返回值显示使用if时变量可能尚未初始化

Question

我正在使用回收站视图并创建一个受欢迎的视频列表。.我有2个观看者1用于照片，另一个用于视频，我使用此代码来区分照片和视频...但是当我使用 if

Answer 1

这是因为在if条件为假的情况下，您没有提供任何视图类型

MERGE (a), (b), (c), (a)-[r1]->(b)<-[r3]-(d)

在(a)-[r1]->(b)<-[r2]-(c) ^ | [r3] | (d) 中用默认值初始化 if(moviesList.get(position).getPopularlist().contains("true")) 。

getItemViewType

完整代码为

int viewType

Answer 2

只需在模型类中添加另一个字段：

class Photo{
    public static final int VIDEO_TYPE=1;
    public static final int IMAGE_TYPE=2;
    // your fileds
    public int type;// ( update this field at the time of building your list
                      //apply your logic for differentciate VIDEO_TYPE & IMAGE_TYPE )
    }

将类型更新为VIDEO_TYPE或IMAGE_TYPE；

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

        ArrayList<Photo> moviesList=new ArrayList<>();

        public Trending_adapter(List<Photo> moviesList) {
            this.moviesList = moviesList;
        }

        @NonNull
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            //findViewById...
            mContext = parent.getContext();
            switch (viewType) {
                case Photo.VIDEO_TYPE:
                    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.video_type, parent, false);
                    mContext = parent.getContext();
                    return new VideoHolder(v);
                case Photo.IMAGE_TYPE:
                    View i = LayoutInflater.from(parent.getContext()).inflate(R.layout.main_list, parent, false);
                    mContext = parent.getContext();
                    return new PhotoHolder(i);
            }
            return null;
        }

    @Override
    public int getItemViewType ( int position ) {
    return moviesList.get(position).type;
       }

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

@Override
public void onBindViewHolder(@NonNull final RecyclerView.ViewHolder holder, final int position) {

Photo model=moviesList.get(position);
    switch ( model.type ) {
        case IMAGE_TYPE:
            //do your stuff here for IMAGE_TYPE type
            break;
        case VIDEO_TYPE:
          //do your stuff here for VIDEO_TYPE type
            break;

    }


}


        class VideoHolder extends RecyclerView.ViewHolder {
            static final int LAYOUT_RES = R.layout.main_list;
            private ExoPlayerViewHelper helper;
            private CircleImageView profile_image;
            //private String likeString;
            public VideoHolder(View view) {
                super(view);
            }     
        }


        class PhotoHolder extends RecyclerView.ViewHolder {
              public PhotoHolder(View view){
                super(view);

            }
        }

        }

It works fine for you.