Android RecyclerView添加上拉加载更多效果

先看一下效果

刷新的时候是这样的:

没有更多的时候是这样的:

既然有刷新的时候有两种状态就要定义两个状态

//普通布局的type
static final int type_item = 0;
//脚布局
static final int type_footer = 1;

在特定的时候去显示:

 @override
  public int getitemviewtype(int position) {
    //如果position加1正好等于所有item的总和,说明是最后一个item,将它设置为脚布局
    if (position + 1 == getitemcount()) {
      return type_footer;
    } else {
      return type_item;
    }
  }

然后根据这个type来inflate不同的布局:

 @override
  public recyclerview.viewholder oncreateviewholder(viewgroup parent, int viewtype) {
    if (viewtype == type_item) {
      view view = view.inflate(mcontext, r.layout.item_recycler, null);
      myviewholder holder = new myviewholder(view);
      return holder;
    } else if (viewtype == type_footer) {
      //脚布局
      view view = view.inflate(mcontext, r.layout.recycler_load_more_layout, null);
      footviewholder footviewholder = new footviewholder(view);
      return footviewholder;
    }
    return null;
  }

以上只是控制了loading布局的出现可隐藏,还要2中状态需要控制就是上面的2个图,一个是正在加载,一个是加载完成状态,这两个状态在adapter里显然是控制不了的,必须要在请求数据的时候才能知道这两种状态,而加载数据又是在activity中执行的,所以我们需要一个用来传递状态的方法:

/**
   * 改变脚布局的状态的方法,在activity根据请求数据的状态来改变这个状态
   *
   * @param state
   */
  public void changestate(int state) {
    this.footer_state = state;
    notifydatasetchanged();
  }

用来接收状态的变量:

//上拉加载更多
// static final int pull_load_more = 0;
  //正在加载更多
  static final int loading_more = 1;
  //没有更多
  static final int no_more = 2;
  //脚布局当前的状态,默认为没有更多
  int footer_state = 1;

然后就可以根据这几种状态来控制布局控件的改变了:

 @override
  public void onbindviewholder(recyclerview.viewholder holder, int position) {
    if (holder instanceof myviewholder) {
      ((myviewholder) holder).mtextview.settext(mlist.get(position));
    } else if (holder instanceof footviewholder) {
      footviewholder footviewholder = (footviewholder) holder;
      if (position == 0) {//如果第一个就是脚布局,,那就让他隐藏
        footviewholder.mprogressbar.setvisibility(view.gone);
        footviewholder.tv_line1.setvisibility(view.gone);
        footviewholder.tv_line2.setvisibility(view.gone);
        footviewholder.tv_state.settext("");
      }
      switch (footer_state) {//根据状态来让脚布局发生改变
//        case pull_load_more://上拉加载
//          footviewholder.mprogressbar.setvisibility(view.gone);
//          footviewholder.tv_state.settext("上拉加载更多");
//          break;
        case loading_more:
          footviewholder.mprogressbar.setvisibility(view.visible);
          footviewholder.tv_line1.setvisibility(view.gone);
          footviewholder.tv_line2.setvisibility(view.gone);
          footviewholder.tv_state.settext("正在加载...");
          break;
        case no_more:
          footviewholder.mprogressbar.setvisibility(view.gone);
          footviewholder.tv_line1.setvisibility(view.visible);
          footviewholder.tv_line2.setvisibility(view.visible);
          footviewholder.tv_state.settext("我是有底线的");
          footviewholder.tv_state.settextcolor(color.parsecolor("#ff00ff"));
          break;
      }
    }
  }

不要忘了返回的count也要加1,因为添加了一个脚布局:

 @override
  public int getitemcount() {
    return mlist != null ? mlist.size() + 1 : 0;
  }

那么什么时候去传递状态到adapter呢?这里就需要给recyclerview添加滑动监听了,当他滑动到底部的时候显示加载中的状态:

//给recyclerview添加滑动监听
    mrecycler.addonscrolllistener(new recyclerview.onscrolllistener() {
      @override
      public void onscrollstatechanged(recyclerview recyclerview, int newstate) {
        super.onscrollstatechanged(recyclerview, newstate);
        /*
        到达底部了,如果不加!isloading的话到达底部如果还一滑动的话就会一直进入这个方法
        就一直去做请求网络的操作,这样的用户体验肯定不好.添加一个判断,每次滑倒底只进行一次网络请求去请求数据
        当请求完成后,在把isloading赋值为false,下次滑倒底又能进入这个方法了
         */
        if (newstate == recyclerview.scroll_state_idle && lastvisibleitem + 1 == madapter.getitemcount() && !isloading) {
          //到达底部之后如果footview的状态不是正在加载的状态,就将 他切换成正在加载的状态
          if (page < totlepage) {
            log.e("duanlian", "onscrollstatechanged: " + "进来了");
            isloading = true;
            madapter.changestate(1);
            new handler().postdelayed(new runnable() {
              @override
              public void run() {
                getdata();
                page++;
              }
            }, 2000);
          } else {
            madapter.changestate(2);

