android - 将 RecyclerView 显示到片段中

Question

我有方法：

private void initImageBitmaps() {
        mImageUrls.add("imageUrl");
        mNames.add("abcd");
        initRecyclerView();
    }

    private void initRecyclerView() {
        Log.d(TAG, "initRecyclerView: init recyclerview.");
        RecyclerView recyclerView = findViewById(R.id.recyclerv_view);
        RecyclerViewAdapter adapter = new RecyclerViewAdapter(this, mNames, mImageUrls);
        recyclerView.setAdapter(adapter);
        //recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setLayoutManager(new GridLayoutManager(this, 2));
    }

将图像添加到我的回收站视图中。如果它在活动中，我会initImageBitmaps()在 OnCreate 内部调用。不幸的是，我必须在片段中使用它，问题是：如何将这些方法实现到扩展片段的类？当然，所有内容都将显示在 RecyclerView 中，并在 xml 中带有 recycler_view id。

编辑：我的适配器：

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder>{

    private static final String TAG = "RecyclerViewAdapter";

    private ArrayList<String> mImageNames = new ArrayList<>();
    private ArrayList<String> mImages = new ArrayList<>();
    private Context mContext;

    public RecyclerViewAdapter(WallpapersFragment context, ArrayList<String> imageNames, ArrayList<String> images ) {
        mImageNames = imageNames;
        mImages = images;
        mContext = context;
        //Rquired is android.content.context and found is WallpapersFragment from my project
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_listitem, parent, false);
        ViewHolder holder = new ViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        Log.d(TAG, "onBindViewHolder: called.");

        Glide.with(mContext)
                .asBitmap()
                .load(mImages.get(position))
                .into(holder.image);

        holder.imageName.setText(mImageNames.get(position));

        holder.parentLayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(mContext, GalleryActivity.class);
                intent.putExtra("image_url", mImages.get(position));
                intent.putExtra("image_name", mImageNames.get(position));
                mContext.startActivity(intent);
            }
        });
    }

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


    public class ViewHolder extends RecyclerView.ViewHolder{

        ImageView image;
        TextView imageName;
        RelativeLayout parentLayout;

        public ViewHolder(View itemView) {
            super(itemView);
            image = itemView.findViewById(R.id.image);
            imageName = itemView.findViewById(R.id.image_name);
            parentLayout = itemView.findViewById(R.id.parent_layout);
        }
    }
}

只有当我mContext = context;在适配器中评论时它才会编译。然后错误是： java.lang.NullPointerException: You cannot start a load on a not yet attached View or a Fragment where getActivity() return null （通常在附加 Fragment 之前或 Fragment 之后调用 getActivity() 时发生被破坏）。

标签： androidandroid-recyclerview

Answer 1

initRecyclerView(view);

接着：

 recyclerView = view.findViewById(R.id.recyclerv_view);