Android开源项目PullToRefresh下拉刷新功能详解

先看看效果图：

开源项地址：https://github.com/chrisbanes/android-pulltorefresh 

下拉刷新这个功能我们都比较常见了，今天介绍的就是这个功能的实现。我将按照这个开源库的范例来一点一点介绍，今天是介绍比较常见的pulltorefreshlistview，是让listview有下拉刷新功能。 

1.下载项目包，将library包导入即可，其他的包暂时不用

2.分析源码，看我们可以设置的有哪些 

<?xml version="1.0" encoding="utf-8"?>
<resources>

 <declare-styleable name="pulltorefresh">

 <!-- a drawable to use as the background of the refreshable view -->
 <!-- 设置刷新view的背景 -->
 <attr name="ptrrefreshableviewbackground" format="reference|color" />

 <!-- a drawable to use as the background of the header and footer loading views -->
 <!-- 设置头部view的背景 -->
 <attr name="ptrheaderbackground" format="reference|color" />

 <!-- text color of the header and footer loading views -->
 <!-- 设置头部/底部文字的颜色 -->
 <attr name="ptrheadertextcolor" format="reference|color" />

 <!-- text color of the header and footer loading views sub header -->
 <!-- 设置头部/底部副标题的文字颜色 -->
 <attr name="ptrheadersubtextcolor" format="reference|color" />

 <!-- mode of pull-to-refresh that should be used -->
 <!-- 设置下拉刷新的模式，有多重方式可选。无刷新功能，从顶部刷新，从底部刷新，二者都有，只允许手动刷新 -->
 <attr name="ptrmode">
  <flag name="disabled" value="0x0" />
  <flag name="pullfromstart" value="0x1" />
  <flag name="pullfromend" value="0x2" />
  <flag name="both" value="0x3" />
  <flag name="manualonly" value="0x4" />

  <!-- these last two are depreacted -->
  <!-- 这两个属性不推荐了，用上面的代替即可 -->
  <flag name="pulldownfromtop" value="0x1" />
  <flag name="pullupfrombottom" value="0x2" />
 </attr>

 <!-- whether the indicator overlay(s) should be used -->
 <!-- 是否显示指示箭头 -->
 <attr name="ptrshowindicator" format="reference|boolean" />

 <!-- drawable to use as loading indicator. changes both header and footer. -->
 <!-- 指示箭头的图片 -->
 <attr name="ptrdrawable" format="reference" />

 <!-- drawable to use as loading indicator in the header view. overrides value set in ptrdrawable. -->
 <!-- 顶部指示箭头的图片，设置后会覆盖ptrdrawable中顶部的设置 -->
 <attr name="ptrdrawablestart" format="reference" />

 <!-- drawable to use as loading indicator in the fooer view. overrides value set in ptrdrawable. -->
 <!-- 底部指示箭头的图片，设置后会覆盖ptrdrawable中底部的设置 -->
 <attr name="ptrdrawableend" format="reference" />

 <!-- whether android's built-in over scroll should be utilised for pull-to-refresh. -->
 <attr name="ptroverscroll" format="reference|boolean" />

 <!-- base text color, typeface, size, and style for header and footer loading views -->
 <!-- 设置文字的基本字体 -->
 <attr name="ptrheadertextappearance" format="reference" />

 <!-- base text color, typeface, size, and style for header and footer loading views sub header -->
 <!-- 设置副标题的基本字体 -->
 <attr name="ptrsubheadertextappearance" format="reference" />

 <!-- style of animation should be used displayed when pulling. -->
 <!-- 设置下拉时标识图的动画，默认为rotate -->
 <attr name="ptranimationstyle">
  <flag name="rotate" value="0x0" />
  <flag name="flip" value="0x1" />
 </attr>

 <!-- whether the user can scroll while the view is refreshing -->
 <!-- 设置刷新时是否允许滚动，一般为true -->
 <attr name="ptrscrollingwhilerefreshingenabled" format="reference|boolean" />

