리사이클 러 뷰 어댑터에서 컨텍스트를 얻는 방법

리사이클 러 뷰 어댑터에서 컨텍스트를 얻는 방법

---

picasso 라이브러리를 사용하여 imageView에 URL을로드하려고하지만 contextpicasso 라이브러리를 올바르게 사용할 수 없습니다 .

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();
    }

}

---

여기 몇 가지 옵션이 있습니다.

1. 패스 ContextFeedAdapter에 인수로 및 클래스 필드로 유지
2. Context필요할 때 주입하려면 의존성 주입을 사용하십시오 . 나는 그것에 대해 읽는 것이 좋습니다. 이를위한 훌륭한 도구가 있습니다 -Dagger by Square

3. 모든 View물건 에서 가져옵니다 . 귀하의 경우 이것이 효과가 있습니다.

   holder.pub_image.getContext()

   으로는 pub_image입니다 ImageView.

---

전역 변수를 추가 할 수 있습니다.

private Context context;

그런 다음 여기에서 컨텍스트를 지정하십시오.

@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);
    // set the Context here 
    context = parent.getContext();
    return vh;
}

해피 코딩 :)

---

pub_image 컨텍스트 ( holder.pub_image.getContext())를 사용할 수 있습니다 .

@Override
public void onBindViewHolder(ViewHolder ViewHolder, int position) {

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

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


}

---

짧은 답변:

Context context;

@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
    super.onAttachedToRecyclerView(recyclerView);
    context = recyclerView.getContext();
}

다른 답변이 좋지 않은 이유를 설명하십시오.

1. Passing Context to the adapter is completely unnecessary, since RecyclerView you can access it from inside the class
2. Obtaining Context at ViewHolder level means that you do it every time you bind or create a ViewHolder. You duplicate operations.
3. I don't think you need to worry about any memory leak. If your adapter lingers outside your Activity lifespan (which would be weird) then you already have a leak.

---

First globally declare

Context mContext;

pass context with the constructor, by modifying it.

public FeedAdapter(List<Post> myDataset, Context context) {
    mDataset = myDataset;
    this.mContext = context;
}

then use the mContext whereever you need it

---

You can use like this view.getContext()

Example

holder.tv_room_name.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Toast.makeText(v.getContext(), "", Toast.LENGTH_SHORT).show();


        }
    });

---

Create a constructor of FeedAdapter :

Context context; //global
public FeedAdapter(Context context)
{
   this.context = context;  
}

and in Activity

FeedAdapter obj = new FeedAdapter(this);

---

First add a global variable

Context mContext;

Then change your constructor to this

public FeedAdapter(Context context, List<Post> myDataset) {
    mContext = context;
    mDataset = myDataset;
}

The pass your context when creating the adapter.

FeedAdapter myAdapter = new FeedAdapter(this,myDataset);

---

you can use this:

itemView.getContext()

---

You can define:

Context ctx; 

And on onCreate initialise ctx to:

ctx=parent.getContext(); 

Note: Parent is a ViewGroup.

참고URL : https://stackoverflow.com/questions/32136973/how-to-get-a-context-in-a-recycler-view-adapter