted to share this update with you early, so you can better prepare your app for Android Q devices. Scoped Storage will be required in next year’s major platform release for all apps, independent of target SDK level, so we recommend you add support to your app well in advance. Please continue letting us know your feedback and how we can better align Scoped Storage with your app’s use cases. You can give us input through this survey, or file bugs and feature requests here.

Best practices for common feedback areas

Your feedback is incredibly valuable and has helped us shape these design decisions. We also want to take a moment to share some best practices for common questions we’ve heard:

  • Storing shared media files. For apps that handle files that users expect to be sharable with other apps (such as photos) and be retained after the app has been uninstalled, use the MediaStore API. There are specific collections for common media files: Audio, Video, and Images. For other file types, you can store them in the new Downloads collection. To access files from the Downloads collection, apps must use the system picker.
  • Storing app-internal files. If your app is designed to handle files not meant to be shared with other apps, store them in your package-specific directories. This helps keep files organized and limit file clutter as the OS will manage cleanup when the app is uninstalled. Calls to Context.getExternalFilesDir() will continue to work.
  • Working with permissions and file ownership. For MediaStore, no permissions are necessary for apps that only access their own files. Your app will need to request permission to access media contributed by other apps. However, if your app is uninstalled and then reinstalled later, you’ll need to request permission from the user in order to be able to access media your app previously contributed.
  • Working with native code or libraries. The recommended pattern is to begin your media file discovery in your Java-based or Kotlin-based code, then pass the file's associated file descriptor into your native code.
  • Working with many files efficiently. If you need to perform bulk file operations in a single transaction, consider using ContentProvider.applyBatch(). Learn more about ContentProvider batch processing here.
  • Integrating with the system file picker.
    • Documents apps, such as a word processor, can use the ACTION_OPEN_DOCUMENT or ACTION_GET_CONTENT action to open a system file picker. You can learn more about the differences here.
    • File management apps typically work with collections of apps in a directory hierarchy. Use ACTION_OPEN_DOCUMENT_TREE to let the user pick a directory subtree. The app can further manipulate files available in the returned directory. Through this support, users can access files from any installed DocumentsProvider instance, which can be supported by any cloud-based or locally-backed storage solutions.

We’ve also provided a detailed Scoped Storage developer guide with additional information.

What’s ahead

It’s been amazing to see the community engagement on Android Q Beta so far. As we finalize the release in the next several months, please continue testing and keep the feedback coming. Join us at Google I/O 2019 for more details on Scoped Storage and other Android Q features. We’re giving a ”What’s new on Shared Storage” talk on May 8, and you’ll be able to find the livestream and recorded video on the Google I/O site.