MainActivity.java

public class MainActivity extends AppCompatActivity implements MainActivityView {

  @BindView(R.id.lv_am_movie_list) ListView listView;
  @BindView(R.id.pb_am_loading) ProgressBar progressBar;
  public static MainPresenter mainPresenter;

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

    ButterKnife.bind(this);
    listView.setVisibility(View.GONE);
    progressBar.setVisibility(View.VISIBLE);

    if (mainPresenter == null) {
      mainPresenter = new MainPresenter();
    }
    mainPresenter.attachView(this);
  }

  @Override protected void onDestroy() {
    super.onDestroy();
    mainPresenter.detachView();
    if (isFinishing()) mainPresenter = null;
  }

  @Override public Context getAppContext() {
    return getApplicationContext();
  }

  @Override public Context getActivityContext() {
    return this;
  }

  @Override public ListView getListView() {
    return listView;
  }

  @Override public ProgressBar getProgressBar() {
    return progressBar;
  }
}

Thanks for your demonstrate.

Why do you add if(isFinishing()) on onDestroy() method?