          }
        }
      }

      @override
      public void onscrolled(recyclerview recyclerview, int dx, int dy) {
        super.onscrolled(recyclerview, dx, dy);
        //拿到最后一个出现的item的位置
        lastvisibleitem = linearlayoutmanager.findlastvisibleitemposition();
      }
    });

重点就这几个,下面给出脚布局:

<?xml version="1.0" encoding="utf-8"?>
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/ll_below"
        android:layout_width="match_parent"
        android:layout_height="45dp"
  >

  <linearlayout
    android:layout_width="fill_parent"
    android:layout_height="45dp"
    android:gravity="center"
    android:orientation="horizontal">

    <textview
      android:id="@+id/tv_line1"
      android:layout_width="60dp"
      android:layout_height="1dp"
      android:layout_marginright="10dp"
      android:background="#ff00ff"
      android:visibility="gone"/>

    <progressbar
      android:id="@+id/progressbar"
      android:layout_width="25dp"
      android:layout_height="25dp"
      android:visibility="visible"/>

    <textview
      android:id="@+id/foot_view_item_tv"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_marginleft="4dp"
      android:text="上拉加载更多"/>

    <textview
      android:id="@+id/tv_line2"
      android:layout_width="60dp"
      android:layout_height="1dp"
      android:layout_marginleft="10dp"
      android:background="#ff00ff"
      android:visibility="gone"/>
  </linearlayout>
</relativelayout>

adapter的代码:

package com.duanlian.recyclerviewloadmoredemo;

import android.content.context;
import android.graphics.color;
import android.support.v7.widget.recyclerview;
import android.view.view;
import android.view.viewgroup;
import android.widget.progressbar;
import android.widget.textview;

import java.util.list;


public class myrecycleradapter extends recyclerview.adapter<recyclerview.viewholder> {
  private context mcontext;
  private list<string> mlist;
  //普通布局的type
  static final int type_item = 0;
  //脚布局
  static final int type_footer = 1;
  //  //上拉加载更多
//  static final int pull_load_more = 0;
  //正在加载更多
  static final int loading_more = 1;
  //没有更多
  static final int no_more = 2;
  //脚布局当前的状态,默认为没有更多
  int footer_state = 1;

  public myrecycleradapter(context context, list<string> list) {
    mcontext = context;
    mlist = list;
  }

  @override
  public recyclerview.viewholder oncreateviewholder(viewgroup parent, int viewtype) {
    if (viewtype == type_item) {
      view view = view.inflate(mcontext, r.layout.item_recycler, null);
      myviewholder holder = new myviewholder(view);
      return holder;
    } else if (viewtype == type_footer) {
      //脚布局
      view view = view.inflate(mcontext, r.layout.recycler_load_more_layout, null);
      footviewholder footviewholder = new footviewholder(view);
      return footviewholder;
    }
    return null;
  }

  @override
  public void onbindviewholder(recyclerview.viewholder holder, int position) {
    if (holder instanceof myviewholder) {
      ((myviewholder) holder).mtextview.settext(mlist.get(position));
    } else if (holder instanceof footviewholder) {
      footviewholder footviewholder = (footviewholder) holder;
      if (position == 0) {//如果第一个就是脚布局,,那就让他隐藏
        footviewholder.mprogressbar.setvisibility(view.gone);
        footviewholder.tv_line1.setvisibility(view.gone);
        footviewholder.tv_line2.setvisibility(view.gone);
        footviewholder.tv_state.settext("");
      }
      switch (footer_state) {//根据状态来让脚布局发生改变
//        case pull_load_more://上拉加载
//          footviewholder.mprogressbar.setvisibility(view.gone);
//          footviewholder.tv_state.settext("上拉加载更多");
//          break;
        case loading_more:
          footviewholder.mprogressbar.setvisibility(view.visible);
          footviewholder.tv_line1.setvisibility(view.gone);
          footviewholder.tv_line2.setvisibility(view.gone);
          footviewholder.tv_state.settext("正在加载...");
          break;
        case no_more:
          footviewholder.mprogressbar.setvisibility(view.gone);
          footviewholder.tv_line1.setvisibility(view.visible);
          footviewholder.tv_line2.setvisibility(view.visible);
          footviewholder.tv_state.settext("我是有底线的");
          footviewholder.tv_state.settextcolor(color.parsecolor("#ff00ff"));
          break;
      }
    }
  }


