Question

我想在检查切换按钮上保存两个字符串值，然后从另一个Fragment中检索它。这就是我对按钮OnClickListener所做的，但它不起作用：

holder.favButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener(){
    @Override
    public void onCheckedChanged(CompoundButton favButton, boolean isChecked){
        if (isChecked)
            favButton.setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(),R.mipmap.ic_launcher));
        PreferenceManager.getDefaultSharedPreferences(context).edit().putString("PRODUCT_APP", "Product_Favorite").commit();

        else
            favButton.setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(), R.mipmap.ic_cart));
    }
});

这是我的SharedPreference班级

public class SharedPreference {

    public static final String PREFS_NAME = "PRODUCT_APP";
    public static final String FAVORITES = "Product_Favorite";

    public SharedPreference() {
        super();
    }

    // This four methods are used for maintaining favorites.
    public void saveFavorites(Context context, List<CardItemModel> favorites) {
        SharedPreferences settings;
        SharedPreferences.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, CardItemModel product) {
        List<CardItemModel> favorites = getFavorites(context);
        if (favorites == null)
            favorites = new ArrayList<CardItemModel>();
        favorites.add(product);
        saveFavorites(context, favorites);
    }

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

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

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

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

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

        return (ArrayList<CardItemModel>) favorites;
    }
}

Answer 1

让我们解决这个问题^^。 您可以在一个首选项中保存多个收藏夹，方法是在一个字符串中添加多个收藏夹，每个收藏项以逗号分隔。然后，您可以使用convertStringToArray方法将其转换为String Array。这是完整的源代码。使用MyUtility Methods保存多个喜欢的项目。

  MyUtility.addFavoriteItem(this, "Sports");
        MyUtility.addFavoriteItem(this, "Entertainment");

获取所有收藏夹保存的字符串数组

String[] favorites = MyUtility.getFavoriteList(this);// returns {"Sports","Entertainment"};

将这些方法保存在单独的Utility类

中

public abstract class MyUtility {

public static boolean addFavoriteItem(Activity activity,String favoriteItem){
    //Get previous favorite items
    String favoriteList = getStringFromPreferences(activity,null,"favorites");
    // Append new Favorite item
    if(favoriteList!=null){
        favoriteList = favoriteList+","+favoriteItem;
    }else{
        favoriteList = favoriteItem;
    }
    // Save in Shared Preferences
    return putStringInPreferences(activity,favoriteList,"favorites");
}
public static String[] getFavoriteList(Activity activity){
    String favoriteList = getStringFromPreferences(activity,null,"favorites");
    return convertStringToArray(favoriteList);
}
private static boolean putStringInPreferences(Activity activity,String nick,String key){
    SharedPreferences sharedPreferences = activity.getPreferences(Activity.MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString(key, nick);
    editor.commit();                        
    return true;        
}
private static String getStringFromPreferences(Activity activity,String defaultValue,String key){
    SharedPreferences sharedPreferences = activity.getPreferences(Activity.MODE_PRIVATE);
    String temp = sharedPreferences.getString(key, defaultValue);
    return temp;        
}

private static String[] convertStringToArray(String str){
    String[] arr = str.split(",");
    return arr;
}

}

如果您需要添加额外的收藏夹。然后从SharedPreference获取最喜欢的字符串并附加逗号+收藏项并将其保存回SharedPreference。 *您可以使用任何其他字符串作为分隔符而不是逗号。

如何使用SharedPreference存储字符串数组？

1 个答案: