Android研究之手PullToRefresh（ListView GridView 下拉刷新）使用具体解释



群里一哥们今天聊天偶然提到这个git hub上的控件：pull-to-refresh ，有兴趣的看下，样例中的功能极其强大，支持非常多控件。本篇博客具体给大家介绍下ListView和GridView利用pull-to-rerfesh 实现下拉刷新和上拉载入很多其它。对布局不清楚的能够看Android研究自己定义ViewGroup实现FlowLayout 具体解释。

1、ListView下拉刷新高速入门

pull-to-refresh对ListView进行了封装，叫做：PullToRefreshListView，使用方法和listview没什么差别，以下看demo.

布局文件：

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< 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" >        < 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 = "#00000000"          android : divider = "#19000000"          android : dividerHeight = "4dp"          android : fadingEdge = "none"          android : fastScrollEnabled = "false"          android : footerDividersEnabled = "false"          android : headerDividersEnabled = "false"          android : smoothScrollbar = "true" >      < / com . handmark . pulltorefresh . library . PullToRefreshListView >   < / RelativeLayout >

声明了一个PullToRefreshListView，里面全部的属性都是ListView的，没有不论什么其它属性，当然了PullToRefreshListView也提供了非常多配置的属性，后面会具体介绍。

Activity的代码:

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package com . example . zhy_pulltorefreash_chenyoca ;   import java . util . LinkedList ;   import android . app . Activity ; import android . os . AsyncTask ; import android . os . Bundle ; import android . text . format . DateUtils ; import android . widget . ArrayAdapter ; import android . widget . ListView ;   import com . handmark . pulltorefresh . library . PullToRefreshBase ; import com . handmark . pulltorefresh . library . PullToRefreshBase . OnRefreshListener ; import com . handmark . pulltorefresh . library . PullToRefreshListView ;   public class PullToRefreshListActivity extends Activity {        private LinkedList < String > mListItems ;      /**      * 上拉刷新的控件      */      private PullToRefreshListView mPullRefreshListView ;        private ArrayAdapter < String > mAdapter ;        private int mItemCount = 9 ;        @ Override      protected void onCreate ( Bundle savedInstanceState )      {          super . onCreate ( savedInstanceState ) ;          setContentView ( R . layout . activity_main ) ;          // 得到控件          mPullRefreshListView = ( PullToRefreshListView ) findViewById ( R . id . pull_refresh_list ) ;          //初始化数据          initDatas ( ) ;          //设置适配器          mAdapter = new ArrayAdapter < String > ( this ,                  android . R . layout . simple_list_item_1 , mListItems ) ;          mPullRefreshListView . setAdapter ( mAdapter ) ;          // 设置监听事件          mPullRefreshListView                  . setOnRefreshListener ( new OnRefreshListener < ListView > ( )                  {                      @ Override                      public void onRefresh (                              PullToRefreshBase < ListView > refreshView )                      {                          String label = DateUtils . formatDateTime (                                  getApplicationContext ( ) ,                                  System . currentTimeMillis ( ) ,                                  DateUtils . FORMAT_SHOW_TIME                                          | DateUtils . FORMAT_SHOW_DATE                                          | DateUtils . FORMAT_ABBREV_ALL ) ;                          // 显示最后更新的时间                          refreshView . getLoadingLayoutProxy ( )                                  . setLastUpdatedLabel ( label ) ;                            // 模拟载入任务                          new GetDataTask ( ) . execute ( ) ;                      }                  } ) ;        }        private void initDatas ( )      {          // 初始化数据和数据源          mListItems = new LinkedList < String > ( ) ;            for ( int i = 0 ; i < mItemCount ; i ++ )          {              mListItems . add ( "" + i ) ;          }      }        private class GetDataTask extends AsyncTask < Void , Void , String >      {            @ Override          protected String doInBackground ( Void . . . params )          {              try              {                  Thread . sleep ( 2000 ) ;              } catch ( InterruptedException e )              {              }              return "" + ( mItemCount ++ ) ;          }            @ Override          protected void onPostExecute ( String result )          {              mListItems . add ( result ) ;              mAdapter . notifyDataSetChanged ( ) ;              // Call onRefreshComplete when the list has been refreshed.              mPullRefreshListView . onRefreshComplete ( ) ;          }      }   }

