PreferenceFragment.java 文件源码

/**
 * Inflates the given XML resource and replaces the current preference hierarchy (if any) with
 * the preference hierarchy rooted at {@code key}.
 *
 * @param preferencesResId The XML resource ID to inflate.
 * @param key The preference key of the {@link PreferenceScreen} to use as the root of the
 *            preference hierarchy, or null to use the root {@link PreferenceScreen}.
 */
public void setPreferencesFromResource(@XmlRes int preferencesResId, @Nullable String key) {
    requirePreferenceManager();

    final PreferenceScreen xmlRoot = mPreferenceManager.inflateFromResource(mStyledContext,
            preferencesResId, null);

    final Preference root;
    if (key != null) {
        root = xmlRoot.findPreference(key);
        if (!(root instanceof PreferenceScreen)) {
            throw new IllegalArgumentException("Preference object with key " + key
                    + " is not a PreferenceScreen");
        }
    } else {
        root = xmlRoot;
    }

    setPreferenceScreen((PreferenceScreen) root);
}