开源项目PullToRefresh详解（一）——PullToRefreshListView

  

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://download.csdn.net/detail/shark0017/8035465