title: Cannot resolve symbol ViewModelProviders on AppCompatActivity
body: <p>Hey I'm trying to get my ViewModel working, but no luck so far. 
  Android Studio shows error <code>Cannot resolve symbol 'ViewModelProviders'</code>. </p>
  
  <p>Every other question I found on this topic was correcting <code>extends Activity</code> to <code>extends AppCompatActivity</code>, but I am extending the right one. Not sure what I'm missing...<br>
  My code is based on <a href="https://youtu.be/c9-057jC1ZA" rel="noreferrer">This YouTube video</a></p>
  
  <p><strong>MainActivity.java</strong> </p>
  
  <pre><code>public class MainActivity extends AppCompatActivity implements
      TileAdapter.TileAdapterOnClickHandler {
  
  
  private BaseViewModel viewModel;
  
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      //set Toolbar
      Toolbar myToolbar = findViewById(R.id.toolbar);
      setSupportActionBar(myToolbar);
  
  
      //initialize viewModel
      viewModel = ViewModelProviders.of(this).get(BaseViewModel.class);
  </code></pre>
  
  <p><strong>BaseViewModel.java</strong></p>
  
  <pre><code>public class BaseViewModel extends ViewModel {
  
  private Movie[] mMovie;
  
  public void init (Movie[] movies){
      this.mMovie = movies;
  }
  
  public Movie[] getMovie() {
      return mMovie;
  }
  </code></pre>