title: error: incompatible types: MainActivity cannot be converted to FragmentActivity .addPackage(new ReactDatePackage(this))
body: <p>I want to use this module <a href="https://github.com/nucleartux/react-native-date" rel="nofollow">https://github.com/nucleartux/react-native-date</a> for react-native. I trying to install this module, but when I do step 4 (Register React Package) I have an error with build.
  Error message: </p>
  
  <blockquote>
    <p>MainActivity.java:31: error: incompatible types: MainActivity cannot be converted to FragmentActivity
    .addPackage(new ReactDatePackage(this))
                                                     ^
    Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output
    1 error<br>
    :app:compileDebugJavaWithJavac FAILED<br>
    * What went wrong:
    Execution failed for task ':app:compileDebugJavaWithJavac'.
    Compilation failed.</p>
  </blockquote>
  
  <p>Code with error:</p>
  
  <pre><code>package com.myapp;
  
  import android.app.Activity;
  import android.os.Bundle;
  import android.view.KeyEvent;
  
  import com.facebook.react.LifecycleState;
  import com.facebook.react.ReactInstanceManager;
  import com.facebook.react.ReactRootView;
  import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
  import com.facebook.react.shell.MainReactPackage;
  import com.facebook.soloader.SoLoader;
  
  import me.nucleartux.date.ReactDatePackage;
  import android.support.v4.app.FragmentActivity;
  
  public class MainActivity extends Activity implements
  
  DefaultHardwareBackBtnHandler {
  
  private ReactInstanceManager mReactInstanceManager;
  private ReactRootView mReactRootView;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      mReactRootView = new ReactRootView(this);
  
      mReactInstanceManager = ReactInstanceManager.builder()
              .setApplication(getApplication())
              .setBundleAssetName("index.android.bundle")
              .setJSMainModuleName("index.android")
              .addPackage(new MainReactPackage())
              .addPackage(new ReactDatePackage(this))
              .setUseDeveloperSupport(BuildConfig.DEBUG)
              .setInitialLifecycleState(LifecycleState.RESUMED)
              .build();
  
      mReactRootView.startReactApplication(mReactInstanceManager, "myapp", null);
  
      setContentView(mReactRootView);
  }
  
  @Override
  public boolean onKeyUp(int keyCode, KeyEvent event) {
      if (keyCode == KeyEvent.KEYCODE_MENU &amp;&amp; mReactInstanceManager != null) {
          mReactInstanceManager.showDevOptionsDialog();
          return true;
      }
      return super.onKeyUp(keyCode, event);
  }
  
  @Override
  public void onBackPressed() {
    if (mReactInstanceManager != null) {
      mReactInstanceManager.onBackPressed();
    } else {
      super.onBackPressed();
    }
  }
  
  @Override
  public void invokeDefaultOnBackPressed() {
    super.onBackPressed();
  }
  
  @Override
  protected void onPause() {
      super.onPause();
  
      if (mReactInstanceManager != null) {
          mReactInstanceManager.onPause();
      }
  }
  
  @Override
  protected void onResume() {
      super.onResume();
  
      if (mReactInstanceManager != null) {
          mReactInstanceManager.onResume(this);
      }
  }
  }
  </code></pre>
  
  <p>Can you help me to fix this problem, please?</p>