 <!--
  whether pulltorefreshlistview has it's extras enabled. this allows the user to be 
  able to scroll while refreshing, and behaves better. it acheives this by adding
  header and/or footer views to the listview.
 -->
 <!-- 允许在listview中添加头/尾视图 -->
 <attr name="ptrlistviewextrasenabled" format="reference|boolean" />

 <!--
  whether the drawable should be continually rotated as you pull. this only
  takes effect when using the 'rotate' animation style.
 -->
 <!-- 当设置rotate时，可以用这个来设置刷新时旋转的图片 -->
 <attr name="ptrrotatedrawablewhilepulling" format="reference|boolean" />

 <!-- below here are depreceated. do not use. -->
 <attr name="ptradapterviewbackground" format="reference|color" />
 <attr name="ptrdrawabletop" format="reference" />
 <attr name="ptrdrawablebottom" format="reference" />
 </declare-styleable>

</resources>

看到有这么多可以设置的属性，别以为真的就可以定制了。真正要定制还得到layout中改变刷新布局 

3.开始用它建立自己的工程
 设置布局文件
 就是插入pulltorefreshlistview

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context="${relativepackage}.${activityclass}" 
 android:background="#000000">

<!-- the pulltorefreshlistview replaces a standard listview widget. -->

 <com.handmark.pulltorefresh.library.pulltorefreshlistview
 xmlns:ptr="http://schemas.android.com/apk/res-auto"
 android:id="@+id/pull_refresh_list"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:cachecolorhint="#000000"
 android:divider="#19000000"
 android:dividerheight="4dp"
 android:fadingedge="none"
 android:fastscrollenabled="false"
 android:footerdividersenabled="false"
 android:headerdividersenabled="false"
 android:smoothscrollbar="true" 
 ptr:ptranimationstyle="rotate"
 ptr:ptrheadertextcolor="#ffffff"
 ptr:ptrheadersubtextcolor="#00ffff"
 ptr:ptrheaderbackground="@null"
 ptr:ptrdrawable="@drawable/ic_launcher"/>
 
</relativelayout>

开始编写代码 

1.找到这个控件，并且设置监听器 

这里面用到了一个日期的工具类，其实就是设置上次下拉的时间的。此外在下拉后会触发一个异步任务 

 /**
 * 设置下拉刷新的listview的动作
 */
 private void initptrlistview() {
 mpullrefreshlistview = (pulltorefreshlistview) findviewbyid(r.id.pull_refresh_list);
 //设置拉动监听器
 mpullrefreshlistview.setonrefreshlistener(new onrefreshlistener<listview>() {

  @override
  public void onrefresh(pulltorefreshbase<listview> refreshview) {
  //设置下拉时显示的日期和时间
  string label = dateutils.formatdatetime(getapplicationcontext(), system.currenttimemillis(),
   dateutils.format_show_time | dateutils.format_show_date | dateutils.format_abbrev_all);

  // 更新显示的label
  refreshview.getloadinglayoutproxy().setlastupdatedlabel(label);
  // 开始执行异步任务，传入适配器来进行数据改变
  new getdatatask(mpullrefreshlistview, madapter,mlistitems).execute();
  }
 });

 // 添加滑动到底部的监听器
 mpullrefreshlistview.setonlastitemvisiblelistener(new onlastitemvisiblelistener() {
  
  @override
  public void onlastitemvisible() {
  toast.maketext(getapplication(), "已经到底了", toast.length_short).show();
  }
 });
 
 //mpullrefreshlistview.isscrollingwhilerefreshingenabled();//看刷新时是否允许滑动
 //在刷新时允许继续滑动
 mpullrefreshlistview.setscrollingwhilerefreshingenabled(true);
 //mpullrefreshlistview.getmode();//得到模式
 //上下都可以刷新的模式。这里有两个选择：mode.pull_from_start，mode.both，pull_from_end
 mpullrefreshlistview.setmode(mode.both);
 