  @override
  public int getitemviewtype(int position) {
    //如果position加1正好等于所有item的总和,说明是最后一个item,将它设置为脚布局
    if (position + 1 == getitemcount()) {
      return type_footer;
    } else {
      return type_item;
    }
  }

  @override
  public int getitemcount() {
    return mlist != null ? mlist.size() + 1 : 0;
  }

  /**
   * 正常布局的viewholder
   */
  class myviewholder extends recyclerview.viewholder {
    textview mtextview;

    public myviewholder(view itemview) {
      super(itemview);
      mtextview = (textview) itemview.findviewbyid(r.id.item_textview);
    }
  }

  /**
   * 脚布局的viewholder
   */
  public static class footviewholder extends recyclerview.viewholder {
    private progressbar mprogressbar;
    private textview tv_state;
    private textview tv_line1;
    private textview tv_line2;


    public footviewholder(view itemview) {
      super(itemview);
      mprogressbar = (progressbar) itemview.findviewbyid(r.id.progressbar);
      tv_state = (textview) itemview.findviewbyid(r.id.foot_view_item_tv);
      tv_line1 = (textview) itemview.findviewbyid(r.id.tv_line1);
      tv_line2 = (textview) itemview.findviewbyid(r.id.tv_line2);

    }
  }

  /**
   * 改变脚布局的状态的方法,在activity根据请求数据的状态来改变这个状态
   *
   * @param state
   */
  public void changestate(int state) {
    this.footer_state = state;
    notifydatasetchanged();
  }

}

activity中的代码:

package com.duanlian.recyclerviewloadmoredemo;

import android.os.bundle;
import android.os.handler;
import android.support.v7.app.appcompatactivity;
import android.support.v7.widget.linearlayoutmanager;
import android.support.v7.widget.recyclerview;
import android.util.log;

import java.util.arraylist;
import java.util.list;

public class mainactivity extends appcompatactivity {

  private recyclerview mrecycler;
  private list<string> mlist;
  private list<string> list;
  private myrecycleradapter madapter;
  linearlayoutmanager linearlayoutmanager;
  int lastvisibleitem;
  int page = 0;
  boolean isloading = false;//用来控制进入getdata()的次数
  int totlepage = 5;//模拟请求的一共的页数

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

  private void initview() {
    mrecycler = (recyclerview) findviewbyid(r.id.recycler);
    linearlayoutmanager = new linearlayoutmanager(this);
    mrecycler.setlayoutmanager(linearlayoutmanager);
    mlist = new arraylist<>();
    madapter = new myrecycleradapter(this, mlist);
    mrecycler.setadapter(madapter);
    //给recyclerview添加滑动监听
    mrecycler.addonscrolllistener(new recyclerview.onscrolllistener() {
      @override
      public void onscrollstatechanged(recyclerview recyclerview, int newstate) {
        super.onscrollstatechanged(recyclerview, newstate);
        /*
        到达底部了,如果不加!isloading的话到达底部如果还一滑动的话就会一直进入这个方法
        就一直去做请求网络的操作,这样的用户体验肯定不好.添加一个判断,每次滑倒底只进行一次网络请求去请求数据
        当请求完成后,在把isloading赋值为false,下次滑倒底又能进入这个方法了
         */
        if (newstate == recyclerview.scroll_state_idle && lastvisibleitem + 1 == madapter.getitemcount() && !isloading) {
          //到达底部之后如果footview的状态不是正在加载的状态,就将 他切换成正在加载的状态
          if (page < totlepage) {
            log.e("duanlian", "onscrollstatechanged: " + "进来了");
            isloading = true;
            madapter.changestate(1);
            new handler().postdelayed(new runnable() {
              @override
              public void run() {
                getdata();
                page++;
              }
            }, 2000);
          } else {
            madapter.changestate(2);

          }
        }
      }

      @override
      public void onscrolled(recyclerview recyclerview, int dx, int dy) {
        super.onscrolled(recyclerview, dx, dy);
        //拿到最后一个出现的item的位置
        lastvisibleitem = linearlayoutmanager.findlastvisibleitemposition();
      }
    });

  }

  /**
   * 模拟请求数据
   */
  private void getdata() {
    list = new arraylist<>();
    for (int i = 0; i < 10; i++) {
      list.add("第" + i + "条");
    }
    mlist.addall(list);
    isloading = false;
    madapter = new myrecycleradapter(this, mlist);
    mrecycler.setadapter(madapter);
  }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。