SettingsManager.java 文件源码

/**
 * Add an OnSettingChangedListener to the SettingsManager, which will
 * execute onSettingsChanged when any SharedPreference has been updated.
 */
public void addListener(final OnSettingChangedListener listener) {
    if (listener == null) {
        throw new IllegalArgumentException("OnSettingChangedListener cannot be null.");
    }

    if (mListeners.contains(listener)) {
        return;
    }

    mListeners.add(listener);
    OnSharedPreferenceChangeListener sharedPreferenceListener =
            getSharedPreferenceListener(listener);
    mSharedPreferenceListeners.add(sharedPreferenceListener);
    mDefaultPreferences.registerOnSharedPreferenceChangeListener(sharedPreferenceListener);

    if (mCustomPreferences != null) {
        mCustomPreferences.registerOnSharedPreferenceChangeListener(
            sharedPreferenceListener);
    }
    Log.v(TAG, "listeners: " + mListeners);
}