Android Podcast Code Source

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Android Podcast player

工程目录：

UI设计：

UI设计部分只做了简单修改：

在TextView1下面由添加了一个TextView2
imageView中删除了android:src="@raw/pic"

布局效果：

UI布局详细代码

工程代码

wikipodcast2.java package com.emsym.wikipodcast2;  import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.util.Iterator; import java.util.LinkedList; import java.util.List;  import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException;  import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.SAXException;  import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.media.MediaPlayer; import android.media.MediaPlayer.OnCompletionListener; import android.net.Uri; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ImageView; import android.widget.ProgressBar; import android.widget.SeekBar; import android.widget.SeekBar.OnSeekBarChangeListener; import android.widget.TextView;类成员定义：（有点类似全局变量定义）   TextView mTextView;   TextView itemTextView;   Button startButton;   Button pauseButton;   Button nextButton;   ProgressBar mProgressBar;   SeekBar mSeekBar;   ImageView mImageView;      MediaPlayer mMediaPlayer;      int mVol = 50;      List<Item> itemList = new LinkedList<Item>();   Iterator it;在OnCreat方法中：setContentView()：显示UI布局main.xmlwidgetsConfigure()：实例化使用的各种窗口部件并进行相应配置（主要是设置各种事件监听器）XMLDOM()：使用DOM对xml文件进行解析   @Override   public void onCreate(Bundle savedInstanceState) {        String uri = "http://www.voiceblog.jp/katsuhiro/rss2.0.xml";     super.onCreate(savedInstanceState);     setContentView(R.layout.main);            widgetsConfigure();                  XMLDOM(uri);        }widgetsConfigure()实例化了各种窗口部件并设置事件监听器，并声明了新建了mMediaPlayer。   public void widgetsConfigure(){      startButton = (Button) findViewById (R.id.startButton);       startButton.setOnClickListener(startButtonClicked);              pauseButton = (Button) findViewById (R.id.pauseorcontinueButton);       pauseButton.setOnClickListener(pauseButtonClicked);              nextButton = (Button) findViewById (R.id.nextButton);       nextButton.setOnClickListener(nextButtonClicked);              mSeekBar = (SeekBar) findViewById (R.id.VolumeSeekBar);       mSeekBar.setOnSeekBarChangeListener(mSeekBarChanged);              mTextView = (TextView) findViewById (R.id.TextView1);       mTextView.setText("Click start to play!");              itemTextView = (TextView) findViewById (R.id.TextView2);              mProgressBar = (ProgressBar) findViewById (R.id.MusicProgressBar);       mImageView = (ImageView) findViewById (R.id.musicImage);              mMediaPlayer = new MediaPlayer();          }startButton点击事件监听器设置 public OnClickListener startButtonClicked = new OnClickListener(){    @Override   public void onClick(View v) {     // TODO Auto-generated method stub     it = itemList.iterator();     if(it.hasNext()){       Item ilist = (Item) it.next();       PlayMusic(ilist);            }   } };it = itemList.iterator();构建一个链表的迭代器；调用函数PlayMusic()来播放音乐。mMediaPlayer播放结束事件监听器设置 public OnCompletionListener completedPlay = new OnCompletionListener(){   public void onCompletion(MediaPlayer arg0){      PlayNext();   } };当播放结束事件被监听到时，则调用函数PlayNext()来播放下一首函数PlayNext():播放下一首 public void PlayNext(){   if(it.hasNext()){     Item ilist = (Item)it.next();     PlayMusic(ilist);   }else{     it = itemList.iterator();     Item ilist = (Item)it.next();     PlayMusic(ilist);   } }播放下一首，首先判断itemList是否还有下一个Item，如果有，则去下一个Item播放；如果没有，则重置迭代器（从头开始），选择第一个Item来播放函数PlayMusic():开始播放音乐 public void PlayMusic(Item music){      itemTextView.setText("Title: "+music.title+"\n");   itemTextView.append("Authot: "+ music.author+"\n");   itemTextView.append("PubDate: "+ music.pubDate+"\n");   itemTextView.append("Duration: "+ music.duration+"\n");      Uri uri = Uri.parse(music.url);   mMediaPlayer.reset(); //**   try{     mMediaPlayer.setDataSource(this, uri);     mSeekBar.setProgress(mVol);     mMediaPlayer.setVolume((float)(0.01*mVol), (float)(0.01*mVol));   }catch(IllegalStateException e){   }catch(IOException e){   }catch(IllegalArgumentException e){   }catch(SecurityException e){   }      try{     mMediaPlayer.prepare();   }catch(IOException e){   }      mMediaPlayer.start();   mMediaPlayer.setOnCompletionListener(completedPlay);      changeProgressBar();    }该函数的参数是Item，首先是取出Item中的各个变量，对一些变量进行显示；然后设置播放的数据源，并调节播放音量和拖动条显示；设置播放结束事件监听器；调用函数changeProgressBar()来改变进度条显示；函数changeProgressBar()：新建线程负责改变进度条 public void changeProgressBar(){   mProgressBar.setMax(mMediaPlayer.getDuration());   new Thread(new Runnable(){     public void run(){       while(true){         mProgressBar.setProgress(mMediaPlayer.getCurrentPosition());         try {           Thread.sleep(1000);         } catch (InterruptedException e) {           // TODO Auto-generated catch block         }        }     }   }).start(); }新建一个线程，根据方法getCurrentPosition()得到的结果来设置进度条的进度pauseButton点击事件监听器设置 public OnClickListener pauseButtonClicked = new OnClickListener(){    @Override   public void onClick(View v) {     // TODO Auto-generated method stub        if(mMediaPlayer.isPlaying()){       mMediaPlayer.pause();       pauseButton.setText("continue");     }else{       mMediaPlayer.start();       pauseButton.setText("pause");     }   } };nextButton点击事件监听器设置 public OnClickListener nextButtonClicked = new OnClickListener(){    @Override   public void onClick(View v) {     // TODO Auto-generated method stub          PlayNext();   }   };这个的设置和播放一首结束时一样mSeekBar改变事件监听器设置 public OnSeekBarChangeListener mSeekBarChanged = new OnSeekBarChangeListener(){    @Override   public void onProgressChanged(SeekBar seekBar, int progress,                                    boolean fromUser) {     // TODO Auto-generated method stub          mVol = progress;     mMediaPlayer.setVolume((float)(0.01*mVol), (float)(0.01*mVol));   }      @Override   public void onStartTrackingTouch(SeekBar seekBar) {     // TODO Auto-generated method stub        }      @Override   public void onStopTrackingTouch(SeekBar seekBar) {     // TODO Auto-generated method stub        }      };函数XMLDOM()：对xml文件的DOM解析 public void XMLDOM(String xmlUri){      DocumentBuilderFactory docBuilderFactory = null;   DocumentBuilder docBuilder = null;   Document doc = null;      String TITLE = "title";   String IMAGE = "itunes:image";   String ITEM = "item";      try{     docBuilderFactory = DocumentBuilderFactory.newInstance();     docBuilder = docBuilderFactory.newDocumentBuilder();     doc = docBuilder.parse(xmlUri);        Element root = doc.getDocumentElement();     //title     Node title = root.getElementsByTagName(TITLE).item(0);     mTextView.setText(title.getTextContent());        //image     Node image = root.getElementsByTagName(IMAGE).item(0);     Element elementImage = (Element) image;     String imageUrl =elementImage.getAttribute("href");     mImageView.setImageBitmap(GetNetBitmap(imageUrl));        //Items     NodeList items = root.getElementsByTagName(ITEM);     for(int i = 0;i<items.getLength();i++){       Node item = items.item(i);       Item music = new Item();       NodeList elements =item.getChildNodes();       for(int j=0;j<elements.getLength();j++){         Node tag = elements.item(j);         if(tag.getNodeName()!= "#text"){           if(tag.getNodeName().equals("title")) music.title = tag.getTextContent();           if(tag.getNodeName().equals("pubDate")) music.pubDate = tag.getTextContent();           if(tag.getNodeName().equals("itunes:duration")) music.duration = tag.getTextContent();           if(tag.getNodeName().equals("author")) music.author = tag.getTextContent();           if(tag.getNodeName().equals("enclosure")){             Element tagEnclosure = (Element) tag;             music.url = tagEnclosure.getAttribute("url");           }         }       }       itemList.add(music);     }   }catch(ParserConfigurationException e){   }catch(SAXException e){   }catch(IOException e){   }       }对于XML的解析，需要明确几个概念：Element，Node，NodeList，了解它们用法。详细介绍请参见XML介绍明确了以上几个概念，相信对上述代码的理解就很容易了。函数GetNetBitmap()：获取网络图片 public Bitmap GetNetBitmap(String url) {   URL myFileUrl = null;   Bitmap bitmap = null;   try {     myFileUrl = new URL(url);   }catch(MalformedURLException e) {   }   try {     HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection();     conn.setDoInput(true);     conn.connect();     InputStream is = conn.getInputStream();     bitmap = BitmapFactory.decodeStream(is);     is.close();   }catch(IOException e) {   }   return bitmap; }

AndroidManifest.xml

由于在程序中是用了网络，所以在AndroidManifest.xml中要添加使用网络的user-permission,使用方法：

 <uses-permission android:name="android.permission.INTERNET" />

mediaplayer实现音乐播放

Android Podcast Code Source

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