java.lang.IllegalStateException: FirebaseApp with name [DEFAULT]

Question

I have been getting this issue.. followed the upgrade guide for new firebase sdk...saved the google services json file in app directory.. still the same error as you but for

Answer 1

I solved this error by don't put anything of Firebase in Application. I put it in to MainActivity. Example: MainActivity.java

@Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    FirebaseDatabase.getInstance().setPersistenceEnabled(true);
    ...
}

-UPDATE

Other solution is create a DatabaseHelper class contain one FirebaseDatabase instance.

public class DatabaseHelper {
  private static boolean persistenceEnable = false;
  private static FirebaseDatabase mDatabase;


  public static boolean isPersistenceEnable(){
    return persistenceEnable;
  }
  public static FirebaseDatabase getInstance() {
    if (mDatabase == null) {
      mDatabase = FirebaseDatabase.getInstance();
      if(persistenceEnable==true) {
        mDatabase.setPersistenceEnabled(true);
      }
    }

    return mDatabase;
  }
}

and using by: FirebaseDatabase database = DatabaseHelper.getInstance();