title: Android action bar home button
body: <p>I've set my action bar like so but nothing happens when I click the home up button. 
  The two options below are enabled so shouldn't it go to the home activity automatically?</p>
  
  <pre><code>ab.setHomeButtonEnabled(true);
  ab.setDisplayHomeAsUpEnabled(true);
  </code></pre>
  
  <p><strong>Action Bar</strong></p>
  
  <pre><code>@Override
  public boolean onCreateOptionsMenu(Menu menu) {
      MenuInflater inflater = getMenuInflater();
      inflater.inflate(R.menu.menu, menu);
  
      final String[] activities;
      Resources res = getResources();
      activities =  res.getStringArray(R.array.activities);
  
      ActionBar ab = getActionBar();
      ab.setHomeButtonEnabled(true);
      ab.setDisplayHomeAsUpEnabled(true);
      ab.setTitle(R.string.app_name);
      ab.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
      ab.show();
  
      /** Create an array adapter to populate dropdownlist */
      ArrayAdapter&lt;String&gt; adapter = new ArrayAdapter&lt;String&gt;(getBaseContext(), android.R.layout.simple_spinner_dropdown_item, activities);
  
      /** Setting dropdown items and item navigation listener for the actionbar */
      getActionBar().setListNavigationCallbacks(adapter, navigationListener);
  
      /** Enabling dropdown list navigation for the action bar */
      getActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
      return true;
  }
  </code></pre>