PreferenceScreen 得到CheckBoxPreference

final ListAdapter adapter = getPreferenceScreen().getRootAdapter();?
for (int idx = 0; idx < adapter.getCount(); idx++) {?
? ? Object object = adapter.getItem(idx);?
? ? if(object instanceof CheckBoxPreference){?
? ? ? ? ((CheckBoxPreference)object).setChecked(false);?
? ? }?
}?