Android RecyclerView上拉加载和下拉刷新（基础版）

这里讲述的是用谷歌原生的swiperefreshlayout，进行刷新，以及利用recycleview的滚动事件，判断是否到最后一个item，进行加载更多，这里加载更多是在recycleview的适配器中使用不同item进行完成的。

这是activity的xml布局：

<?xml version="1.0" encoding="utf-8"?>
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical">

 <android.support.v4.widget.swiperefreshlayout
  android:id="@+id/swipe_refresh_layout"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  >

  <android.support.v7.widget.recyclerview
   android:id="@+id/recyclerview"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:background="#f0f0f0"
   android:cliptopadding="false"
   android:paddingbottom="16dp"
   android:paddingtop="16dp"/>

 </android.support.v4.widget.swiperefreshlayout>

 <com.rey.material.widget.progressview
  android:id="@+id/progress_loading_main"
  app:pv_autostart="true"
  app:pv_circular="true"   app:pv_progressstyle="@style/material.drawable.circularprogress"
  app:pv_progressmode="indeterminate"
  android:layout_width="50dp"
  android:layout_height="50dp"
  android:visibility="gone"
  android:layout_centerinparent="true"/>
</relativelayout>

接下来是对应activity中的代码：

import android.os.bundle;
import android.os.handler;
import android.support.annotation.nullable;
import android.support.design.widget.snackbar;
import android.support.v4.app.fragment;
import android.support.v4.widget.swiperefreshlayout;
import android.support.v7.widget.linearlayoutmanager;
import android.support.v7.widget.recyclerview;
import android.view.layoutinflater;
import android.view.view;
import android.view.viewgroup;

import com.retrofit.wangfei.viewpagertablayout.util.constance;
import com.retrofit.wangfei.viewpagertablayout.r;
import com.retrofit.wangfei.viewpagertablayout.adapter.myrecycleviewadapter;
import com.rey.material.widget.progressview;

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

import butterknife.bind;
import butterknife.butterknife;


public class homefragment extends fragment {

 @bind(r.id.recyclerview)
 recyclerview recyclerview;
 @bind(r.id.swipe_refresh_layout)
 swiperefreshlayout swiperefreshlayout;
 @bind(r.id.progress_loading_main)
 progressview progress_loading_main; // 加载数据时显示的进度圆圈
 private linearlayoutmanager mrecycleviewlayoutmanager;

 private int mpagenum = 1;

 private list<string> lists = new arraylist<>();
 private myrecycleviewadapter madapter;

 public static homefragment newinstance() {
  homefragment fragment = new homefragment();
  return fragment;
 }

 @override
 public void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);

 }

 @override
 public view oncreateview(layoutinflater inflater, viewgroup container,
        bundle savedinstancestate) {
  view view = inflater.inflate(r.layout.fragment_home, container, false);
  butterknife.bind(this, view);
  return view;
 }

 /**在oncreateview方法后执行*/
 @override
 public void onviewcreated(view view, @nullable bundle savedinstancestate) {
  super.onviewcreated(view, savedinstancestate);
  madapter = new myrecycleviewadapter(lists,getactivity());
  initrecyclerview();
  swiperefreshlayout.setcolorschemeresources(constance.colors);//设置下拉刷新控件变换的四个颜色
  recyclerview.setadapter(madapter);
  recyclerviewonitemclicklistener();
  refresh();
  loadmore(madapter);
  progress_loading_main.setvisibility(view.visible);
  initdata();
 }

 @override
 public void ondestroyview() {
  super.ondestroyview();
  butterknife.unbind(this);
 }

 /**进入页面的初始化数据*/
 private void initdata(){
  new handler().postdelayed(new runnable() {

   @override
   public void run() {
    netnewslist(true);
    progress_loading_main.setvisibility(view.gone);
   }
  }, 2000);
 }

 /**recyclerview每个item的点击事件*/
 private void recyclerviewonitemclicklistener() {
  madapter.setonitemclicklistener(new myrecycleviewadapter.onitemclicklistener() {
   @override
   public void onitemclick(view view, int position) {
    snackbar.make(view, "fly", snackbar.length_short).show();
   }
  });
 }