代码极其简单，得到PullToRefreshListView控件，然后像ListView一样设置数据集。当然了，我们有下拉刷新，所以必须设置下拉刷新的回调：

setOnRefreshListener(new OnRefreshListener<ListView>(){}

我们在回调中模拟了一个异步任务，载入了一个Item。

效果图：

下拉时，运行我们的GetDataTask任务，任务运行完毕后在onPostExecute中调用mPullRefreshListView.onRefreshComplete();完毕刷新。

是不是分分钟实现下拉刷新。当然了，你可能会有疑问，下拉刷新的指示器上的文字能够自己定义吗？那个图片能够换成箭头吗？说好的上拉载入很多其它呢？后面会一一加入~

2、加入上拉载入很多其它

如过希望实现上拉载入很多其它，那么首先须要在布局文件的声明属性中加入一个属性，用于指定眼下的下拉模式：

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< 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" >        < 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 = "#00000000"          android : divider = "#19000000"          android : dividerHeight = "4dp"          android : fadingEdge = "none"          android : fastScrollEnabled = "false"          android : footerDividersEnabled = "false"          android : headerDividersEnabled = "false"          android : smoothScrollbar = "true"          ptr : ptrMode = "both" >      < / com . handmark . pulltorefresh . library . PullToRefreshListView >   < / RelativeLayout >

我们加入了一个属性：ptr:ptrMode=”both” ，意思：上拉和下拉都支持。

可选值为：disabled（禁用下拉刷新），pullFromStart（仅支持下拉刷新），pullFromEnd（仅支持上拉刷新），both（二者都支持），manualOnly（仅仅同意手动触发）

当然了，假设你不喜欢在布局文件里指定，全然能够使用代码设置，在onCreate里面写：mPullRefreshListView.setMode(Mode.BOTH);//设置你须要的模式

设置了模式为双向都支持，当然必须为上拉和下拉分别设置回调，请看以下的代码：

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package com . example . zhy_pulltorefreash_chenyoca ;   import java . util . LinkedList ;   import android . app . Activity ; import android . os . AsyncTask ; import android . os . Bundle ; import android . text . format . DateUtils ; import android . util . Log ; import android . widget . ArrayAdapter ; import android . widget . ListView ;   import com . handmark . pulltorefresh . library . PullToRefreshBase ; import com . handmark . pulltorefresh . library . PullToRefreshBase . Mode ; import com . handmark . pulltorefresh . library . PullToRefreshBase . OnRefreshListener ; import com . handmark . pulltorefresh . library . PullToRefreshBase . OnRefreshListener2 ; import com . handmark . pulltorefresh . library . PullToRefreshListView ;   public class PullToRefreshListActivity extends Activity {        private LinkedList < String > mListItems ;      /**      * 上拉刷新的控件      */      private PullToRefreshListView mPullRefreshListView ;        private ArrayAdapter < String > mAdapter ;        private int mItemCount = 9 ;        @ Override      protected void onCreate ( Bundle savedInstanceState )      {          super . onCreate ( savedInstanceState ) ;          setContentView ( R . layout . activity_main ) ;          // 得到控件          mPullRefreshListView = ( PullToRefreshListView ) findViewById ( R . id . pull_refresh_list ) ;          mPullRefreshListView . setMode ( Mode . BOTH ) ;          // 初始化数据          initDatas ( ) ;          // 设置适配器          mAdapter = new ArrayAdapter < String > ( this ,                  android . R . layout . simple_list_item_1 , mListItems ) ;          mPullRefreshListView . setAdapter ( mAdapter ) ;            mPullRefreshListView                  . setOnRefreshListener ( new OnRefreshListener2 < ListView > ( )                  {                      @ Override                      public void onPullDownToRefresh (                              PullToRefreshBase < ListView > refreshView )                      {                          Log . e ( "TAG" , "onPullDownToRefresh" ) ;                          //这里写下拉刷新的任务                          new GetDataTask ( ) . execute ( ) ;                      }                        @ Override                      public void onPullUpToRefresh (                              PullToRefreshBase < ListView > refreshView )                      {                          Log . e ( "TAG" , "onPullUpToRefresh" ) ;                          //这里写上拉载入很多其它的任务                          new GetDataTask ( ) . execute ( ) ;                      }                  } ) ;        }        private void initDatas ( )      {          // 初始化数据和数据源          mListItems = new LinkedList < String > ( ) ;            for ( int i = 0 ; i < mItemCount ; i ++ )          {              mListItems . add ( "" + i ) ;          }      }        private class GetDataTask extends AsyncTask < Void , Void , String >      {            @ Override          protected String doInBackground ( Void . . . params )          {              try              {                  Thread . sleep ( 2000 ) ;              } catch ( InterruptedException e )              {              }              return "" + ( mItemCount ++ ) ;          }            @ Override          protected void onPostExecute ( String result )          {              mListItems . add ( result ) ;              mAdapter . notifyDataSetChanged ( ) ;              // Call onRefreshComplete when the list has been refreshed.              mPullRefreshListView . onRefreshComplete ( ) ;          }      }

