java - 尝试在 .Adapter.ListSourceAdap 的空对象引用上调用虚拟方法 Model.WebSite.getSources()'

问题描述

我不知道我在哪里定义了一个空对象，请帮我找出来！看起来我试图使用来自网站的空对象并将其传递给 ListSourceAdapter 但我不知道为什么以及如何修复它，请帮帮我。

 java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.List com.example.nutshell.myapplication.Model.WebSite.getSources()' on a null object reference
    at com.example.nutshell.myapplication.Adapter.ListSourceAdapter.getItemCount(ListSourceAdapter.java:106)

ListSourceAdapter （我通过 getSource() 的地方）

     class ListSourceViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
{
    ItemClickListener itemClickListener;
    TextView source_title;
    CircleImageView source_image;

    public ListSourceViewHolder(View itemView) {
        super(itemView);

    source_image=(CircleImageView) itemView.findViewById(R.id.source_image);
    source_title=(TextView)itemView.findViewById(R.id.source_name);

    }
public void setItemClickListener(ItemClickListener itemClickListener)
{
    this.itemClickListener=itemClickListener;
}
    @Override
    public void onClick(View v) {
        itemClickListener.onClick(v, getAdapterPosition(),false);
    }
}


public class ListSourceAdapter extends  RecyclerView.Adapter<ListSourceViewHolder> {

private Context context;
private WebSite webSite;
private IconBetterIdeaService mService;

    public ListSourceAdapter(Context context, WebSite webSite) {
        this.context = context;
        this.webSite = webSite;

    mService=Common.getIconService();

    }

    @NonNull
    @Override
    public ListSourceViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater=LayoutInflater.from(parent.getContext());
        View itemView=inflater.inflate(R.layout.source_layout,parent,false);
        return new ListSourceViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull final ListSourceViewHolder holder, int position) {
    StringBuilder iconBetterAPI=new StringBuilder(" https://icons.better-idea.org/allicons.json?url=");
    iconBetterAPI.append(webSite.getSources().get(position).getUrl());
    mService.getIconUrl(iconBetterAPI.toString()).enqueue(new Callback<IconBetterIdea>() {
        @Override
        public void onResponse(Call<IconBetterIdea> call, Response<IconBetterIdea> response) {
            if (response.body().getIcons().size() > 0)
            {
                Picasso.with(context)
                        .load(response.body().getIcons().get(0).getUrl()).into(holder.source_image);

            }
        }

        @Override
        public void onFailure(Call<IconBetterIdea> call, Throwable t) {

        }
    });
    holder.source_title.setText(webSite.getSources().get(position).getName());
    holder.setItemClickListener(new ItemClickListener() {
        @Override
        public void onClick(View view, int position, boolean isLongClick) {

            Intent intent=new Intent(context, ListNews.class);
            intent.putExtra("source",webSite.getSources().get(position).getId());
        }
    });
    }

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

和 WebSite.java 是：

public class WebSite {

    private String status;
    private List<Source> sources;

    public WebSite() {
    }

    public WebSite(String status, List<Source> sources) {
        this.status = status;
        this.sources = sources;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public List<Source> getSources() {
        return sources;
    }

    public void setSources(List<Source> sources) {
        this.sources = sources;
    }
}

标签： javaandroid-studio

java - 尝试在 .Adapter.ListSourceAdap 的空对象引用上调用虚拟方法 Model.WebSite.getSources()'

问题描述

解决方案

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