Sync device contact list with Firebase using MVVM (Android Architecture Components)

问题

I've always used the structure below to identify whether a user has an account in my app.

All of this code is placed in MainActivity, but Google Architecture Components suggests to separate UI from the back-end logic.

I've followed the example below for integrating the contact list with MVVM structure.

https://github.com/NaarGes/Android-Contact-List

But I don't know how to insert the Firebase Realtime Database validation.

private void getContactList(){

    Cursor phones = getContext().getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,null,null,null);

    while (phones.moveToNext()){
        String name = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
        String phone = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

        phone = phone.replace(" ","");
        phone = phone.replace("-","");
        phone = phone.replace("(","");
        phone = phone.replace(")","");

        UserObject mContact = new UserObject("",name, phone);
        contactList.add(mContact);
        getUserDetails(mContact);
    }
}

private void getUserDetails(UserObject mContact) {
    DatabaseReference mUserDB = FirebaseDatabase.getInstance().getReference().child("user");
    // Only lists the users that have an account in the app into Firebase
    Query query = mUserDB.orderByChild("phone").equalTo(mContact.getPhone());
    query.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            if (dataSnapshot.exists()) {
                String uid, name = "", phone = "", email, image;

                for (DataSnapshot childSnapshot : dataSnapshot.getChildren()){
                    uid = childSnapshot.getKey().toString();
                    if (childSnapshot.child("phone").getValue() != null) {
                        phone = childSnapshot.child("phone").getValue().toString();
                    }
                    if (childSnapshot.child("name").getValue() != null) {
                        name = childSnapshot.child("name").getValue().toString();
                    }
                    email = childSnapshot.child("email").getValue().toString();
                    image = childSnapshot.child("image").getValue().toString();

                    UserObject mUser = new UserObject(childSnapshot.getKey(), name, phone);
                    mUser.setImageUrl(image);

                    if (name.equals(phone)) {
                        for (UserObject mContactIterator : contactList) {
                            if (mContactIterator.getPhone().equals(mUser.getPhone())) {
                                mUser.setName(mContactIterator.getName());
                            }
                        }
                    }


                    return;
                }
            }
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });
}

My question is: How to convert the code above into MVVM (Android Architecture Components)?

Thanks in advance!

来源：https://stackoverflow.com/questions/57317023/sync-device-contact-list-with-firebase-using-mvvm-android-architecture-componen