和第一段的代码仅仅有一个地方有差别，可能非常难发现：
mPullRefreshListView.setOnRefreshListener(new OnRefreshListener2<ListView>(){});注意这里的接口类型是OnRefreshListener2，多了个2，和上面的不一样，这个接口包括两个方法，一个上拉回调，一个下拉回调。好了，这样我们就成功加入了上拉与下拉，而且分别能够控制其回调代码。

效果图：

咋样，是不是也非常easy~注:假设你的上拉和下拉需求是运行一样的代码，那么你能够继续注冊OnRefreshListener接口，上拉和下拉都会运行同一个方法。

接下来介绍怎样使用带下拉刷新和载入很多其它的的GridView和自己定义样式~

3、带下拉和上拉的GridView ( PullToRefreshGridView )

相同的pull-to-refresh把GridView封装为：PullToRefreshGridView 。使用方法和PullToRefreshListView一摸一样~

首先看主布局文件：

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<? xml version = "1.0" encoding = "utf-8" ?> < LinearLayout xmlns : android = "http://schemas.android.com/apk/res/android"      android : layout_width = "fill_parent"      android : layout_height = "fill_parent"      android : orientation = "vertical" >        < ! -- The PullToRefreshGridView replaces a standard GridView widget . -- >        < com . handmark . pulltorefresh . library . PullToRefreshGridView          xmlns : ptr = "http://schemas.android.com/apk/res-auto"          android : id = "@+id/pull_refresh_grid"          android : layout_width = "fill_parent"          android : layout_height = "fill_parent"          android : columnWidth = "100dp"          android : gravity = "center_horizontal"          android : horizontalSpacing = "1dp"          android : numColumns = "auto_fit"          android : stretchMode = "columnWidth"          android : verticalSpacing = "1dp"          ptr : ptrDrawable = "@drawable/ic_launcher"          ptr : ptrMode = "both" / >   < / LinearLayout >

PullToRefreshGridView 的item的布局文件：

<?xml version="1.0" encoding="utf-8"?> <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/id_grid_item_text" android:layout_width="100dp" android:gravity="center" android:textColor="#ffffff" android:textSize="16sp" android:background="#000000" android:layout_height="100dp" />

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<? xml version = "1.0" encoding = "utf-8" ?> < TextView xmlns : android = "http://schemas.android.com/apk/res/android"      android : id = "@+id/id_grid_item_text"      android : layout_width = "100dp"      android : gravity = "center"      android : textColor = "#ffffff"      android : textSize = "16sp"      android : background = "#000000"      android : layout_height = "100dp" / >