 /**
  * 设置反馈音效
  */
 soundpulleventlistener<listview> soundlistener = new soundpulleventlistener<listview>(this);
 soundlistener.addsoundevent(state.pull_to_refresh, r.raw.pull_event);
 soundlistener.addsoundevent(state.reset, r.raw.reset_sound);
 soundlistener.addsoundevent(state.refreshing, r.raw.refreshing_sound);
 mpullrefreshlistview.setonpulleventlistener(soundlistener);
 }

2.从上面的那个控件中，得到它包含的listview，并且设置适配器 

 //普通的listview对象
 private listview actuallistview;
 //添加一个链表数组，来存放string数组，这样就可以动态增加string数组中的内容了
 private linkedlist<string> mlistitems;
 //给listview添加一个普通的适配器
 private arrayadapter<string> madapter;

这里用到了一个linkedlist的对象，这个是一个类似于arraylist的链表数组，比较方便在开头和末尾添加string 

 /**
 * 设置listview的适配器
 */
 private void initlistview() {
 //通过getrefreshableview()来得到一个listview对象
 actuallistview = mpullrefreshlistview.getrefreshableview();
 
 string []data = new string[] {"android","ios","wp","java","c++","c#"};
 mlistitems = new linkedlist<string>();
 //把string数组中的string添加到链表中
 mlistitems.addall(arrays.aslist(data));
 
 madapter = new arrayadapter<>(getapplicationcontext(), 
  android.r.layout.simple_list_item_1, mlistitems);
 actuallistview.setadapter(madapter);
 }

 

3.写一个异步任务，来模仿从网络加载数据

这里要注意的是，加载完后要出发刷新完成和通知适配器改变的方法

package com.kale.ptrlistviewtest;

import java.util.linkedlist;

import android.os.asynctask;
import android.widget.arrayadapter;

import com.handmark.pulltorefresh.library.pulltorefreshlistview;
import com.handmark.pulltorefresh.library.pulltorefreshbase.mode;

/**
 * @author:jack tony
 * @tips :通过异步任务来加载网络中的数据，进行更新
 * @date :2014-10-14
 */
public class getdatatask extends asynctask<void, void, void>{

 private pulltorefreshlistview mpullrefreshlistview;
 private arrayadapter<string> madapter;
 private linkedlist<string> mlistitems;
 
 public getdatatask(pulltorefreshlistview listview,
  arrayadapter<string> adapter,linkedlist<string> listitems) {
 // todo 自动生成的构造函数存根
 mpullrefreshlistview = listview;
 madapter = adapter;
 mlistitems = listitems;
 }
 
 @override
 protected void doinbackground(void... params) {
 //模拟请求
 try {
  thread.sleep(2000);
 } catch (interruptedexception e) {
 }
 return null;
 }
 
 @override
 protected void onpostexecute(void result) {
 // todo 自动生成的方法存根
 super.onpostexecute(result);
 //得到当前的模式
 mode mode = mpullrefreshlistview.getcurrentmode();
 if(mode == mode.pull_from_start) {
  mlistitems.addfirst("这是刷新出来的数据");
 }
 else {
  mlistitems.addlast("这是刷新出来的数据");
 }
 // 通知数据改变了
 madapter.notifydatasetchanged();
 // 加载完成后停止刷新
 mpullrefreshlistview.onrefreshcomplete();
 
 }
 


}

贴上acitivty中的全部代码 

mainactivity.java 

package com.kale.ptrlistviewtest;

import java.util.arrays;
import java.util.linkedlist;

import android.app.activity;
import android.os.bundle;
import android.text.format.dateutils;
import android.widget.arrayadapter;
import android.widget.listview;
import android.widget.toast;

import com.handmark.pulltorefresh.library.pulltorefreshbase;
import com.handmark.pulltorefresh.library.pulltorefreshbase.mode;
import com.handmark.pulltorefresh.library.pulltorefreshbase.onlastitemvisiblelistener;
import com.handmark.pulltorefresh.library.pulltorefreshbase.onrefreshlistener;
import com.handmark.pulltorefresh.library.pulltorefreshbase.state;
import com.handmark.pulltorefresh.library.pulltorefreshlistview;
import com.handmark.pulltorefresh.library.extras.soundpulleventlistener;

public class mainactivity extends activity {
 
 //一个可以下拉刷新的listview对象
 private pulltorefreshlistview mpullrefreshlistview;
 //普通的listview对象
 private listview actuallistview;
 //添加一个链表数组，来存放string数组，这样就可以动态增加string数组中的内容了
 private linkedlist<string> mlistitems;
 //给listview添加一个普通的适配器
 private arrayadapter<string> madapter;
 
