開源項目PullToRefresh詳解

開源項地址：https://github.com/chrisbanes/Android-PullToRefresh

下拉刷新這個功能我們都比較常見了，今天介紹的就是這個功能的實現。我將按照這個開源庫的範例來一點一點介紹，今天是介紹比較常見的PullToRefreshListView，是讓listView有下拉刷新功能。

1.下載項目包，將library包導入即可，其他的包暫時不用

2.分析源碼，看我們可以設置的有哪些

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

    <declare-styleable name="PullToRefresh">

        <!-- A drawable to use as the background of the Refreshable View -->
        <!-- 設置刷新view的背景 -->
        <attr name="ptrRefreshableViewBackground" format="reference|color" />

        <!-- A drawable to use as the background of the Header and Footer Loading Views -->
        <!-- 設置頭部view的背景 -->
        <attr name="ptrHeaderBackground" format="reference|color" />

        <!-- Text Color of the Header and Footer Loading Views -->
        <!-- 設置頭部/底部文字的顏色 -->
        <attr name="ptrHeaderTextColor" format="reference|color" />

        <!-- Text Color of the Header and Footer Loading Views Sub Header -->
        <!-- 設置頭部/底部副標題的文字顏色 -->
        <attr name="ptrHeaderSubTextColor" format="reference|color" />

        <!-- Mode of Pull-to-Refresh that should be used -->
        <!-- 設置下拉刷新的模式，有多重方式可選。無刷新功能，從頂部刷新，從底部刷新，二者都有，只允許手動刷新 -->
        <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 -->
            <!-- 這兩個屬性不推薦了，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 -->
        <!-- 是否顯示指示箭頭 -->
        <attr name="ptrShowIndicator" format="reference|boolean" />

        <!-- Drawable to use as Loading Indicator. Changes both Header and Footer. -->
        <!-- 指示箭頭的圖片 -->
        <attr name="ptrDrawable" format="reference" />

        <!-- Drawable to use as Loading Indicator in the Header View. Overrides value set in ptrDrawable. -->
        <!-- 頂部指示箭頭的圖片，設置後會覆蓋ptrDrawable中頂部的設置 -->
        <attr name="ptrDrawableStart" format="reference" />

        <!-- Drawable to use as Loading Indicator in the Fooer View. Overrides value set in ptrDrawable. -->
        <!-- 底部指示箭頭的圖片，設置後會覆蓋ptrDrawable中底部的設置 -->
        <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 -->
        <!-- 設置文字的基本字體 -->
        <attr name="ptrHeaderTextAppearance" format="reference" />

        <!-- Base text color, typeface, size, and style for Header and Footer Loading Views Sub Header -->
        <!-- 設置副標題的基本字體 -->
        <attr name="ptrSubHeaderTextAppearance" format="reference" />

        <!-- Style of Animation should be used displayed when pulling. -->
        <!-- 設置下拉時標識圖的動畫，默認爲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 -->
        <!-- 設置刷新時是否允許滾動，一般爲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.
        -->
        <!-- 允許在listview中添加頭/尾視圖 -->
        <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.
        -->
        <!-- 當設置rotate時，可以用這個來設置刷新時旋轉的圖片 -->
        <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>

 

看到有這麼多可以設置的屬性，別以爲真的就可以定製了。真正要定製還得到layout中改變刷新佈局

 

3.開始用它建立自己的工程

設置佈局文件

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>

 

開始編寫代碼

1.找到這個控件，並且設置監聽器

這裏面用到了一個日期的工具類，其實就是設置上次下拉的時間的。此外在下拉後會觸發一個異步任務

    /**
     * 設置下拉刷新的listview的動作
     */
    private void initPTRListView() {
        mPullRefreshListView = (PullToRefreshListView) findViewById(R.id.pull_refresh_list);
        //設置拉動監聽器
        mPullRefreshListView.setOnRefreshListener(new OnRefreshListener<ListView>() {

            @Override
            public void onRefresh(PullToRefreshBase<ListView> refreshView) {
                //設置下拉時顯示的日期和時間
                String label = DateUtils.formatDateTime(getApplicationContext(), System.currentTimeMillis(),
                        DateUtils.FORMAT_SHOW_TIME | DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_ABBREV_ALL);

                // 更新顯示的label
                refreshView.getLoadingLayoutProxy().setLastUpdatedLabel(label);
                // 開始執行異步任務，傳入適配器來進行數據改變
                new GetDataTask(mPullRefreshListView, mAdapter,mListItems).execute();
            }
        });

        // 添加滑動到底部的監聽器
        mPullRefreshListView.setOnLastItemVisibleListener(new OnLastItemVisibleListener() {
            
            @Override
            public void onLastItemVisible() {
                Toast.makeText(getApplication(), "已經到底了", Toast.LENGTH_SHORT).show();
            }
        });
        
        //mPullRefreshListView.isScrollingWhileRefreshingEnabled();//看刷新時是否允許滑動
        //在刷新時允許繼續滑動
        mPullRefreshListView.setScrollingWhileRefreshingEnabled(true);
        //mPullRefreshListView.getMode();//得到模式
        //上下都可以刷新的模式。這裏有兩個選擇：Mode.PULL_FROM_START，Mode.BOTH，PULL_FROM_END
        mPullRefreshListView.setMode(Mode.BOTH);
        
        /**
         * 設置反饋音效
         */
        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.從上面的那個控件中，得到它包含的listView，並且設置適配器

