mp3播放器（三）（代码重构）

package com.example.mp3player00;

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 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 xml.Mp3ListContentHandler;

import model.Mp3Info;

import com.example.download.HttpDownloader;

import android.os.Bundle;
import android.app.Activity;
import android.app.ListActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.SimpleAdapter;

public class Mp3ListActivity extends ListActivity {
    private static final int upadate=1;
    private static final int about=2;
   //以上定义常量，看到值的名字就知道按钮的名字    
   //且为后面修改提供方便
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mp3_list);
        updateListView();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_mp3_list, menu);
        menu.add(0, 1, 1,R.string.mp3list_update);
        menu.add(0, 2, 2, R.string.mp3list_about);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        //System.out.println("--->"+item.getItemId());
        if(item.getItemId()==upadate)
        {
            updateListView();
            
            
        }
        else if(item.getItemId()==about)
        {
            //用户点击了关于按钮
        }
        return super.onOptionsItemSelected(item);
    }
    private void updateListView(){
        //用户点击了更新按钮
        
        String xml=downloadXML("http://192.168.1.100:8080/mp3/resources.xml");
        //System.out.println("----->"+xml);
        
            List<Mp3Info> mp3infos = null;
            try {
                mp3infos = parse(xml);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }//List<Mp3Info>可以看出一个int，String这样一个类型
            //构建Adapter，首先生成一个List对象。List对象里面存的是HashMap，HashMap里面存的是String
        
            List<HashMap<String,String>> list=new ArrayList<HashMap<String,String>>();
           //将Mp3Info迭代出来
            for (Iterator iterator = mp3infos.iterator(); iterator.hasNext();) {
                Mp3Info mp3Info = (Mp3Info) iterator.next();
                 //生成一个HashMap对象
                HashMap<String,String> map=new HashMap<String,String>();
                //构造一个map
                map.put("mp3_name", mp3Info.getMp3Name());
                map.put("mp3_size", mp3Info.getMp3Size());
                //构造好map后添加到List中，即将HashMap添加到List中
                list.add(map);
            }
            //生成adapter
            SimpleAdapter simpleAdapter=
new SimpleAdapter(this,list,R.layout.mp3info_item,new String[]{"mp3_name","mp3_size"},new int[]{R.id.mp3_name,R.id.mp3_size});
            setListAdapter(simpleAdapter);
            
    }
    //写一个单独的下载函数，更加清晰
    private String downloadXML(String urlStr) 
    {
        
        HttpDownloader httpdownloader=new HttpDownloader(); 
        String result=httpdownloader.download(urlStr);
        return result;
    }
    //在这个函数中解析xml
    //首先生成xml解析器
    private List<Mp3Info> parse(String xmlStr) throws IOException 
    {
        List<Mp3Info> info=new ArrayList<Mp3Info>();
        SAXParserFactory saxParserFactory=SAXParserFactory.newInstance();
        try {
            XMLReader xmlReader=saxParserFactory.newSAXParser().getXMLReader();            
            Mp3ListContentHandler  mp3ListContentHandler=new Mp3ListContentHandler(info);
            xmlReader.setContentHandler(mp3ListContentHandler);
            xmlReader.parse(new InputSource(new StringReader(xmlStr)));
            //解析完数据都天道info里面，然后用for循环迭代出来
            for (Iterator iterator = info.iterator(); iterator.hasNext();) {
                Mp3Info mp3Info = (Mp3Info) iterator.next();
                System.out.println(mp3Info);
            }
            
            
        } catch (SAXException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ParserConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return info;
    
