RecyclerView

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;

/**
 * Created by lenovo on 2017/10/13.
 */

public class DividerItemDecoration extends RecyclerView.ItemDecoration{
    private static final int[] ATTRS = new int[]{
            android.R.attr.listDivider
    };

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

    private Drawable mDivider;

    private int mOrientation;
    public DividerItemDecoration(Context context, int orientation) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
      a.recycle();
      setOrientation(orientation);
   }

    public void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }
    @Override
    public void onDraw(Canvas c, RecyclerView parent) {
        Log.v("recyclerview - itemdecoration", "onDraw()");

        if (mOrientation == VERTICAL_LIST) {
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);
        }

    }


    private void drawHorizontal(Canvas c, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getHeight() - parent.getPaddingBottom();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int left = child.getRight() + params.rightMargin;
            final int right = left + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    private void drawVertical(Canvas c, RecyclerView parent) {
        final int left = parent.getPaddingLeft();
        final int right = parent.getWidth() - parent.getPaddingRight();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            android.support.v7.widget.RecyclerView v = new android.support.v7.widget.RecyclerView(parent.getContext());
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }
    @Override
    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        }
    }

}

MainActivity

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private RecyclerView recycler;
    private ArrayList<Object> list;
    private ArrayList<String> mDatas;
    private HomeAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initData();
         recycler= (RecyclerView) findViewById(R.id.recycler);
        findViewById(R.id.btlist).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //线性式
                recycler.setLayoutManager(new LinearLayoutManager(MainActivity.this));
            }
        });

        recycler.setAdapter(mAdapter = new HomeAdapter());
        //线性分割线
        recycler.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
        recycler.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.HORIZONTAL_LIST));
        findViewById(R.id.btgrid).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //网格式
                recycler.setLayoutManager(new GridLayoutManager(MainActivity.this,3));
            }
        });
                //瀑布流
                recycler.setLayoutManager(new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL));

       //添加动画
        recycler.setItemAnimator(new DefaultItemAnimator());
      findViewById(R.id.btjia).setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
              mAdapter.addData(1);
          }
      });
        findViewById(R.id.btjian).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mAdapter.removeData(1);
            }
        });
    }
    protected void initData()
    {
        mDatas = new ArrayList<String>();
        for (int i =0; i <20; i++)
        {
            mDatas.add("" + i);
        }
    }


    class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder>
    {

        @Override
        public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
        {
            MyViewHolder holder = new MyViewHolder(LayoutInflater.from(
                    MainActivity.this).inflate(R.layout.item, parent,
                    false));
            return holder;
        }

        @Override
        public void onBindViewHolder(MyViewHolder holder, int position)
        {
            holder.tv.setText(mDatas.get(position));
        }

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

        public void addData(int i) {
            mDatas.add(i, "Insert One");
            mAdapter.notifyItemInserted(i);
        }

        public void removeData(int i) {
            mDatas.remove(i);
            mAdapter.notifyItemRemoved(i);
        }

        class MyViewHolder extends RecyclerView.ViewHolder
        {

            TextView tv;

            public MyViewHolder(View view)
            {
                super(view);
                tv = (TextView) view.findViewById(R.id.tv);
            }
        }
    }


}


依赖
compile 'com.android.support:recyclerview-v7:21.0.+'

<?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"

    android:orientation="vertical" xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.bwie.wangshaoliang20171013.MainActivity">
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    >
    <Button
    android:id="@+id/btjia"
    android:textSize="20dp"
    android:text="+"
        android:layout_weight="1"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
    <Button
        android:id="@+id/btjian"
        android:textSize="20dp"
        android:text="-"
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
    <Button
        android:id="@+id/btlist"
        android:text="list"
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
    <Button
        android:id="@+id/btgrid"
        android:text="grid"
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
    <Button
        android:id="@+id/btflow"
        android:text="flow"
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>
    <android.support.v7.widget.RecyclerView
    android:divider="#ffff0000"
    android:dividerHeight="10dp"
        android:layout_weight="1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/recycler"
    ></android.support.v7.widget.RecyclerView>

</LinearLayout>

 
原文地址:https://www.cnblogs.com/shangliang88/p/7660678.html