Обновление содержимого Recyclerview

package info.devbanha.smartwallet.activity;
 
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.TextView;
 
import java.util.ArrayList;
import java.util.List;
 
import info.devbanha.smartwallet.R;
import info.devbanha.smartwallet.adapters.RecyclerViewAdapter;
import info.devbanha.smartwallet.data.ItemData;
import info.devbanha.smartwallet.data.database.DataBaseController;
import info.devbanha.smartwallet.data.database.ItemDB;
import info.devbanha.smartwallet.tag.Tags;
 
public class MainActivity extends AppCompatActivity {
 
    private TextView textView;
    private RecyclerViewAdapter recyclerViewAdapter;
    private DataBaseController db;
    private Tags tag = new Tags();
    private List<ItemData> itemData = new ArrayList<>();
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        textView = (TextView) findViewById(R.id.textViewAnim);
 
        db = new DataBaseController(this, tag.NAME_DB(), null, tag.VERSION_DB());
 
        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
 
        recyclerViewAdapter = new RecyclerViewAdapter(getItemData());
        recyclerView.setLayoutManager(linearLayoutManager);
 
        List<ItemDB> itemDBs = db.getAllItems();
        for (ItemDB it : itemDBs) {
            addData(it.getDbName(), it.getDbPrice(), it.getDbComment());
        }
 
        recyclerView.setAdapter(recyclerViewAdapter);
 
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
    }
 
    private void deleteDB() {
        db.deleteAll();
    }
 
    public void addData(String name, Double price, String category) {
        itemData.add(new ItemData(name, price, category));
    }
 
    public List<ItemData> getItemData() {
        return itemData;
    }
 
    @Override
    protected void onResume() {
        super.onResume();
        Log.i(tag.MAIN_ACTIVITY_TAG(), "onResume");
        recyclerViewAdapter.notifyDataSetChanged();
    }
 
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }
 
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.action_settings:
                deleteDB();
                Log.i(tag.MAIN_ACTIVITY_TAG(), "action settings");
                recyclerViewAdapter.notifyDataSetChanged();
                break;
        }
        return super.onOptionsItemSelected(item);
    }
 
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.fab:
                Intent intent = new Intent(this, InputActivity.class);
                startActivity(intent);
                break;
            case R.id.textViewAnim:
                Animation anim;
                anim = AnimationUtils.loadAnimation(this, R.anim.anim_alpha);
                textView.startAnimation(anim);
                break;
        }
    }
}