ANDROID_MARS学习笔记_S01原始版_020_Mp3player001_歌曲列表

一、项目设计

二、歌曲列表简介

1.利用java.net.HttpURLConnection以流的形式下载xml文件为String

2.自定义ContentHandler--》Mp3ListContentHandler

3.利用自定义的ContentHandler和javax.xml.parsers.SAXParserFactory生成org.xml.sax.XMLReader，用来处理下载的xml字符串，处理结果以List<Mp3Info>返回

4.以返回的List<Mp3Info>和布局文件创建android.widget.SimpleAdapter

5.最后在activity中调用setListAdapter(adapter)，完成更新列表操作

二、代码
1.xml
(1)main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout android:id="@+id/listLinearLayout"
        android:layout_width="fill_parent" android:layout_height="wrap_content"
        android:orientation="vertical">
        <ListView android:id="@id/android:list" android:layout_width="fill_parent"
            android:layout_height="wrap_content" android:drawSelectorOnTop="false"
            android:scrollbars="vertical" />
    </LinearLayout>
</LinearLayout>

(2)AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="tony.mp3player"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="21" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".Mp3ListActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
    <uses-permission android:name="android.permission.INTERNET"/>
</manifest>

3.mp3info_item.xml

<?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="horizontal"
    android:paddingLeft="10dip"
    android:paddingRight="10dip"
    android:paddingTop="1dip"
    android:paddingBottom="1dip"
    >
    <TextView android:id="@+id/mp3Name"
    android:layout_height="30dip"
    android:layout_width="180dip"
    android:textSize="10pt"/>
    <TextView android:id="@+id/mp3Size"
    android:layout_height="30dip"
    android:layout_width="180dip"
    android:textSize="10pt"/>
</LinearLayout>

2.java
(1)Mp3ListActivity.java

package tony.mp3player;

import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;

import tony.download.HttpDownloader;
import tony.model.Mp3Info;
import tony.xml.Mp3ListContentHandler;
import android.annotation.SuppressLint;
import android.app.ListActivity;
import android.os.Bundle;
import android.os.StrictMode;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.SimpleAdapter;

@SuppressLint("NewApi")
public class Mp3ListActivity extends ListActivity {
    private static final int UPDATE = 1;
    private static final int ABOUT = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        if (android.os.Build.VERSION.SDK_INT > 9) {
            StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
            StrictMode.setThreadPolicy(policy);
        }
        updateListView();
    }
    
    /**
     * 在用点击MENU按钮之后，会调用该方法，我们可以在这个方法当中加入自己的按钮控件
     */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        menu.add(0, UPDATE, UPDATE, R.string.mp3list_update);
        menu.add(0, ABOUT, ABOUT, R.string.mp3list_about);
        return super.onCreateOptionsMenu(menu);
    }
    
    /**
     * 当菜单选项被选中时调用
     */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        System.out.println("onOptionsItemSelected--->ItemId="+item.getItemId());
        switch (item.getItemId()) {
        case UPDATE:
            updateListView();
            break;
        case 2:
            break;
        default:
            break;
        }
        return super.onOptionsItemSelected(item);
    }
    
    private void updateListView() {
        String xml = downloadXML("http://192.168.1.104:8080/mp3/resources.xml");
        List<Mp3Info> infos = parse(xml);
        SimpleAdapter adapter = buidSimpleAdapter(infos);
        setListAdapter(adapter);
    }

    private SimpleAdapter buidSimpleAdapter(List<Mp3Info> infos) {
        // 生成一个List对象，并按照SimpleAdapter的标准，将mp3Infos当中的数据添加到List当中去
        List<HashMap<String, String>> list = new ArrayList<HashMap<String, String>>();
        HashMap<String,String> map = null;
        Mp3Info info = null;
        for(Iterator it = infos.iterator() ; it.hasNext() ;) {
            info = (Mp3Info) it.next();
            map = new HashMap<String,String>();
            map.put("mp3Name", info.getMp3Name());
            map.put("mp3Size", info.getMp3Size());
            list.add(map);
        }
        SimpleAdapter adapter = new SimpleAdapter(this, list, R.layout.mp3info_item, 
                new String[]{"mp3Name", "mp3Size"}, new int[]{R.id.mp3Name, R.id.mp3Size});
        return adapter;
    }

    private String downloadXML(String urlStr) {
        HttpDownloader httpDownloader = new HttpDownloader();
        String result = httpDownloader.download(urlStr);
        return result;
    }
    
