How to populate Android Room database table on first run?

Question

In SQLiteOpenHelper there is a onCreate(SQLiteDatabase ...) method which i used to populate database tables with some initial data.

Answer 1

I tried to use the RoomDatabase.Callback as suggested by Arnav Rao, but to use a callback you cannot use the DAO as the callback is created before the database has been built. You could use db.insert and content values, but I didn't think that would have been correct. So after looking into it a bit more - took me ages lol - but I actually found the answer when going through the samples provided by Google.

https://github.com/googlesamples/android-architecture-components/blob/master/PersistenceContentProviderSample/app/src/main/java/com/example/android/contentprovidersample/data/SampleDatabase.java

See line 52 and the method on line 71 - In there you can see after the build of the database instance, the next line calls a method which checks if there are any records in the database (using the DAO) and then if it’s empty it inserts the initial data (again using the DAO).

Hope this helps anyone else who was stuck :)