    //普通的listview對象
    private ListView actualListView;
    //添加一個鏈表數組，來存放string數組，這樣就可以動態增加string數組中的內容了
    private LinkedList<String> mListItems;
    //給listview添加一個普通的適配器
    private ArrayAdapter<String> mAdapter;

 

這裏用到了一個LinkedList的對象，這個是一個類似於ArrayList的鏈表數組，比較方便在開頭和末尾添加String

    /**
     * 設置listview的適配器
     */
    private void initListView() {
        //通過getRefreshableView()來得到一個listview對象
        actualListView = mPullRefreshListView.getRefreshableView();
        
        String []data = new String[] {"android","ios","wp","java","c++","c#"};
        mListItems = new LinkedList<String>();
        //把string數組中的string添加到鏈表中
        mListItems.addAll(Arrays.asList(data));
        
        mAdapter = new ArrayAdapter<>(getApplicationContext(), 
                android.R.layout.simple_list_item_1, mListItems);
        actualListView.setAdapter(mAdapter);
    }

 

3.寫一個異步任務，來模仿從網絡加載數據

這裏要注意的是，加載完後要出發刷新完成和通知適配器改變的方法

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  :通過異步任務來加載網絡中的數據，進行更新
 * @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 自動生成的構造函數存根
        mPullRefreshListView = listView;
        mAdapter = adapter;
        mListItems = listItems;
    }
    
    @Override
    protected Void doInBackground(Void... params) {
        //模擬請求
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
        }
        return null;
    }
    
    @Override
    protected void onPostExecute(Void result) {
        // TODO 自動生成的方法存根
        super.onPostExecute(result);
        //得到當前的模式
        Mode mode = mPullRefreshListView.getCurrentMode();
        if(mode == Mode.PULL_FROM_START) {
            mListItems.addFirst("這是刷新出來的數據");
        }
        else {
            mListItems.addLast("這是刷新出來的數據");
        }
        // 通知數據改變了
        mAdapter.notifyDataSetChanged();
        // 加載完成後停止刷新
        mPullRefreshListView.onRefreshComplete();
        
    }
    


}

 

貼上acitivty中的全部代碼

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 {
    
    //一個可以下拉刷新的listView對象
    private PullToRefreshListView mPullRefreshListView;
    //普通的listview對象
    private ListView actualListView;
    //添加一個鏈表數組，來存放string數組，這樣就可以動態增加string數組中的內容了
    private LinkedList<String> mListItems;
    //給listview添加一個普通的適配器
    private ArrayAdapter<String> mAdapter;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        initView();

        //一打開應用就自動刷新，下面語句可以寫到刷新按鈕裏面
        mPullRefreshListView.setRefreshing(true);
        //new GetDataTask(mPullRefreshListView, mAdapter, mListItems).execute();
        //mPullRefreshListView.setRefreshing(false);

    }

    private void initView() {
        initPTRListView();
        initListView();
    }
    
    /**
     * 設置下拉刷新的listview的動作
     */
    private void initPTRListView() {
        mPullRefreshListView = (PullToRefreshListView) findViewById(R.id.pull_refresh_list);
        //設置拉動監聽器
        mPullRefreshListView.setOnRefreshListener(new OnRefreshListener<ListView>() {

            @Override
            public void onRefresh(PullToRefreshBase<ListView> refreshView) {
                //設置下拉時顯示的日期和時間
                String label = DateUtils.formatDateTime(getApplicationContext(), System.currentTimeMillis(),
                        DateUtils.FORMAT_SHOW_TIME | DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_ABBREV_ALL);

                // 更新顯示的label
                refreshView.getLoadingLayoutProxy().setLastUpdatedLabel(label);
                // 開始執行異步任務，傳入適配器來進行數據改變
                new GetDataTask(mPullRefreshListView, mAdapter,mListItems).execute();
            }
        });

        // 添加滑動到底部的監聽器
        mPullRefreshListView.setOnLastItemVisibleListener(new OnLastItemVisibleListener() {
            
            @Override
            public void onLastItemVisible() {
                Toast.makeText(getApplication(), "已經到底了", Toast.LENGTH_SHORT).show();
            }
        });
        
        //mPullRefreshListView.isScrollingWhileRefreshingEnabled();//看刷新時是否允許滑動
        //在刷新時允許繼續滑動
        mPullRefreshListView.setScrollingWhileRefreshingEnabled(true);
        //mPullRefreshListView.getMode();//得到模式
        //上下都可以刷新的模式。這裏有兩個選擇：Mode.PULL_FROM_START，Mode.BOTH，PULL_FROM_END
        mPullRefreshListView.setMode(Mode.BOTH);
        
        /**
         * 設置反饋音效
         */
        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);
    }
    
    /**
     * 設置listview的適配器
     */
    private void initListView() {
        //通過getRefreshableView()來得到一個listview對象
        actualListView = mPullRefreshListView.getRefreshableView();
        
        String []data = new String[] {"android","ios","wp","java","c++","c#"};
        mListItems = new LinkedList<String>();
        //把string數組中的string添加到鏈表中
        mListItems.addAll(Arrays.asList(data));
        
        mAdapter = new ArrayAdapter<>(getApplicationContext(), 
                android.R.layout.simple_list_item_1, mListItems);
        actualListView.setAdapter(mAdapter);
    }
}

 

源碼下載：http://download.csdn.net/detail/shark0017/8035465