SettingsActivity.java 文件源码

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

    if (preference instanceof ListPreference) {
        // For list preferences, look up the correct display value in
        // the preference's 'entries' list.
        ListPreference listPreference = (ListPreference) preference;
        int index = listPreference.findIndexOfValue(stringValue);

        // Set the summary to reflect the new value.
        preference.setSummary(
                index >= 0
                        ? listPreference.getEntries()[index]
                        : null);

    } else if (preference instanceof RingtonePreference) {
        // For ringtone preferences, look up the correct display value
        // using RingtoneManager.
        Ringtone ringtone = RingtoneManager.getRingtone(
                preference.getContext(), Uri.parse(stringValue));

        if (ringtone == null) {
            // Clear the summary if there was a lookup error.
            preference.setSummary(null);
        } else {
            // Set the summary to reflect the new ringtone display
            // name.
            String name = ringtone.getTitle(preference.getContext());
            preference.setSummary(name);
        }
    } else {
        // For all other preferences, set the summary to the value's
        // simple string representation.
        preference.setSummary(stringValue);
    }
    return true;
}