java - 如何从 RecyclerView Adapter 中的 Sharedpreferences 获取数据并传递到下一个 fragment

Question

尝试将共享首选项中的数据获取到 recylerview 适配器中，但我收到 context = null。我还在适配器中初始化了上下文。我搜索了很多，但没有任何帮助。任何教程或任何帮助将不胜感激

这是我的适配器:-

    public class HomeFeaturedAdapter extends RecyclerView.Adapter<HomeFeaturedAdapter.HomeViewHolder> {

    Context context;

    public HomeFeaturedAdapter(List<Products> productList) {

        this.context = context;
    }



    @NonNull
    @Override
    public HomeViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.brand_adapter_row, parent, false);
        return new HomeViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull HomeViewHolder homeViewHolder, int i) {

        SharedPreferences preferences = context.getSharedPreferences("MyPref", MODE_PRIVATE);
        String imageload = preferences.getString("permalink", null);

        /*SharedPreferences sharedPrefs = ((HomeViewHolder) homeViewHolder).imageload.getContext().getSharedPreferences("MyData", Context.MODE_PRIVATE);*/

        /*SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(MainActivity.context);
        String imageload = sharedPreferences.getString("permalink", null);*/


        if (imageload != null) {

            Picasso.with(context).load(imageload).fit().into(homeViewHolder.imagesViews);

        }

/*
        homeViewHolder.view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                AppCompatActivity activity = (AppCompatActivity) view.getContext();
                Fragment myFragment = new ProductDetailsFragment();
                activity.getSupportFragmentManager().beginTransaction().replace(R.id.mainfraime, myFragment).addToBackStack(null).commit();
            }
        });
*/

    }

    @Override
    public int getItemCount() {
        return 10;
    }

    public class HomeViewHolder extends RecyclerView.ViewHolder {

        public View view;
        TextView productTitle;
        ImageView imagesViews;
        CardView brandCardview;

        public HomeViewHolder(@NonNull View itemView) {
            super(itemView);
            this.view = itemView;

            productTitle = itemView.findViewById(R.id.productTitle);
            imagesViews = itemView.findViewById(R.id.imagesViews);
            brandCardview = itemView.findViewById(R.id.brandCardview);
        }
    }
}

如果我像这样在构造函数中添加上下文

` 

    public HomeFeaturedAdapter(Context context, List<Products> productList) {

            this.context = context;
        }

`

我的 Home Fragment 错误:类 HomeFeaturedAdapter 中的构造函数 HomeFeaturedAdapter 无法应用于给定类型；
HomeFeaturedAdapter 适配器 = new HomeFeaturedAdapter(productList);

请帮助我找到一个解决方案，我在谷歌上尝试了很多，但不明白该怎么做。

Answer 1

您已将 Context 添加到适配器构造函数中，因此当您从 fragment 或 Activity 中调用此构造函数时，您需要添加上下文。如果您从 Activity 调用中调用它

 HomeFeaturedAdapter adapter = new HomeFeaturedAdapter(this, productList)

您可以从 Fragment 中调用

HomeFeaturedAdapter adapter = new HomeFeaturedAdapter(getActivity(), productList)