是用來替代ListView和Gallery的

可以實現列表和九宮格的橫向和縱向的滑動以及瀑布流效果

要想使用就要添加v7包的支持

需要聯合使用Adapter和ViewHolder和LayoutManager

縱向和橫向滑動效果的實現

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

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"></android.support.v7.widget.RecyclerView>

</LinearLayout>

public class MainActivity extends AppCompatActivity {
    /**
     * rv相關聯的類:
     * 1.布局管理器,用來設置rv的顯示風格,如列表,網格,瀑布流,XXXLayoutManager
     * 2.適配器,Adapter
     * 3.ViewHolder
     */

    @BindView(R.id.rv)
    RecyclerView mRv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);

        //1.設置布局管理器
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);//這個就是實現橫向滑動
        mRv.setLayoutManager(linearLayoutManager);

        //2.設置適配器
        mRv.setAdapter(new MyRvAdapter());
    }

    private class MyRvAdapter extends RecyclerView.Adapter {
        //創建ViewHolder
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.item, parent, false);
            return new MyRvViewHolder(view);
        }

        //對ViewHolder里面的控件進行賦值
        @Override
        public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
            MyRvViewHolder myRvViewHolder = (MyRvViewHolder) holder;
            myRvViewHolder.setData(position);
        }

        //RV的條目數量
        @Override
        public int getItemCount() {
            return 50;
        }
    }

    private class MyRvViewHolder extends RecyclerView.ViewHolder {

        private TextView mTextView;
        private int position;

        public MyRvViewHolder(View itemView) {
            super(itemView);
            mTextView = itemView.findViewById(R.id.tv_test);
        }

        public void setData(int position) {
            this.position = position;
            mTextView.setText("哈哈哈哈哈" + position);
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:layout_margin="5dp"
              android:background="#f00"
              android:orientation="vertical">
    <!--條目的布局-->
    <TextView
        android:id="@+id/tv_test"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:gravity="center"
        android:text="hello"/>

</LinearLayout>