    private List<Mp3Info> parse(String xml) {
        SAXParserFactory spf =  SAXParserFactory.newInstance();
        List<Mp3Info> infos = new ArrayList<Mp3Info>();
        try {
            XMLReader reader = spf.newSAXParser().getXMLReader();
            Mp3ListContentHandler handler = new Mp3ListContentHandler(infos);
            reader.setContentHandler(handler);
            reader.parse(new InputSource(new StringReader(xml)));
            for(Iterator it = infos.iterator();it.hasNext();) {
                Mp3Info info = (Mp3Info) it.next();
                System.out.println(info);
            }
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return infos;
    }
}

(2)Mp3ListContentHandler.java

package tony.xml;

import java.util.List;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import tony.model.Mp3Info;

public class Mp3ListContentHandler extends DefaultHandler {

    private List<Mp3Info> infos = null;
    private Mp3Info mp3Info = null;
    private String tagName = null;

    public Mp3ListContentHandler(List<Mp3Info> infos) {
        super();
        this.infos = infos;
    }

    @Override
    public void startDocument() throws SAXException {
        super.startDocument();
    }

    @Override
    public void endDocument() throws SAXException {
        super.endDocument();
    }

    @Override
    public void startElement(String uri, String localName, String qName,
            Attributes attributes) throws SAXException {
        this.tagName = localName;
        if(tagName.equals("resource")) {
            mp3Info = new Mp3Info();
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName)
            throws SAXException {
        if(qName.equals("resource")) {
            infos.add(mp3Info);
        }
        tagName = "";
    }

    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {
        String temp = new String(ch, start, length);
        if(tagName.equals("id")) 
            mp3Info.setId(temp);
        else if(tagName.equals("mp3.name"))
            mp3Info.setMp3Name(temp);
        else if(tagName.equals("mp3.size"))
            mp3Info.setMp3Size(temp);
        else if(tagName.equals("lrc.name"))
            mp3Info.setLrcName(temp);
        else if(tagName.equals("lrc.size"))
            mp3Info.setLrcSize(temp);
    }
}

(3)HttpDownloader.java

package tony.download;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpDownloader {

    /**
     * 根据URL下载文件，前提是这个文件当中的内容是文本，函数的返回值就是文件当中的内容
     * 1.创建一个URL对象
     * 2.通过URL对象，创建一个HttpURLConnection对象
     * 3.得到InputStram
     * 4.从InputStream当中读取数据
     * @param urlStr
     * @return
     */
    public String download(String urlStr) {
        StringBuffer sb = new StringBuffer();
        String line = null;
        BufferedReader buffer = null;
        try {
            // 创建一个URL对象
            URL url = new URL(urlStr);
            // 创建一个Http连接
            HttpURLConnection urlConn = (HttpURLConnection) url
                    .openConnection();
            // 使用IO流读取数据
            buffer = new BufferedReader(new InputStreamReader(urlConn
                    .getInputStream()));
            while ((line = buffer.readLine()) != null) {
                sb.append(line);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                buffer.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
}

(4)

package tony.model;

public class Mp3Info {

    private String id,mp3Name,mp3Size,lrcName,lrcSize;

    public Mp3Info() {
        super();
    }

    public Mp3Info(String id, String mp3Name, String mp3Size, String lrcName,
            String lrcSize) {
        super();
        this.id = id;
        this.mp3Name = mp3Name;
        this.mp3Size = mp3Size;
        this.lrcName = lrcName;
        this.lrcSize = lrcSize;
    }

    @Override
    public String toString() {
        return "Mp3Info [id=" + id + ", mp3Name=" + mp3Name + ", mp3Size="
                + mp3Size + ", lrcName=" + lrcName + ", lrcSize=" + lrcSize
                + "]";
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getMp3Name() {
        return mp3Name;
    }

    public void setMp3Name(String mp3Name) {
        this.mp3Name = mp3Name;
    }

    public String getMp3Size() {
        return mp3Size;
    }

    public void setMp3Size(String mp3Size) {
        this.mp3Size = mp3Size;
    }

    public String getLrcName() {
        return lrcName;
    }

    public void setLrcName(String lrcName) {
        this.lrcName = lrcName;
    }

    public String getLrcSize() {
        return lrcSize;
    }

    public void setLrcSize(String lrcSize) {
        this.lrcSize = lrcSize;
    }
    
    
}

四、运行结果