如何在回收器视图适配器中获取上下文 [英] How to get a context in a recycler view adapter

问题描述

我正在尝试使用picasso库来加载url到imageView，但是我无法获得 context 来正确使用picasso库。

I'm trying to use picasso library to be able to load url to imageView, but I'm not able to get the context to use the picasso library correctly.

public class FeedAdapter extends RecyclerView.Adapter<FeedAdapter.ViewHolder> {
    private List<Post> mDataset;



    // Provide a reference to the views for each data item
    // Complex data items may need more than one view per item, and
    // you provide access to all the views for a data item in a view holder
    public class ViewHolder extends RecyclerView.ViewHolder {
        // each data item is just a string in this case
        public TextView txtHeader;
        public ImageView pub_image;
        public ViewHolder(View v) {
            super(v);
            txtHeader = (TextView) v.findViewById(R.id.firstline);
            pub_image = (ImageView) v.findViewById(R.id.imageView);


        }
    }




    // Provide a suitable constructor (depends on the kind of dataset)
    public FeedAdapter(List<Post> myDataset) {
        mDataset = myDataset;
    }

    // Create new views (invoked by the layout manager)
    @Override
    public FeedAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
                                                   int viewType) {
        // create a new view
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.feedholder, parent, false);
        // set the view's size, margins, paddings and layout parameters
        ViewHolder vh = new ViewHolder(v);
        return vh;
    }

    // Replace the contents of a view (invoked by the layout manager)
    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        // - get element from your dataset at this position
        // - replace the contents of the view with that element

        holder.txtHeader.setText(mDataset.get(position).getPost_text());

        Picasso.with(this.context).load("http://i.imgur.com/DvpvklR.png").into(holder.pub_image);


    }

    // Return the size of your dataset (invoked by the layout manager)
    @Override
    public int getItemCount() {
        return mDataset.size();
    }

}

推荐答案

这里有几个选项：

1. 传递上下文作为参数到FeedAdapter并将其保留为类字段


2. 在需要时使用依赖注入来注入 Context 。我强烈建议阅读它。有一个很好的工具 - 广场 Dagger



3. 获取它来自任何查看对象。在你的情况下，这可能适合你：

1. Pass Context as an argument to FeedAdapter and keep it as class field
2. Use dependency injection to inject Context when you need it. I strongly suggest reading about it. There is a great tool for that -- Dagger by Square

3. Get it from any View object. In your case this might work for you:

holder.pub_image.getContext（）

As pub_image 是 ImageView 。

这篇关于如何在回收器视图适配器中获取上下文的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！