SettingsActivity.java 文件源码

@Override
public boolean onPreferenceChange(Preference preference, Object value) {
    String stringValue = value.toString();

    if (preference instanceof ListPreference) {
        ListPreference listPreference = (ListPreference) preference;
        int index = listPreference.findIndexOfValue(stringValue);
        preference.setSummary(
                index >= 0
                        ? listPreference.getEntries()[index]
                        : null);

    } else if (preference instanceof RingtonePreference) {
        if (TextUtils.isEmpty(stringValue)) {
            preference.setSummary("Silent");
        } else {
            Ringtone ringtone = RingtoneManager.getRingtone(
                    preference.getContext(), Uri.parse(stringValue));

            if (ringtone == null) {
                preference.setSummary(null);
            } else {
                String name = ringtone.getTitle(preference.getContext());
                preference.setSummary(name);
            }
        }
    } else {
        preference.setSummary(stringValue);
    }
    return true;
}