    }

}


将updateListView()继续重构

  1 package com.example.mp3player00;
  2 
  3 import java.io.IOException;
  4 import java.io.StringReader;
  5 import java.util.ArrayList;
  6 import java.util.HashMap;
  7 import java.util.Iterator;
  8 import java.util.List;
  9 
 10 import javax.xml.parsers.ParserConfigurationException;
 11 import javax.xml.parsers.SAXParserFactory;
 12 
 13 import org.xml.sax.InputSource;
 14 import org.xml.sax.SAXException;
 15 import org.xml.sax.XMLReader;
 16 
 17 import xml.Mp3ListContentHandler;
 18 
 19 import model.Mp3Info;
 20 
 21 import com.example.download.HttpDownloader;
 22 
 23 import android.os.Bundle;
 24 import android.app.Activity;
 25 import android.app.ListActivity;
 26 import android.view.Menu;
 27 import android.view.MenuItem;
 28 import android.widget.SimpleAdapter;
 29 
 30 public class Mp3ListActivity extends ListActivity {
 31     private static final int upadate=1;
 32     private static final int about=2;
 33    //以上定义常量，看到值的名字就知道按钮的名字    
 34    //且为后面修改提供方便
 35     @Override
 36     protected void onCreate(Bundle savedInstanceState) {
 37         super.onCreate(savedInstanceState);
 38         setContentView(R.layout.activity_mp3_list);
 39         updateListView();
 40     }
 41 
 42     @Override
 43     public boolean onCreateOptionsMenu(Menu menu) {
 44         // Inflate the menu; this adds items to the action bar if it is present.
 45         getMenuInflater().inflate(R.menu.activity_mp3_list, menu);
 46         menu.add(0, 1, 1,R.string.mp3list_update);
 47         menu.add(0, 2, 2, R.string.mp3list_about);
 48         return true;
 49     }
 50 
 51     @Override
 52     public boolean onOptionsItemSelected(MenuItem item) {
 53         // TODO Auto-generated method stub
 54         //System.out.println("--->"+item.getItemId());
 55         if(item.getItemId()==upadate)
 56         {
 57             updateListView();
 58             
 59             
 60         }
 61         else if(item.getItemId()==about)
 62         {
 63             //用户点击了关于按钮
 64         }
 65         return super.onOptionsItemSelected(item);
 66     }
 67     private SimpleAdapter buildSimpleAdapter(List<Mp3Info> mp3infos){
 68         //构建Adapter，首先生成一个List对象。List对象里面存的是HashMap，HashMap里面存的是String
 69         
 70         List<HashMap<String,String>> list=new ArrayList<HashMap<String,String>>();
 71         //将Mp3Info迭代出来
 72         for (Iterator iterator = mp3infos.iterator(); iterator.hasNext();) {
 73             Mp3Info mp3Info = (Mp3Info) iterator.next();
 74              //生成一个HashMap对象
 75             HashMap<String,String> map=new HashMap<String,String>();
 76             //构造一个map
 77             map.put("mp3_name", mp3Info.getMp3Name());
 78             map.put("mp3_size", mp3Info.getMp3Size());
 79             //构造好map后添加到List中，即将HashMap添加到List中
 80             list.add(map);
 81         }
 82         //生成adapter
 83         SimpleAdapter simpleAdapter=
   new SimpleAdapter(this,list,R.layout.mp3info_item,new String[]{"mp3_name","mp3_size"},new int[]{R.id.mp3_name,R.id.mp3_size});
 84         
 85         
 86         return simpleAdapter;
 87         
 88     }
 89     private void updateListView(){
 90         //用户点击了更新按钮
 91         
 92         String xml=downloadXML("http://192.168.1.100:8080/mp3/resources.xml");
 93         //System.out.println("----->"+xml);
 94         
 95             List<Mp3Info> mp3infos = null;
 96             try {
 97                 mp3infos = parse(xml);
 98             } catch (IOException e) {
 99                 // TODO Auto-generated catch block
100                 e.printStackTrace();
101             }//List<Mp3Info>可以看出一个int，String这样一个类型
102             SimpleAdapter simpleAdapter=buildSimpleAdapter(mp3infos);
103             setListAdapter(simpleAdapter);
104             
105     }
106     //写一个单独的下载函数，更加清晰
107     private String downloadXML(String urlStr) 
108     {
109         
110         HttpDownloader httpdownloader=new HttpDownloader(); 
111         String result=httpdownloader.download(urlStr);
112         return result;
113     }
114     //在这个函数中解析xml
115     //首先生成xml解析器
116     private List<Mp3Info> parse(String xmlStr) throws IOException 
117     {
118         List<Mp3Info> info=new ArrayList<Mp3Info>();
119         SAXParserFactory saxParserFactory=SAXParserFactory.newInstance();
120         try {
121             XMLReader xmlReader=saxParserFactory.newSAXParser().getXMLReader();            
122             Mp3ListContentHandler  mp3ListContentHandler=new Mp3ListContentHandler(info);
123             xmlReader.setContentHandler(mp3ListContentHandler);
124             xmlReader.parse(new InputSource(new StringReader(xmlStr)));
125             //解析完数据都天道info里面，然后用for循环迭代出来
126             for (Iterator iterator = info.iterator(); iterator.hasNext();) {
127                 Mp3Info mp3Info = (Mp3Info) iterator.next();
128                 System.out.println(mp3Info);
129             }
130             
131             
132         } catch (SAXException e) {
133             // TODO Auto-generated catch block
134             e.printStackTrace();
135         } catch (ParserConfigurationException e) {
136             // TODO Auto-generated catch block
137             e.printStackTrace();
138         }
139         return info;
140     
141     }
142 
143 }
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原文地址：https://www.cnblogs.com/kyxyes/p/3364470.html