android-app-multiprocess

Multi-process Android App with ObjectBox

This example shows how to use ObjectBox in a multi-process Android app written in Kotlin. The same principles apply for apps written in Java.

Note: this is NOT about multi-threading within an app process. Concurrency with multiple threads is covered in the transaction documentation.

When using ObjectBox with multiple processes, there should only be a single process that is writing to the database. All other processes should open the database in read-only mode.

About this example

• MainActivity runs in the main process of the app and uses a writable instance of the database.
• ReadProcessActivity runs in the :readonly process and uses a read-only instance of the database.
• ObjectBox provides a common singleton implementation (using double-checked locking) to get a BoxStore. ObjectBox.get(context) provides a writable database and ObjectBoxReadOnly.get(context) a read-only database.

Current limitations

Note that using the same database from multiple processes still has limitations, notably:

• The result of Box.count() is cached per process and so might not be as expected. Use Query.count() instead.
• Data observers are not notified if entities are changed in another process. For now, you need to set up your own inter-process notifications, e.g. by sending broadcasts.

Links

ObjectBox Docs

ObjectBox Homepage

ObjectBox Java/Kotlin GitHub repository