RecyclerView适配器中的投掷错误，创建视图持有人时

Question

我正在尝试在片段内使用RecyclerView。但是，一旦我完成代码，适配器中的contex就会显示错误。

在功能onCreateViewHolder()中，context显示错误：

from (android.content.Context) in layoutInflator cannot be applied to (com.practice.musicplayer.libraryfragment)

public class SongCardAdapter extends  RecyclerView.Adapter<SongCardAdapter.viewHolder> {

private ArrayList<SongCardModel> list;
private LibraryFragment context;

public SongCardAdapter(ArrayList<SongCardModel> list, LibraryFragment context) {
    this.list = list;
    this.context = context;
}

@NonNull
@Override
public viewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(context).inflate(R.layout.libray_recycler_view_layout, parent, false);
    return new viewHolder(view);
}

@Override
public void onBindViewHolder(@NonNull viewHolder holder, int position) {
    SongCardModel model = list.get(position);
    holder.albumArt.setImageResource(model.getImage());
    holder.songName.setText(model.getSongName());
}

@Override
public int getItemCount() {
    //setting the size of the recyclerView to the size of the list
    return list.size();
}

public class viewHolder extends RecyclerView.ViewHolder {
    ImageView albumArt;
    TextView songName;
    public viewHolder(@NonNull View itemView) {
        super(itemView);
        albumArt = itemView.findViewById(R.id.album_art);
        songName = itemView.findViewById(R.id.song_name);
    }
}
}

对于崩溃日志

java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View androidx.recyclerview.widget.RecyclerView.findViewById(int)' on a null object reference
        at com.practice.musicplayer.LibraryFragment.onCreateView(LibraryFragment.java:27)

第27行，我有此代码：

libraryRecyclerView = (RecyclerView)libraryRecyclerView.findViewById(R.id.library_recyclerview);

Answer 1

您可以替换代码中的行吗？>

this.context = context;
with

this.context = context.getContext();
并查看是否有效。

Answer 2

不要在适配器内部传递LibraryFragment，而是传递Context，然后在适配器初始化片段中传递活动。更改您的适配器构造函数：

Answer 3

您必须致电parent.getContext()