更改首选项主题

Question

我已经在Implementing user choice of theme中尝试了答案，但它对我不起作用。

我的设置中有一个列表首选项，允许用户在浅色或深色主题之间进行选择。我该怎么办？这是我在“设置活动”中的OnPreferenceChangeListener，我是从互联网上学到的。

private static Preference.OnPreferenceChangeListener themelistener = new Preference.OnPreferenceChangeListener() {
    @Override
    public boolean onPreferenceChange(Preference preference, Object newValue) {
        String stringValue = newValue.toString();

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

            if (index == 0) {
                Toast.makeText(thisActivity, "Dark" , Toast.LENGTH_SHORT).show();MainActivity.reloadTheme();     //if done toast will be deleted
            } else if (index == 1){Toast.makeText(thisActivity, "Light" , Toast.LENGTH_SHORT).show();MainActivity.reloadTheme();
            }
            return true;
        }
        return true;
    }
    ;
};

修改 我的MainActivity代码段有问题，无法解析themeId

public static void reloadTheme()
{
    int index = PreferenceManager.getDefaultSharedPreferences(thisActivity).getInt("index", 0);
    if(index == 0){  //couldn't resolve themeId
        themeId = R.style.OwnDark; 
    }
    else if(index == 1){
        themeId = R.style.OwnLight;
    }
}