Room provides an abstraction layer over SQLite to allow fluent database access while harnessing the full power of SQLite.
There are 3 major components in Room:
- Database
- Entity
- Dao
Very basic usages and setup of room data base has been shown via user example.
Basic crucks-
*. Setup of data base
AppDatabase - create db
@Database(entities = {User.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {
appDatabase = Room.databaseBuilder(context.getApplicationContext(),
AppDatabase.class, "database-name").build();
*. UserDao - interface to provide access on db-
@Dao
public interface UserDao {
@Query("SELECT * FROM user")
List<User> getAll();
//init service
*. Initilize service where you want to use room db-
private UserServiceImpl userService;
userService = new UserServiceImpl(LoginActivity.this);
*. From do in background save objects in db
User user = new User();
user.setUid(new Random().nextInt());
user.setEmail(mEmail);
user.setPassword(mPassword);
user.setFirstName("First Name");
user.setLastName("Last Name");
userService.insertAll(user);
users = userService.getAll();
*. Simple method to get db in background thread and showing data on UI-
private void getUsersFromDB() {
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
users = userService.getAll();
return null;
}
@Override
protected void onPostExecute(Void agentsCount) {
usersTextView.setText("Users \n\n " + users);
}
}.execute();
