PreferenceManager.setDefaultValues(this, R.xml.preference01, false);
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);

String str = prefs.getString(key, defValue); 

EditTextPreference et_pre_restaurant;

et_pre_restaurant =  (EditTextPreference)findPreference("name_restaurant");

et_pre_restaurant.setOnPreferenceChangeListener(this);

EditTextPreference et_pre_restaurant;

et_pre_restaurant =  (EditTextPreference)findPreference("name_restaurant");

preTimeSleep01.setSummary("hello");

    @Override
public boolean onPreferenceChange(Preference preference, Object object) {
// TODO Auto-generated method stub
        
if (preference.getKey().equals("name_restaurant")){

            Toast.makeText(SystemSetActivity.this, "餐厅名称修改了", Toast.LENGTH_SHORT).show();
        }
return true;
    }