 @override
 protected void oncreate(bundle savedinstancestate) {
 super.oncreate(savedinstancestate);
 setcontentview(r.layout.activity_main);
 
 initview();

 //一打开应用就自动刷新，下面语句可以写到刷新按钮里面
 mpullrefreshlistview.setrefreshing(true);
 //new getdatatask(mpullrefreshlistview, madapter, mlistitems).execute();
 //mpullrefreshlistview.setrefreshing(false);

 }

 private void initview() {
 initptrlistview();
 initlistview();
 }
 
 /**
 * 设置下拉刷新的listview的动作
 */
 private void initptrlistview() {
 mpullrefreshlistview = (pulltorefreshlistview) findviewbyid(r.id.pull_refresh_list);
 //设置拉动监听器
 mpullrefreshlistview.setonrefreshlistener(new onrefreshlistener<listview>() {

  @override
  public void onrefresh(pulltorefreshbase<listview> refreshview) {
  //设置下拉时显示的日期和时间
  string label = dateutils.formatdatetime(getapplicationcontext(), system.currenttimemillis(),
   dateutils.format_show_time | dateutils.format_show_date | dateutils.format_abbrev_all);

  // 更新显示的label
  refreshview.getloadinglayoutproxy().setlastupdatedlabel(label);
  // 开始执行异步任务，传入适配器来进行数据改变
  new getdatatask(mpullrefreshlistview, madapter,mlistitems).execute();
  }
 });

 // 添加滑动到底部的监听器
 mpullrefreshlistview.setonlastitemvisiblelistener(new onlastitemvisiblelistener() {
  
  @override
  public void onlastitemvisible() {
  toast.maketext(getapplication(), "已经到底了", toast.length_short).show();
  }
 });
 
 //mpullrefreshlistview.isscrollingwhilerefreshingenabled();//看刷新时是否允许滑动
 //在刷新时允许继续滑动
 mpullrefreshlistview.setscrollingwhilerefreshingenabled(true);
 //mpullrefreshlistview.getmode();//得到模式
 //上下都可以刷新的模式。这里有两个选择：mode.pull_from_start，mode.both，pull_from_end
 mpullrefreshlistview.setmode(mode.both);
 
 /**
  * 设置反馈音效
  */
 soundpulleventlistener<listview> soundlistener = new soundpulleventlistener<listview>(this);
 soundlistener.addsoundevent(state.pull_to_refresh, r.raw.pull_event);
 soundlistener.addsoundevent(state.reset, r.raw.reset_sound);
 soundlistener.addsoundevent(state.refreshing, r.raw.refreshing_sound);
 mpullrefreshlistview.setonpulleventlistener(soundlistener);
 }
 
 /**
 * 设置listview的适配器
 */
 private void initlistview() {
 //通过getrefreshableview()来得到一个listview对象
 actuallistview = mpullrefreshlistview.getrefreshableview();
 
 string []data = new string[] {"android","ios","wp","java","c++","c#"};
 mlistitems = new linkedlist<string>();
 //把string数组中的string添加到链表中
 mlistitems.addall(arrays.aslist(data));
 
 madapter = new arrayadapter<>(getapplicationcontext(), 
  android.r.layout.simple_list_item_1, mlistitems);
 actuallistview.setadapter(madapter);
 }
}

源码下载：http://xiazai.jb51.net/201609/yuanma/androidlistview(jb51.net).rar

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。