RecyclerView 的使用

这里只是简单记录一下怎么使用

第一步:Layout文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/RecyclerViewId"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</LinearLayout>

 第2步:Activity
这里是实现的瀑布视图

public class RecyclerViewActivity extends Activity {
    private RecyclerView mRecyclerView;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.recycler_view_demo);
        mRecyclerView = findViewById(R.id.RecyclerViewId);

        List<String> dataList = new ArrayList<>();
        for(int i=0;i<30;i++){
            dataList.add(new String("数据" + (i+1)));
        }
        RecycleViewAdapter recycleAdapter = new RecycleViewAdapter(this,dataList);
//截图2的效果
         /*GridLayoutManager manager = new GridLayoutManager(this,4);
        manager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup(){

            @Override
            public int getSpanSize(int position) {
                if(position == 4) return  3;
                if(position == 8) return  2;
                return 1;
            }
        });*/
//截图1的效果
        StaggeredGridLayoutManager manager=new StaggeredGridLayoutManager(4, OrientationHelper.VERTICAL);
        mRecyclerView.setLayoutManager(manager);
        mRecyclerView.setAdapter(recycleAdapter);
    }
}

第3步:实现Adapter

public class RecycleViewAdapter extends RecyclerView.Adapter<RecycleViewAdapter.MyViewHolder>{
    private View mItemView;
    private Context mContext;
    private List<String> mList;

    public RecycleViewAdapter(Context context, List<String> list) {
        this.mContext = context;
        mList = list;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        mItemView = LayoutInflater.from(mContext).inflate(R.layout.item_text,parent,false);
        MyViewHolder holder = new MyViewHolder(mItemView);
        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        if(position == 4){
            ViewGroup.LayoutParams params = holder.rootView.getLayoutParams();
            params.height = 150 * 3 *2;//holder.rootView.getMeasuredHeight() *2;
            holder.rootView.setLayoutParams(params);
        }
        holder.textView.setText(mList.get(position));
    }

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

    class MyViewHolder extends RecyclerView.ViewHolder{
        TextView textView;
        ViewGroup rootView ;
        public MyViewHolder(View itemView) {
            super(itemView);
            rootView= (ViewGroup)itemView;
            textView = (TextView) itemView.findViewById(R.id.textView);
        }
    }
}

其他:导入support 包