毕加索 - 找不到 "context"

Question

首先，我是初学者，这对你来说可能是个愚蠢的问题。 我需要将上下文传递给以下代码，以便在 recyclerview 中加载图像。尝试了几个选项，但没有一个成功。我的问题是如何找到要在以下代码中传递的上下文。

Picasso.with(context here).load("http://i.imgur.com/DvpvklR.png").into(thumbnail);

这是导致问题的完整代码（我正在尝试将图像传递给 recyclerview）

public class WishListAdapter extends RecyclerView.Adapter<WishListAdapter.DerpHolder> {

    private List<WishListItem> listData;
    private LayoutInflater inflater;

    public WishListAdapter(List<WishListItem> listData, Context c) {
        inflater = LayoutInflater.from(c);
        this.listData = listData;
    }

    @Override
    public WishListAdapter.DerpHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.wish_list_item, parent, false);
        return new DerpHolder(view);
    }

    @Override
    public void onBindViewHolder(DerpHolder holder, int position) {

    }

    public void setListData(ArrayList<WishListItem> exerciseList) {
        this.listData.clear();
        this.listData.addAll(exerciseList);
    }

    @Override
    public int getItemCount() {
        return listData.size();
    }

    class DerpHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        ImageView thumbnail;
        TextView title;
        TextView subTitle;
        View container;


        public DerpHolder(View itemView) {
            super(itemView);
            thumbnail = itemView.findViewById(R.id.im_item_icon);

            //subTitle = itemView.findViewById(R.id.lbl_item_sub_title);

            //title = itemView.findViewById(R.id.lbl_item_text);

            container = itemView.findViewById(R.id.cont_item_root);
            container.setOnClickListener(this);
            Picasso.with(context ).load("http://i.imgur.com/DvpvklR.png").into(thumbnail);
        }

        @Override
        public void onClick(View v) {
            Log.d("janitha", "item clicked");

        }

我也阅读了以下内容：-Picasso and context

期待有人的帮助。

Answer 1

您还没有从构造函数中保存上下文。这样做：

public class WishListAdapter extends 
     RecyclerView.Adapter<WishListAdapter.DerpHolder> {

    private List<WishListItem> listData;
    private LayoutInflater inflater;
    Context context;

    public WishListAdapter(List<WishListItem> listData, Context c) {
        inflater = LayoutInflater.from(c);
        this.listData = listData;
        this.context = c;
    }

    @Override
    public WishListAdapter.DerpHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.wish_list_item, parent, false);
        return new DerpHolder(view);
    }

    @Override
    public void onBindViewHolder(DerpHolder holder, int position) {

    }

    public void setListData(ArrayList<WishListItem> exerciseList) {
        this.listData.clear();
        this.listData.addAll(exerciseList);
    }

    @Override
    public int getItemCount() {
        return listData.size();
    }

    class DerpHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        ImageView thumbnail;
        TextView title;
        TextView subTitle;
        View container;


        public DerpHolder(View itemView) {
            super(itemView);
            thumbnail = itemView.findViewById(R.id.im_item_icon);

            //subTitle = itemView.findViewById(R.id.lbl_item_sub_title);

            //title = itemView.findViewById(R.id.lbl_item_text);

            container = itemView.findViewById(R.id.cont_item_root);
            container.setOnClickListener(this);
            Picasso.with(context ).load("http://i.imgur.com/DvpvklR.png").into(thumbnail);
        }

        @Override
        public void onClick(View v) {
            Log.d("janitha", "item clicked");

        }

Answer 2

试试，

private Context context;

在你的构造函数中，

this.context = c;

现在您可以使用 'context' 作为参数。

Answer 3

修改您的代码如下：

private List<WishListItem> listData;
private LayoutInflater inflater;
private Context mContext;

public WishListAdapter(List<WishListItem> listData, Context c) {
    inflater = LayoutInflater.from(c);
    this.listData = listData;
    this.mContext = c;
}

然后将 mContext 与 Picasso 一起使用：

Picasso.with(mContext).load("http://i.imgur.com/DvpvklR.png").into(thumbnail);

Answer 4

请像下面这样声明上下文变量并使用它：

public class WishListAdapter extends RecyclerView.Adapter<WishListAdapter.DerpHolder> {

    private List<WishListItem> listData;
    private LayoutInflater inflater;
    private Context context

    public WishListAdapter(List<WishListItem> listData, Context c) {
        inflater = LayoutInflater.from(c);
        this.listData = listData;
        this.context = c;
    }

    @Override
    public WishListAdapter.DerpHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.wish_list_item, parent, false);
        return new DerpHolder(view);
    }

    @Override
    public void onBindViewHolder(DerpHolder holder, int position) {

    }

    public void setListData(ArrayList<WishListItem> exerciseList) {
        this.listData.clear();
        this.listData.addAll(exerciseList);
    }

    @Override
    public int getItemCount() {
        return listData.size();
    }

    class DerpHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        ImageView thumbnail;
        TextView title;
        TextView subTitle;
        View container;


        public DerpHolder(View itemView) {
            super(itemView);
            thumbnail = itemView.findViewById(R.id.im_item_icon);

            //subTitle = itemView.findViewById(R.id.lbl_item_sub_title);

            //title = itemView.findViewById(R.id.lbl_item_text);

            container = itemView.findViewById(R.id.cont_item_root);
            container.setOnClickListener(this);
            Picasso.with(context ).load("http://i.imgur.com/DvpvklR.png").into(thumbnail);
        }

        @Override
        public void onClick(View v) {
            Log.d("janitha", "item clicked");

        }

毕加索 - 找不到 "context"

Picasso - can't find "context"

java

android

android-recyclerview

picasso

android-context