How to get all data from room table in android using async Task in a List

Issue

I want to get List<Model> from Room database in Android without using LiveData. How to get all the rows using asynctask or thread function.

Solution

First define get method in your DAO, consider you are getting all Users:

UserModel:

@Entity
public class UserModel {
    @PrimaryKey
    public int id;

    public String first_name;
    public String last_name;
}

User Data Access Object

@Dao
public interface UserDao {
    @Query("SELECT first_name, last_name FROM user")
    public List<UserModel> getAllUsers();
}

Create you application db wrapper class

@Database(entities = {UserModel.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {
    public abstract UserDao userDao();
}

get access to db use following code

public class UserServices{

        private AppDatabase db ;

        public UserServices(){
            db = Room.databaseBuilder(getApplicationContext(),
                    AppDatabase.class, "database-name").build();
        }

        public List<UserModel> getAllUsers(){
            return new GetUsersAsyncTask().exicute().get();
        }


        private class GetUsersAsyncTask extends AsyncTask<Void, Void,List<UserModel>> 
        {
            @Override
            protected Void doInBackground(Void... url) {
                return db.getUserDao().getAllUsers();
            }
        }
    }

Now access Users by calling

UserServices userServices=new UserServices();
List<UserModel> users=userServices.getAllUsers();

Answered By - Geo