title: Changing fragment from Navigation drawer
body: <p>I am basically having the exact same problem as OP here: <a href="https://stackoverflow.com/questions/20638967/how-to-change-fragments-using-android-navigation-drawer/20639340#20639340">How to change fragments using Android navigation drawer</a></p>
  
  <p>Also using the Template for an navigation drawer activity in Android Studio.</p>
  
  <p>I tried Dreagan's answer, but I am now stuck with a cycle of errors.</p>
  
  <p>Here is my code</p>
  
  <pre><code>import android.app.Activity;
  import android.app.ActionBar;
  import android.app.Fragment;
  import android.app.FragmentManager;
  import android.app.FragmentTransaction;
  import android.content.Context;
  import android.os.Build;
  import android.os.Bundle;
  import android.view.Gravity;
  import android.view.LayoutInflater;
  import android.view.Menu;
  import android.view.MenuItem;
  import android.view.View;
  import android.view.ViewGroup;
  import android.support.v4.widget.DrawerLayout;
  import android.widget.ArrayAdapter;
  import android.widget.TextView;
  
  
  public   class MainActivity extends Activity
          implements NavigationDrawerFragment.NavigationDrawerCallbacks {
  
      /**
       * Fragment managing the behaviors, interactions and presentation of the navigation drawer.
       */
      private NavigationDrawerFragment mNavigationDrawerFragment;
  
      /**
       * Used to store the last screen title. For use in {@link #restoreActionBar()}.
       */
      private CharSequence mTitle;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          mNavigationDrawerFragment = (NavigationDrawerFragment)
                  getFragmentManager().findFragmentById(R.id.navigation_drawer);
          mTitle = getTitle();
  
          // Set up the drawer.
          mNavigationDrawerFragment.setUp(
                  R.id.navigation_drawer,
                  (DrawerLayout) findViewById(R.id.drawer_layout));
      }
  
      @Override
      public void onNavigationDrawerItemSelected(int position) {
          // update the main content by replacing fragments
  
          Fragment fragment = new NewsfeedFragment();
          FragmentManager fragmentManager = getFragmentManager();
  
          Bundle args = new Bundle();
          args.putInt(NewsfeedFragment.ARG_PLANET_NUMBER, position);
          fragment.setArguments(args);
  
          switch(position){
              case 0:
                  fragment = new NewsfeedFragment();
  
                  break;
  
              case 1:
                  fragment = new NewsfeedFragment();
                  break;
          }
          fragmentManager.beginTransaction()
                  .replace(R.id.container, fragment)
                  .commit();
      }
  
      public void onSectionAttached(int number) {
  
          switch (number) {
              case 1:
                  mTitle = getString(R.string.title_section1);
                  break;
  
              case 2:
                  mTitle = getString(R.string.title_section2);
                  break;
  
              case 3:
                  mTitle = getString(R.string.title_section3);
                  break;
          }
      }
  
      public void restoreActionBar() {
          ActionBar actionBar = getActionBar();
          actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
          actionBar.setDisplayShowTitleEnabled(true);
          actionBar.setTitle(mTitle);
      }
  
  
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
          if (!mNavigationDrawerFragment.isDrawerOpen()) {
              // Only show items in the action bar relevant to this screen
              // if the drawer is not showing. Otherwise, let the drawer
              // decide what to show in the action bar.
              getMenuInflater().inflate(R.menu.main, menu);
              restoreActionBar();
              return true;
          }
          return super.onCreateOptionsMenu(menu);
      }
  
      @Override
      public boolean onOptionsItemSelected(MenuItem item) {
          // Handle action bar item clicks here. The action bar will
          // automatically handle clicks on the Home/Up button, so long
          // as you specify a parent activity in AndroidManifest.xml.
          int id = item.getItemId();
  
          //noinspection SimplifiableIfStatement
          if (id == R.id.action_settings) {
              return true;
          }
  
          return super.onOptionsItemSelected(item);
      }
  
      /**
       * A placeholder fragment containing a simple view.
       */
      public static class PlaceholderFragment extends Fragment {
          /**
           * The fragment argument representing the section number for this
           * fragment.
           */
          private static final String ARG_SECTION_NUMBER = "section_number";
  
          /**
           * Returns a new instance of this fragment for the given section
           * number.
           */
          public static PlaceholderFragment newInstance(int sectionNumber) {
              PlaceholderFragment fragment = new PlaceholderFragment();
              Bundle args = new Bundle();
              args.putInt(ARG_SECTION_NUMBER, sectionNumber);
              fragment.setArguments(args);
              return fragment;
          }
  
          public PlaceholderFragment() {
          }
  
          @Override
          public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                   Bundle savedInstanceState) {
              View rootView = inflater.inflate(R.layout.fragment_main, container, false);
              return rootView;
          }
  
          @Override
          public void onAttach(Activity activity) {
              super.onAttach(activity);
              ((MainActivity) activity).onSectionAttached(
                      getArguments().getInt(ARG_SECTION_NUMBER));
          }
      }
  
  }
  </code></pre>
  
  <p>If I run the code as it is here I get following error:</p>
  
  <pre><code>java.lang.RuntimeException: Unable to start activity ComponentInfo{dk.gruppe2.jammerbugtevent/dk.gruppe2.jammerbugtevent.MainActivity}: java.lang.ClassCastException: dk.gruppe2.jammerbugtevent.MainActivity@429e4a70 must implement OnFragmentInteractionListener
  </code></pre>
  
  <p>When I implement <code>OnFragmentInteractionListener</code>, I get the following error:</p>
  
  <pre><code>Error:(22, 9) error: MainActivity is not abstract and does not override abstract method onFragmentInteraction(Uri) in OnFragmentInteractionListener
  </code></pre>
  
  <p>When i declare <code>MainActivity</code> as abstract, i get this error:</p>
  
  <pre><code>    java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{dk.gruppe2.jammerbugtevent/dk.gruppe2.jammerbugtevent.MainActivity}: java.lang.InstantiationException: can't instantiate class dk.gruppe2.jammerbugtevent.MainActivity
  </code></pre>
  
  <p>I am very new to android, and not exactly an expert regarding programming to begin with. Any help would be much appreciated. Thanks In advance.</p>