Android RecyclerView擴充卡簡單使用及問題

1.添加依賴

implementation ‘androidx.recyclerview:recyclerview:1.2.0-alpha01’

2.建立一個擴充卡

public class RecyclerBaseAdapter extends RecyclerView.Adapter<RecyclerBaseAdapter.InnerHolder> {
    List<String> mData;


    public RecyclerBaseAdapter(List<String> listData) {
        this.mData=listData;
    }



    @NonNull
    @Override
    public InnerHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        //View view = View.inflate(parent.getContext(), R.layout.recyclerview_item, null);//出現的問題向後看
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_item,parent,false);
        return new InnerHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull InnerHolder holder, int position) {
        holder.tvItem.setText(mData.get(position));
    }

    @Override
    public int getItemCount() {
        if (mData != null) {
            return mData.size();
        }
        return 0;
    }

    public class InnerHolder extends RecyclerView.ViewHolder {
        @BindView(R.id.tv_item)
        TextView tvItem;
        public InnerHolder(@NonNull View itemView) {
            super(itemView);
            ButterKnife.bind(this,itemView);
        }
    }
}
           

3.在Activity中使用

RecyclerBaseAdapter mBaseAdapter = new RecyclerBaseAdapter(mlist);
    //實作ListView 的效果
    LinearLayoutManager layoutManager = new LinearLayoutManager(this);
    layoutManager.setReverseLayout(true);
    layoutManager.setOrientation(RecyclerView.VERTICAL);
    recyclerview.setLayoutManager(layoutManager);
   //實作GridView 的效果
     /*GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 2);
    gridLayoutManager.setOrientation(RecyclerView.HORIZONTAL);*/

    //實作瀑布流
   /* StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(2,RecyclerView.VERTICAL );
    layoutManager.setReverseLayout(true);*/

    recyclerview.setLayoutManager(layoutManager);
    recyclerview.setAdapter(mBaseAdapter);
           

4.出現的問題

a.圖檔就能說明問題了

關于LayoutInflater的講解相關連結LayoutInflater

b.和RecyclerView沒關系，但是是做這個例子出現的問題，項目中用了Butterknife

依賴需要注意下

implementation ‘com.jakewharton:butterknife:10.2.1’

annotationProcessor ‘com.jakewharton:butterknife-compiler:10.2.1’

不然會空指針異常