 /**
  * 初始化recyclerview
  */
 private void initrecyclerview() {
//  recyclerview.setitemanimator(new defaultitemanimator());
//  recyclerview.sethasfixedsize(true);
  mrecycleviewlayoutmanager = new linearlayoutmanager(getactivity());
  recyclerview.setlayoutmanager(mrecycleviewlayoutmanager); // 设置recycleview，显示是listview还是gridview还是瀑布流

 }

 /**下拉刷新*/
 private void refresh() {
  swiperefreshlayout.setonrefreshlistener(new swiperefreshlayout.onrefreshlistener() {
   @override
   public void onrefresh() {
    new handler().postdelayed(new runnable() {

     @override
     public void run() {
      netnewslist(true);
      swiperefreshlayout.setrefreshing(false); // 停止刷新
     }
    }, 2000);
   }
  });
 }

 /**
  * 设置上拉加载更多
  *
  * @param adapter recyclerview适配器
  */
 public void loadmore(final myrecycleviewadapter adapter) {
  recyclerview.addonscrolllistener(new recyclerview.onscrolllistener() {

   private int lastvisibleitem;

   @override
   public void onscrolled(recyclerview recyclerview, int dx, int dy) {
    super.onscrolled(recyclerview, dx, dy);
    lastvisibleitem = mrecycleviewlayoutmanager.findlastvisibleitemposition(); // 滑动到最后一个
   }

   @override
   public void onscrollstatechanged(recyclerview recyclerview, int newstate) {
    super.onscrollstatechanged(recyclerview, newstate);

    // 效果在暂停时显示, 否则会导致重绘异常
    if (newstate == recyclerview.scroll_state_idle
      && lastvisibleitem + 1 == adapter.getitemcount()) {

     if (lists != null && lists.size() >= 10) { // 真实开发中要设置mnews.size()大于加载分页显示的个数
      adapter.loadlayout.setvisibility(view.visible);
      //加载更多
      new handler().postdelayed(new runnable() {

       @override
       public void run() {
        netnewslist(false);
       }
      }, 2000);
     }
    }
   }
  });
 }

 /**
  * 从网络加载数据列表
  *
  * @param isrefresh 是否刷新 true 为刷新，false为不刷新
  */
 private void netnewslist(boolean isrefresh) {
//  viewdelegate.showloading();
  if (isrefresh) {
   mpagenum = 1;
  } else {
   mpagenum++;
  }

  if (isrefresh) {
   if (!lists.isempty()) {
    lists.clear();
   }
  }
  // todo 这里把页数mpagenum上传到服务端
  lists.clear();
  lists.addall(getdata());
  madapter.notifydatasetchanged();
 }

 private list<string> list = new arraylist<>();
 private list<string> getdata() {
  for (int i = 0; i < 10; i++) {
   list.add(i + "");
  }
  return list;
 }
}

接下来是recycleview适配器中的xml文件：

这是正常item的布局，至于用cardview是为了让item展示出来的效果更好看

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.cardview xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical" android:layout_width="match_parent"
 android:layout_height="wrap_content">

 <textview
  android:id="@+id/text"
  android:layout_width="match_parent"
  android:layout_height="50dp"
  android:text=""
  android:gravity="center"/>

</android.support.v7.widget.cardview>

这是现实上拉加载的布局文件，作为不同item共同展示在recycleview上面：

<?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:id="@+id/load_layout"
 android:visibility="gone"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:gravity="center"
 android:orientation="horizontal"
 android:paddingbottom="12dip"
 android:paddingtop="12dip">

 <com.rey.material.widget.progressview
  app:pv_autostart="true"
  app:pv_circular="true"
  app:pv_progressstyle="@style/material.drawable.circularprogress"
  app:pv_progressmode="indeterminate"
  android:layout_width="24dp"
  android:layout_height="24dp" />

 <textview
  android:id="@+id/more_data_msg"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:textsize="16sp"
  android:layout_marginleft="10dp"
  android:text="正在加载..." />
</linearlayout>

下面我们看看recycleview适配器的写法：

import android.app.activity;
import android.support.v7.widget.recyclerview;
import android.view.layoutinflater;
import android.view.view;
import android.view.viewgroup;
import android.widget.linearlayout;
import android.widget.textview;

import com.retrofit.wangfei.viewpagertablayout.r;

import java.util.list;

import butterknife.bind;
import butterknife.butterknife;