接下来就是Activity的代码了：

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public class PullToRefreshGridActivity extends Activity {      private LinkedList < String > mListItems ;      private PullToRefreshGridView mPullRefreshListView ;      private ArrayAdapter < String > mAdapter ;        private int mItemCount = 10 ;        @ Override      protected void onCreate ( Bundle savedInstanceState )      {          super . onCreate ( savedInstanceState ) ;          setContentView ( R . layout . activity_ptr_grid ) ;          // 得到控件          mPullRefreshListView = ( PullToRefreshGridView ) findViewById ( R . id . pull_refresh_grid ) ;            // 初始化数据和数据源          initDatas ( ) ;            mAdapter = new ArrayAdapter < String > ( this , R . layout . grid_item ,                  R . id . id_grid_item_text , mListItems ) ;          mPullRefreshListView . setAdapter ( mAdapter ) ;            mPullRefreshListView                  . setOnRefreshListener ( new OnRefreshListener2 < GridView > ( )                  {                        @ Override                      public void onPullDownToRefresh (                              PullToRefreshBase < GridView > refreshView )                      {                          Log . e ( "TAG" , "onPullDownToRefresh" ) ; // Do work to                          String label = DateUtils . formatDateTime (                                  getApplicationContext ( ) ,                                  System . currentTimeMillis ( ) ,                                  DateUtils . FORMAT_SHOW_TIME                                          | DateUtils . FORMAT_SHOW_DATE                                          | DateUtils . FORMAT_ABBREV_ALL ) ;                            // Update the LastUpdatedLabel                          refreshView . getLoadingLayoutProxy ( )                                  . setLastUpdatedLabel ( label ) ;                                                   new GetDataTask ( ) . execute ( ) ;                      }                        @ Override                      public void onPullUpToRefresh (                              PullToRefreshBase < GridView > refreshView )                      {                          Log . e ( "TAG" , "onPullUpToRefresh" ) ; // Do work to refresh                                                              // the list here.                          new GetDataTask ( ) . execute ( ) ;                      }                  } ) ;      }        private void initDatas ( )      {          mListItems = new LinkedList < String > ( ) ;            for ( int i = 0 ; i < mItemCount ; i ++ )          {              mListItems . add ( i + "" ) ;          }      }        private class GetDataTask extends AsyncTask < Void , Void , Void >      {            @ Override          protected Void doInBackground ( Void . . . params )          {              try              {                  Thread . sleep ( 2000 ) ;              } catch ( InterruptedException e )              {              }              return null ;          }            @ Override          protected void onPostExecute ( Void result )          {              mListItems . add ( "" + mItemCount ++ ) ;              mAdapter . notifyDataSetChanged ( ) ;              // Call onRefreshComplete when the list has been refreshed.              mPullRefreshListView . onRefreshComplete ( ) ;          }      }

基本上上例没有不论什么差别，直接看效果图吧：

效果还是不错的，假设你比較细心会发现，那个下拉刷新的转圈的图片咋变成机器人了，那是由于我在布局文件中面设置了：

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< com . handmark . pulltorefresh . library . PullToRefreshGridView          ptr : ptrDrawable = "@drawable/ic_launcher"          . . .          / >

当然了这是旋转的效果，一般经常使用的还有，一个箭头倒置的效果，事实上也非常easy，一个属性：

ptr:ptrAnimationStyle=”flip”

去掉 ptr:ptrDrawable=”@drawable/ic_launcher”这个属性，假设你希望用下图默认的箭头，你也能够自己定义。

加入后，箭头就是这个样子：

ptr:ptrAnimationStyle的取值：flip（翻转动画）， rotate（旋转动画） 。

ptr:ptrDrawable则就是设置图标了。

4、自己定义下拉指示器文本内容等效果

能够在初始化完毕mPullRefreshListView后，通过mPullRefreshListView.getLoadingLayoutProxy()能够得到一个ILoadingLayout对象，这个对象能够设置各种指示器中的样式、文本等。

