Android观察者模式实例分析

<?xml version="1.0" encoding="UTF-8" standalone="true"?> -<config> <title>远程视频会见系统</title> <local_port>12600</local_port> <schedule_service_ip>10.58.1.59</schedule_service_ip><schedule_service_port>12601</schedule_service_port> </config>

/**  * 配置信息数据类型  * 新建时间:2014/12/8 by jdh  */ package com.example.helloanychat; public class Config_Info {  //标题  public String title;  //本机ip  public String local_ip;  //本机端口  public int local_port;  //调度服务器ip  public String schedule_server_ip;  //调度服务器端口  public int schedule_server_port; }

/**  * 接口：配置类，读写  * 新建时间:2014/12/8 by jdh  */ package com.example.helloanychat; public interface IF_Config {  public Config_Info get_config_info(); }

/**  * 接口：配置类，观察者模式:目标  * 新建时间：2014/12/8 by jdh  */ package com.example.helloanychat; public interface IF_Subject_Config {  public void register_observer(IF_Observer_Config observer);  public void remove_observer(IF_Observer_Config observer);  public void notify_observer(); }

/**  * 接口：配置类，观察者模式:观察者  * 新建时间：2014/12/8 by jdh  */ package com.example.helloanychat; public interface IF_Observer_Config {  public void update(Config_Info info); }