/**
 * created by android studio
 * description: recycleview的适配器
 */
public class myrecycleviewadapter extends recyclerview.adapter {

 private final static int type_item = 0x01;
 private final static int type_footer = 0x02;

 private list<string> lists;
 private activity context;

 public linearlayout loadlayout;

 private onitemclicklistener monitemclicklistener; // 声明接口

 public myrecycleviewadapter(list<string> lists, activity context) {
  this.lists = lists;
  this.context = context;
 }

 @override
 public recyclerview.viewholder oncreateviewholder(viewgroup parent, int viewtype) {
  if (type_item == viewtype) {
   view view = layoutinflater.from(parent.getcontext()).inflate(r.layout.recycle_view_item, parent,false);
   itemviewholder itemviewholder = new itemviewholder(view);
   return itemviewholder;
  } else {
   view view = layoutinflater.from(parent.getcontext()).inflate(r.layout.list_footer, parent,false);
   loadlayout = (linearlayout) view.findviewbyid(r.id.load_layout);
   return new footviewholder(view);
  }
 }

 @override
 public void onbindviewholder(recyclerview.viewholder holder, int position) {
  if (holder instanceof itemviewholder) {
   string text = lists.get(position);
   itemviewholder itemholder = (itemviewholder) holder;
   itemholder.text.settext(text);
  }
 }

 @override
 public int getitemcount() {
  return lists.size() + 1;
 }

 @override
 public int getitemviewtype(int position) {
  if (position + 1 == getitemcount()) {
   return type_footer;
  } else {
   return type_item;
  }
 }

 public class itemviewholder extends recyclerview.viewholder implements view.onclicklistener {

  @bind(r.id.text)
  textview text;

  public itemviewholder(view itemview) {
   super(itemview);
   butterknife.bind(this,itemview);
   itemview.setonclicklistener(this);
  }

  @override
  public void onclick(view v) {
   monitemclicklistener.onitemclick(v,getposition());
  }
 }

 public class footviewholder extends recyclerview.viewholder {
  public footviewholder(view itemview) {
   super(itemview);
  }
 }

 /**调到外部使用*/
 public void setonitemclicklistener(onitemclicklistener onitemclicklistener){
  this.monitemclicklistener = onitemclicklistener;
 }

 /**定义接口*/
 public interface onitemclicklistener{
  void onitemclick(view v,int position);
 }
}

最后是刷新控件的4个不同颜色：

public interface constance {
 /**
  * 下拉刷新控件变化的四个颜色
  */
 int[] colors = new int[] {
   android.r.color.holo_green_light, android.r.color.holo_blue_light,
   android.r.color.holo_green_light, android.r.color.holo_blue_light
 };
}

所需要的依赖库：

compile 'com.android.support:appcompat-v7:23.3.0'
 compile 'com.android.support:design:23.3.0'
 compile 'com.jakewharton:butterknife:7.0.1'
 compile 'com.android.support:support-v4:23.3.0'
 /**谷歌服务*/
 compile 'com.google.android.gms:play-services:8.4.0'
 compile 'com.github.rey5137:material:1.2.2'

到这里就结束了，完成了下拉刷新和上拉加载更多的实现。

下面说说recyclerview的使用最基础的三点：

一：

recyclerview.sethasfixedsize(true); 
//方法用来使recyclerview保持固定的大小，该信息被用于自身的优化。

二：

recyclerview.setitemanimator(new defaultitemanimator());
itemanimator会根据适配器上收到的通知动画显示视图组的修改。基本上，它会自动显示添加和移除条目动画。这也不是一个简单的类，但我们发现defaultitemanimator已经可以运行得很好了。

三：

recyclerview.setlayoutmanager(mrecycleviewlayoutmanager); 

// 设置recycleview，显示是listview还是gridview还是瀑布流。

// 显示是listview 
linearlayoutmanager mrecycleviewlayoutmanager = new linearlayoutmanager(context);

// 显示是gridview,参数一：上下文，参数二：列数 
gridlayoutmanager mgridlayoutmanager=new gridlayoutmanager(context, 4);

// 显示是瀑布流，参数一：显示几列，参数二：现实的方向，垂直或水平 
staggeredgridlayoutmanager mstaggeredgridlayoutmanager=new staggeredgridlayoutmanager(2, staggeredgridlayoutmanager.vertical);

更多详细请参考：android recyclerview艺术般的控件使用完全解析

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。