How to use Room Persistence Library with pre-populated database?

Question

I\'d like to use Room with a pre-populated database, but I can\'t understand how to tell Room where to find my database.

I\'ve now put it in src/main/assets/da

Answer 1

This is how I solved it, and how you can ship your application with a pre-populated database (up to Room v. alpha5)

• put your SQLite DB database_name.db into the assets/databases folder

• take the files from this repo and put them in a package called i.e. sqlAsset

• in your AppDatabase class, modify your Room's DB creation code accordingly:

  Room.databaseBuilder(context.getApplicationContext(), 
                       AppDatabase.class, 
                       "database_name.db")
  .openHelperFactory(new AssetSQLiteOpenHelperFactory())
  .allowMainThreadQueries()
  .build();
  

Note that you have to use "database_name.db" and not getDatabasePath() or other methods: it just needs the name of the file.

Answer 2

I was having the same problem so I created a library which does exactly that. the accepted answer work but I think it's easier to use a library.

AppDatabase db = RoomAsset
    .databaseBuilder(context.getApplicationContext(), AppDatabase.class, "database_name.db")
    .build(); 

Add it to your root build.gradle at the end of repositories:

allprojects {
    repositories {
        ...
        maven { url "https://jitpack.io" }
    }
}

Add the dependency

dependencies {
    // ... other dependencies
    implementation 'com.github.humazed:RoomAsset:v1.0'
}

you can find the library here: https://github.com/humazed/RoomAsset