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ILoadingLayout startLabels = mPullRefreshListView                  . getLoadingLayoutProxy ( ) ;          startLabels . setPullLabel ( "你可劲拉，拉..." ) ; // 刚下拉时，显示的提示          startLabels . setRefreshingLabel ( "好嘞，正在刷新..." ) ; // 刷新时          startLabels . setReleaseLabel ( "你敢放，我就敢刷新..." ) ; // 下来达到一定距离时，显示的提示

假设你比較细心，会发现，前面我们设置上次刷新时间已经用到了：

// Update the LastUpdatedLabel
refreshView.getLoadingLayoutProxy().setLastUpdatedLabel(label);

如今的效果是：

默认是上拉和下拉的字同一时候改变的，假设我希望单独改变呢？

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private void initIndicator ( )      {          ILoadingLayout startLabels = mPullRefreshListView                  . getLoadingLayoutProxy ( true , false ) ;          startLabels . setPullLabel ( "你可劲拉，拉..." ) ; // 刚下拉时，显示的提示          startLabels . setRefreshingLabel ( "好嘞，正在刷新..." ) ; // 刷新时          startLabels . setReleaseLabel ( "你敢放，我就敢刷新..." ) ; // 下来达到一定距离时，显示的提示            ILoadingLayout endLabels = mPullRefreshListView . getLoadingLayoutProxy (                  false , true ) ;          endLabels . setPullLabel ( "你可劲拉，拉2..." ) ; // 刚下拉时，显示的提示          endLabels . setRefreshingLabel ( "好嘞，正在刷新2..." ) ; // 刷新时          endLabels . setReleaseLabel ( "你敢放，我就敢刷新2..." ) ; // 下来达到一定距离时，显示的提示      }

mPullRefreshListView.getLoadingLayoutProxy(true, false);接收两个參数，为true,false返回设置下拉的ILoadingLayout；为false,true返回设置上拉的。

5、经常使用的一些属性

当然了，pull-to-refresh在xml中还能定义一些属性：

ptrMode，ptrDrawable，ptrAnimationStyle这三个上面已经介绍过。

ptrRefreshableViewBackground 设置整个mPullRefreshListView的背景色

ptrHeaderBackground 设置下拉Header或者上拉Footer的背景色

ptrHeaderTextColor 用于设置Header与Footer中文本的颜色

ptrHeaderSubTextColor 用于设置Header与Footer中上次刷新时间的颜色

ptrShowIndicator假设为true会在mPullRefreshListView中出现icon，右上角和右下角，挺有意思的。

ptrHeaderTextAppearance ， ptrSubHeaderTextAppearance分别设置拉Header或者上拉Footer中字体的类型颜色等等。

ptrRotateDrawableWhilePulling当动画设置为rotate时，下拉是是否旋转。

ptrScrollingWhileRefreshingEnabled刷新的时候，是否同意ListView或GridView滚动。认为为true比較好。

ptrListViewExtrasEnabled 决定了Header，Footer以何种方式增加mPullRefreshListView，true为headView方式增加，就是滚动时刷新头部会一起滚动。

最后2个事实上对于用户体验还是挺重要的，假设设置的时候考虑下~。其它的属性自己选择就好。

注：上述属性非常多都能够代码控制，假设有须要能够直接mPullRefreshListView.set属性名 查看

以上为pull-to-refresh全部支持的属性~~

定义了一堆的效果：

右上、右下那个图标就是ptrShowIndicator。好了，大家能够依照自己的需求对着上面的属性解释配置。

在github上下载的样例，是依赖3个项目的，一个主要的library_pullToRefresh，一个PullToRefreshViewPager，一个PullToRefreshListFragment ；

上面介绍的样例仅仅依赖library_pullToRefresh，其它两个依赖不用导入。

好了，假设你认为本篇博客对你实用，就点个赞~留个言吧

源代码下载：zhy_pulltorefreash_chenyoca