title: Android Start Preference Activity Intent results in Exception
body: <p>i have a problem, i want to run an activity which handles a preference dialog</p>
  
  <pre><code>Intent i= new Intent(getBaseContext(), PreferencesActivity.class);
              startActivity(i);
  </code></pre>
  
  <p>when i run the app i only get an nullpointerexcepltion when the activity should start. what is wrong?</p>
  
  <p>PreferencesActivity looks this way: </p>
  
  <pre><code>import android.app.Activity;
  import android.content.SharedPreferences;
  import android.os.Bundle;
  import android.preference.Preference;
  import android.preference.PreferenceActivity;
  import android.preference.Preference.OnPreferenceClickListener;
  import android.widget.Toast;
  
  public class PreferencesActivity extends PreferenceActivity {
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          addPreferencesFromResource(R.layout.preferences);
          // Get the custom preference
          Preference customPref = (Preference) findPreference("customPref");
          customPref.setOnPreferenceClickListener(new OnPreferenceClickListener() {
  
               public boolean onPreferenceClick(Preference preference) {
                   Toast.makeText(getBaseContext(),
                       "The custom preference has been clicked",
                       Toast.LENGTH_LONG).show();
                   SharedPreferences customSharedPreference = getSharedPreferences(
                       "myCustomSharedPrefs", Activity.MODE_PRIVATE);
                   SharedPreferences.Editor editor = customSharedPreference.edit();
                   editor.putString("myCustomPref","The preference has been clicked");
                   editor.commit();
                   return true;
              }
          });
      }
  }
  </code></pre>