/**  * 配置信息类  * 新建日期:2014/12/8 by jdh  * 修改日期:2014/12/9 by jdh  */ package com.example.helloanychat; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.StringWriter; import java.net.Inet6Address; import java.net.InetAddress; import java.net.NetworkInterface; import java.net.SocketException; import java.util.ArrayList; import java.util.Enumeration; import java.util.List; import java.util.Timer; import java.util.TimerTask; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import android.os.Environment; import android.util.Log; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; import org.xmlpull.v1.XmlPullParserFactory; import org.xmlpull.v1.XmlSerializer; public class Config implements IF_Config,IF_Subject_Config {  //配置信息  private Config_Info Info = new Config_Info();  //存储观察者的列表  private List<IF_Observer_Config> Observers = new ArrayList<IF_Observer_Config>();  //定时器  private Timer Timer_Work = new Timer();  //工作间隔,单位:ms  private final int INTERVAL_WORK = 5000;  /**  * 构造函数  */  public Config() {  //生成配置信息  generate_config_info();  //创建定时线程  Timer_Work.schedule(new Task(),INTERVAL_WORK,INTERVAL_WORK); // 定时任务  }  //接口：读写  @Override  public Config_Info get_config_info() {  return Info;  }  //读写，观察者模式：目标  @Override  public void register_observer(IF_Observer_Config observer) {  Observers.add(observer);  }  @Override  public void remove_observer(IF_Observer_Config observer) {  int index = Observers.indexOf(observer);  if (index >= 0) {   Observers.remove(observer);  }  }  @Override  public void notify_observer() {  for (int i = 0; i < Observers.size(); i++) {   IF_Observer_Config o = (IF_Observer_Config) Observers.get(i);   o.update(Info);  }  }  /**  * 得到本机ip地址  * @return 本机ip地址  */  private String getLocalIpAddress() {  try {   for (Enumeration<NetworkInterface> en = NetworkInterface    .getNetworkInterfaces(); en.hasMoreElements();) {   NetworkInterface intf = en.nextElement();   for (Enumeration<InetAddress> enumIpAddr = intf    .getInetAddresses(); enumIpAddr.hasMoreElements();) {    InetAddress inetAddress = enumIpAddr.nextElement();    //if (!inetAddress.isLoopbackAddress()) {    if (!inetAddress.isLoopbackAddress() && !(inetAddress instanceof Inet6Address)) {    return inetAddress.getHostAddress().toString();    }   }   }  } catch (SocketException ex) {   Log.e("WifiPreference IpAddress", ex.toString());  }  return null;  }  /**  * 生成xml配置文件的String数据流  * Config_Info的本机ip信息不会保存  * @param info:配置信息  * @return xml的String数据流  */  private String produce_xml_string(Config_Info info) {  StringWriter stringWriter = new StringWriter();  try {   // 获取XmlSerializer对象   XmlPullParserFactory factory = XmlPullParserFactory.newInstance();   XmlSerializer xmlSerializer = factory.newSerializer();   // 设置输出流对象   xmlSerializer.setOutput(stringWriter);   //开始标签   xmlSerializer.startDocument("utf-8", true);   xmlSerializer.startTag(null, "config");   //标题   xmlSerializer.startTag(null, "title");   xmlSerializer.text(info.title);   xmlSerializer.endTag(null, "title");   //本机端口   xmlSerializer.startTag(null, "local_port");   xmlSerializer.text(Integer.toString(info.local_port));   xmlSerializer.endTag(null, "local_port");   //调度服务器ip   xmlSerializer.startTag(null, "schedule_service_ip");   xmlSerializer.text(info.schedule_server_ip);   xmlSerializer.endTag(null, "schedule_service_ip");   //调度服务器端口   xmlSerializer.startTag(null, "schedule_service_port");   xmlSerializer.text(Integer.toString(info.schedule_server_port));   xmlSerializer.endTag(null, "schedule_service_port");   xmlSerializer.endTag(null, "config");   xmlSerializer.endDocument();  } catch (Exception e) {   e.printStackTrace();  }  return stringWriter.toString();  }  /**  * 工作任务:得到配置信息  */  private void generate_config_info()  {  boolean ok;  File sd_path;  File file_cfg_dir;  File file_cfg;  FileOutputStream out;  String str;  FileInputStream in;  Config_Info info = new Config_Info();  //得到本机ip地址  info.local_ip = getLocalIpAddress();  //获取SD卡目录  sd_path = Environment.getExternalStorageDirectory();  //判断文件夹是否存在  file_cfg_dir = new File(sd_path.getPath() + "//Remote_Meeting");  if (!file_cfg_dir.exists() && !file_cfg_dir.isDirectory()) {   System.out.println("配置文件夹Remote_Meeting不存在!");   ok = file_cfg_dir.mkdirs();   if (ok) {   System.out.println("创建文件夹成功!");  } else {   System.out.println("创建文件夹失败!");  }  }  //判断配置文件是否存在  file_cfg = new File(file_cfg_dir.getPath(),"cfg.xml");  if (!file_cfg.exists())  {   System.out.println("配置文件cfg.xml不存在!");   try {   file_cfg.createNewFile();   System.out.println("创建文件cfg.xml成功!");   //生成初始化的配置数据   try {    out = new FileOutputStream(file_cfg);    //保存默认配置    Info.title = "远程视频会见系统";    Info.local_port = 12600;    Info.schedule_server_ip = "10.58.1.59";    Info.schedule_server_port = 12601;    str = produce_xml_string(Info);    out.write(str.getBytes());    out.close();    //保存本机ip    Info.local_ip = info.local_ip;    //通知观察者    notify_observer();   } catch (IOException e) {    // TODO Auto-generated catch block    e.printStackTrace();   }   } catch (IOException e) {   // TODO Auto-generated catch block   e.printStackTrace();   }  }  else  {   //解析xml文件   try {   in = new FileInputStream(file_cfg);   DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();   DocumentBuilder builder = factory.newDocumentBuilder();   Document document = builder.parse(in);   // 获取根节点   Element root = document.getDocumentElement();   NodeList node = root.getChildNodes();   //获得第1子节点:标题   info.title = node.item(0).getFirstChild().getNodeValue();   //获得第2子节点:本机端口   info.local_port = Integer.parseInt(node.item(1).getFirstChild().getNodeValue());   //获得第3子节点:调度服务器ip   info.schedule_server_ip = node.item(2).getFirstChild().getNodeValue();   //获得第4子节点:调度服务器端口   info.schedule_server_port = Integer.parseInt(node.item(3).getFirstChild().getNodeValue());   //判断配置信息是否变更   do   {    if (!info.title.equals(Info.title))    {    break;    }    if (!info.local_ip.equals(Info.local_ip))    {    break;    }    if (info.local_port != Info.local_port)    {    break;    }    if (!info.schedule_server_ip.equals(Info.schedule_server_ip))    {    break;    }    if (info.schedule_server_port != Info.schedule_server_port)    {    break;    }    //全部相同    return;   } while (false);   //赋值   Info.title = info.title;   Info.local_ip = info.local_ip;   Info.local_port = info.local_port;   Info.schedule_server_ip = info.schedule_server_ip;   Info.schedule_server_port = info.schedule_server_port;   //通知观察者   notify_observer();   } catch (Exception e) {   e.printStackTrace();   }  }  }  /**  * 定时器线程定时工作  */  private class Task extends TimerTask {  @Override  public void run() {   generate_config_info();  }  } }

package com.example.helloanychat; public class TestClass implements IF_Observer_Config {  public TestClass () {  }  @Override  public void update(Config_Info info) {  System.out.printf("-------------更新数据：%s,%s,%d,%s,%d/n",  info.title,info.local_ip,info.local_port,info.schedule_server_ip,info.schedule_server_port);  } }

TestClass testclass = new TestClass(); Config config = new Config(); mEditIP.setText(config.get_config_info().local_ip); config.register_observer(testclass);