package com.example.osserver.recycler;

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.*;
import android.support.v7.widget.LinearLayoutManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends ActionBarActivity {

  private RecyclerView mRecyclerView;
  private List<String> mDatas;
  private HomeAdapter mAdapter;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initData();
    mRecyclerView = (RecyclerView)findViewById(R.id.id_recyclerview);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    mRecyclerView.setAdapter(mAdapter = new HomeAdapter());
    mRecyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.HORIZONTAL_LIST));

  }

  private void initData() {
        mDatas = new ArrayList<String>();
        for (int i ='A';i<='Z';i++){
          mDatas.add(""+(char)i);
    }
  }
class HomeAdapter extends RecyclerView.Adapter<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();
  }
}

  class MyViewHolder extends RecyclerView.ViewHolder
  {
    TextView tv;
    public MyViewHolder(View view) {
      super(view);
      tv = (TextView)view.findViewById(R.id.id_num);
    }
  }

}

package com.zhy.sample.demo_recyclerview;

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * limitations under the License.
 */

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.support.v7.widget.RecyclerView.State;
import android.util.Log;
import android.view.View;


/**
 * This class is from the v7 samples of the Android SDK. It's not by me!
 * <p/>
 * See the license above for details.
 */
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);
    }

  }


  public 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);
    }
  }

  public 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);
    }
  }

  @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);
    }
  }
}