setup the CursorLoader SQLite CursorLoader in MainActivity

MainActivity.java

public class MainActivity extends AppCompatActivity implements  LoaderManager.LoaderCallbacks<Cursor> {

  private static final int URL_LOADER = 0;
  WordCursorAdapter mAdapter;

  // Define a projection that specifies which columns from the database
  // you will actually use after this query.
  String[] projection = {
    Words._ID,
    Words.COLUMN_WORD,
    Words.COLUMN_WORD_T,
    Words.COLUMN_WORD_T2};
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    getLoaderManager().initLoader(URL_LOADER, null, this);

    
    ListView wordList = findViewById(R.id.wordsListView);
    View emptyView = findViewById(R.id.empty_words_layout);
    wordList.setEmptyView(emptyView);

    mAdapter = new WordCursorAdapter(this, null);
    wordList.setAdapter(mAdapter);
  }
  
  @Override
  public Loader<Cursor> onCreateLoader(int loaderID, @Nullable Bundle bundle) {
    /*
      * Takes action based on the ID of the Loader that's being created
      */
    switch (loaderID) {
      case URL_LOADER:
        // Returns a new CursorLoader
        return new CursorLoader(
          MainActivity.this,   // Parent activity context
          ContractClass.CONTENT_URI,        // Table to query
          projection,     // Projection to return
          null,            // No selection clause
          null,            // No selection arguments
          null             // Default sort order
          );
      default:
        // An invalid id was passed in
        return null;
    }
  }

    @Override
    public void onLoadFinished(@NonNull Loader<Cursor> loader, Cursor cursor) {
        /*
         * Moves the query results into the adapter, causing the
         * ListView fronting this adapter to re-display
         */
        mAdapter.swapCursor(cursor);
    }

    @Override
    public void onLoaderReset(@NonNull Loader<Cursor> loader) {
        /*
         * Clears out the adapter's reference to the Cursor.
         * This prevents memory leaks.
         */
        mAdapter.changeCursor(null);
    }
  
}