RecyclerView上拉加载封装代码

public abstract class baserecypradapter<t> extends recyclerview.adapter<baserecypradapter.baseviewholder> {
  private static final string tag = "baserecypradapter";

  public static final int view_item = 0;
  public static final int view_prog = 1;

  public list<t> mdatalist;

  private final context mcontext;
  private final recyclerview mrecyclerview;
  private int totalitemcount;
  private int lastvisibleitemposition;
  boolean isshowfootview = false;
  private handler handler = new handler();

  private static final int state_normal = 0;
  private static final int state_loading = 1;
  private static final int state_load_complete = 2;
  private int mstate = state_normal;

  public baserecypradapter(context context, recyclerview recyclerview) {
    mcontext = context;
    mrecyclerview = recyclerview;
    if (mrecyclerview.getlayoutmanager() instanceof linearlayoutmanager) {
      final linearlayoutmanager linearlayoutmanager = (linearlayoutmanager) recyclerview.getlayoutmanager();

      mrecyclerview.addonscrolllistener(new recyclerview.onscrolllistener() {
        @override
        public void onscrollstatechanged(recyclerview recyclerview, int newstate) {
          super.onscrollstatechanged(recyclerview, newstate);
          int extent = recyclerview.computeverticalscrollextent();
          int range = recyclerview.computeverticalscrollrange();
          log.e(tag, "\n extent = " + extent + "\n range = " + range);

          if (range > extent) {
            if(!isshowfootview){
              notifydatasetchanged();
            }
            isshowfootview = true;
          } else {
            isshowfootview = false;
          }

          totalitemcount = linearlayoutmanager.getitemcount();
          if (mstate == state_normal && newstate == recyclerview.scroll_state_idle &&
              totalitemcount == lastvisibleitemposition + 1 && range > extent) {
            mstate = state_loading;
            handler.post(new runnable() {
              @override
              public void run() {
                if (mloadmoredatalistener != null) {
                  mloadmoredatalistener.loadmoredata();
                }
              }
            });
          }
        }

        @override
        public void onscrolled(recyclerview recyclerview, int dx, int dy) {
          super.onscrolled(recyclerview, dx, dy);
          lastvisibleitemposition = linearlayoutmanager.findlastvisibleitemposition();
        }
      });
    }

  }


  @override
  public baseviewholder oncreateviewholder(viewgroup parent, int viewtype) {
    baseviewholder holder = null;
    view view = null;
    if (viewtype == view_prog) {
      view = layoutinflater.from(parent.getcontext()).inflate(r.layout.item_footer, parent, false);
    } else {
      view = layoutinflater.from(parent.getcontext()).inflate(getlayoutid(viewtype), parent, false);
    }
    holder = new baseviewholder(view);
    return holder;
  }


  @override
  public void onbindviewholder(baseviewholder holder, int position) {
    if (holder.getitemviewtype() == baserecypradapter.view_prog) {
//      logtool.loge_debug(tag, "onbindviewholder--->" + mstate);
      progressbar progressbar = (progressbar) holder.getview(r.id.progressbar);
      textview text = (textview) holder.getview(r.id.text);

      if (mstate == state_load_complete) {
        progressbar.setvisibility(view.gone);
        text.settext(mcontext.getstring(r.string.没有数据了));
      } else {
        progressbar.setvisibility(view.visible);
        text.settext(mcontext.getstring(r.string.正在加载中));
      }
    }

    if (holder.getitemviewtype() == baserecypradapter.view_item) {
      onbinddata(holder, position);
    }
  }

  @override
  public int getitemcount() {
    if (isshowfootview) {
      return mdatalist == null ? 0 : mdatalist.size() + 1;
    } else {
      return mdatalist == null ? 0 : mdatalist.size();
    }
  }


  //根据不同的数据返回不同的viewtype
  @override
  public int getitemviewtype(int position) {
    if (mdatalist == null)
      return view_item;

    if (position == mdatalist.size()) {
      return view_prog;
    } else {
      return view_item;
    }
  }

  /**
   * 根据type 返回不同的布局
   *
   * @param type
   * @return
   */
  public abstract int getlayoutid(int type);

  public abstract void onbinddata(baseviewholder holder, int position);


  public static class baseviewholder extends recyclerview.viewholder {
    private map<integer, view> mviewmap;
    public view view;

    public baseviewholder(view itemview) {
      super(itemview);

      view = itemview;
      mviewmap = new hashmap<>();
    }

    /**
     * 获取设置的view
     *
     * @param id
     * @return
     */
    public view getview(int id) {
      view view = mviewmap.get(id);
      if (view == null) {
        view = itemview.findviewbyid(id);
        mviewmap.put(id, view);
      }
      return view;
    }
  }

  public void stoploadmore() {
    mstate = state_normal;
    notifydatasetchanged();
  }

  public void loadcomplete() {
    mstate = state_load_complete;
    notifyitemchanged(getitemcount()-1);
  }

  public void setdata(list<t> datas) {
    mdatalist = datas;
  }

  private loadmoredatalistener mloadmoredatalistener;

  public void setloadmoredatalistener(loadmoredatalistener mloadmoredatalistener) {
    this.mloadmoredatalistener = mloadmoredatalistener;
  }

  public interface loadmoredatalistener {
    void loadmoredata();
  }
}

public class mainactivity extends appcompatactivity {

  private static final string tag = "recyactivity";
  private recyclerview mrecyclerview;
  private list<string> list = new arraylist<>();
  private myrecyviewadapter madapter;
  private handler handler = new handler();

  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);

    init();
  }

  private void init() {
    initview();
    initdata();

    initlistener();
  }

  private void initview() {
    mrecyclerview = (recyclerview) findviewbyid(r.id.recyclerview);

    //创建一个linearlayoutmanager对象
    linearlayoutmanager linearlayoutmanager = new linearlayoutmanager(
        this, linearlayoutmanager.vertical, false);
    mrecyclerview.setlayoutmanager(linearlayoutmanager);

    //创建adapter对象
    madapter = new myrecyviewadapter(this, mrecyclerview);
    mrecyclerview.setadapter(madapter);
    madapter.setdata(list);//设置数据
  }

  //初始化数据
  private void initdata() {
    for (int i = 0; i < 15; i++) {
      list.add("data---------->" + i);
    }
  }


  //初始化监听
  private void initlistener() {
    //加载更多回调监听
    madapter.setloadmoredatalistener(new baserecypradapter.loadmoredatalistener() {
      @override
      public void loadmoredata() {
        //加入null值此时adapter会判断item的type
        log.e(tag, "loadmoredata--->");
        handler.postdelayed(new runnable() {
          @override
          public void run() {
            if (list.size() < 30) {
              for (int i = 0; i < 5; i++) {
                list.add("load more data---------->" + i);
              }
              madapter.stoploadmore();
            } else {
              madapter.loadcomplete();
            }
          }
        }, 500);
      }
    });
  }

  class myrecyviewadapter extends baserecypradapter<string> {

    public myrecyviewadapter(context context, recyclerview recyclerview) {
      super(context, recyclerview);
    }

    @override
    public int getlayoutid(int type) {
      return r.layout.item_view;
    }

    @override
    public void onbinddata(baseviewholder holder, int position) {
      log.e(tag, "onbinddata--->" + position);
      if (mdatalist == null || mdatalist.isempty())
        return;

      textview tv = (textview) holder.getview(r.id.tv_name);
      if (tv != null) {
        tv.settext("data--------->" + position);
      }
    }
  }
}