CODEWITHSUNDEEP
androidandroid-roomandroid-livedata
deadpoint
deadpoint

Reputation: 453

Android Room return LiveData in Dao in a subscription

I have a room DAO with a find method which returns a LiveData.

In my Repository I want call that Dao method and return the LiveData object.

In my ViewModel I call the Repository for LiveData and so on..

My Dao:

@Query("SELECT * FROM user where userId = :userId)
LiveData<User> loadUser(String userId);

Now in my repository I call this Dao, but for userId I have to subscribe on a session.

public LiveData<User> loadUser() {
    session.getSubject().subscribe(session -> {
      db.getDb().userDao().loadUser(session.userId);
      //TODO: How I can return here my LiveData???
    });
}

How I could handle such a problem? How I could return this LiveData object in repository method.

Upvotes: 1

Views: 350

Answers (1)

Sanlok Lee
Sanlok Lee

Reputation: 3494

Try using MediatorLiveData like this:

public LiveData<User> loadUser() {
    MediatorLiveData<User> userLiveData = new MediatorLiveData<>();
    session.getSubject().subscribe(session -> {
        userLiveData.addSource(db.getDb().userDao().loadUser(session.userId), user -> {
            userLiveData.setValue(user);
        });
    });
    return userLiveData
}

Upvotes: 1

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