How to sync ListView and Firebase Database?

Question

Android

Good afternoon,

There is a project that is tied to the Firebase Realtime Database. The data is loaded into the SharedPreference, then into the array of objects, and finally into the ListView. The task is not to connect to the Database every time, but to show the user data from the SharedPreference, but if there have been changes in the database (adding, changing, deleting), connect to the database, update the SharedPreference and show the user updated information. And if the user, say, has the Internet turned off, then he will have information, but not relevant.

My idea is to check the size of the SharedPreference at the start of the activity and compare it with the size of the Firebase Database, if different, then run the OnDataChanged method and update the SharedPreference.

Is the idea correct or should it be implemented differently. I would be grateful for any idea to solve the problem.

This is how it is currently implemented:

public class Dictionary extends AppCompatActivity {

    // Firebase db
    private DatabaseReference mDictionaryDatabase;

    // Android layout
    private ListView listViewDictionary;
    private List<DictionaryModel> arrayListDictionary;
    private DictionaryAdapter dictionaryAdapter;
    private SharedPreferences sPrefDictionary;
    String prefWord = "firebaseKey";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dictionary);


        mDictionaryDatabase = FirebaseDatabase.getInstance().getReference("dictionary");

        listViewDictionary = findViewById(R.id.listViewDictionary);
        arrayListDictionary = new ArrayList<>();

        sPrefDictionary = getSharedPreferences(prefWord, MODE_PRIVATE);


        mDictionaryDatabase.orderByChild("word").addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {


                for (DataSnapshot dictionarySnapshot : dataSnapshot.getChildren()){

                    DictionaryModel word = dictionarySnapshot.getValue(DictionaryModel.class);


                        SharedPreferences.Editor editor = sPrefDictionary.edit();
                        editor.putString(word.getWord(), word.getDescription()).apply();
                        dictionaryAdapter.notifyDataSetChanged();

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

            }
        });
        

        Map<String,?> keys = sPrefDictionary.getAll();
        for(Map.Entry<String,?> entry : keys.entrySet()){
            DictionaryModel dm = new DictionaryModel(entry.getKey(), entry.getValue().toString());
            arrayListDictionary.add(dm);
        }
        dictionaryAdapter = new DictionaryAdapter(Dictionary.this, arrayListDictionary);
        listViewDictionary.setAdapter(dictionaryAdapter);

    }