限制存储在共享首选项中的列表项的数量

Question

我在listview项目中有一个listview和一个按钮，当按下时，通过将列表项转换为JSON，将partucular listitem添加到我的共享首选项中。 一切正常但我想限制添加到共享偏好的列表项目的数量说只有5个列表项目被添加到共享首选项中，如果添加了第6个列表项目，它应该替换已添加的第1个列表项目。

这可能吗？

这是我的sharedpreference.java

public class SharedPreference
{

public static final String PREFS_NAME = "MY__APP"
public static final String FAVORITES = "app_Favorite";

public SharedPreference(){
    super();
}

public void saveFavorites(Context context, List<CodeList> favorites){
    SharedPreferences settings;
    Editor editor;

    settings = context.getSharedPreferences(PREFS_NAME,
                                            Context.MODE_PRIVATE);
    editor = settings.edit();

    Gson gson = new Gson();
    String jsonFavorites = gson.toJson(favorites);

    editor.putString(FAVORITES, jsonFavorites);

    editor.commit();
}

public void addFavorite(Context context, CodeList code){
    List<CodeList> favorites = getFavorites(context);

    if(favorites == null)
        favorites = new ArrayList<CodeList>();
    favorites.add(code);
    saveFavorites(context,favorites);
}

public void removeFavorite(Context context, CodeList code) {
    ArrayList<CodeList> favorites = getFavorites(context);
    if (favorites != null) {
        favorites.remove(code);
        saveFavorites(context, favorites);
    }
}


public ArrayList<CodeList> getFavorites(Context context) {
    SharedPreferences settings;
    List<CodeList> favorites;
    //ArrayList<CodeList> favorites;

    settings = context.getSharedPreferences(PREFS_NAME,
                                            Context.MODE_PRIVATE);

    if (settings.contains(FAVORITES)) {
        String jsonFavorites = settings.getString(FAVORITES, null);
        Gson gson = new Gson();
        CodeList[] favoriteItems = gson.fromJson(jsonFavorites,
                                                 CodeList[].class);

        favorites = Arrays.asList(favoriteItems);
        favorites = new ArrayList<CodeList>(favorites);
        //favorites  = new ArrayList<CodeList>();
      //favorites.addAll(Arrays.asList(favoriteItems));
    } else
        return null;

    return (ArrayList<CodeList>) favorites;
    //return favorites;
}

}