android studio Deficiencies in the project

1-) Check if the user is logged in MainActivity. If the user has not logged in, the loginfragment will not be able to enter other fragments. 2-) In LoginFragment, I do logon and logoff with firebase with Google. 3-) Login verification is done in LoginFragment. Firebase login and logout with Facebook. 4-) The application will run on the backplane like WhatApp. Firebase will continue to send and receive data. 5-) Every user has his own sub-user. I am adding a table sub users to Firebase. But each user should see their own sub-user. He will not see the sub-users of other users. 6-) I'm notifying all users that I've contacted Onesignal. But I want to send sub-users whose tags are specific. Operations with TeamViewer will be done remotely on my computer. Your labor will certainly be provided.