如何从首选项屏幕打开AlertDialog？

PreferenceActivity

onSharedPreferenceChanged

public class MyPreferences extends PreferenceActivity implements OnSharedPreferenceChangeListener {
    ...
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
        if (key.equals(\"MyCheckboxPreferenceKey\")) {
            //Show your AlertDialog here!
        }
    }

public class MyPreferences extends PreferenceActivity implements OnSharedPreferenceChangeListener {

      public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
                final Preference preference) {

         if(preference.equals(\"MyCheckboxPreferenceKey\")) {

             AlertDialog.Builder builder = new AlertDialog.Builder(this);

         builder.setMessage(\"Your Message\");

         builder.setPositiveButton(\"OK\", new DialogInterface.OnClickListener() {

           public void onClick(DialogInterface dialog, int id) {

             //action on dialog close
           }

         });

         builder.show();

      }


}

public class MyPreferences extends PreferenceActivity{
 ...
//getting current context for builder
AlertDialog.Builder build = new AlertDialog.Builder(this);
//setting some title text
build.setTitle(\"SomeTitle\");
//setting radiobuttons list
build.setSingleChoiceItems(new String[]{\"One\", \"Two\"}, 0, new OnClickListener() {                               

            @Override
            public void onClick(DialogInterface dialog, int which) {
                //Some behavior here    
            }
        });
        build.setNegativeButton(\"Cancel\", new OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                //Might be empty
            }
        });
                    //creating dialog and showing
        AlertDialog dialog = build.create();
        dialog.show();
}