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Android编程:观察者模式设计

Android编程:观察者模式设计


本文博客链接:http://blog.csdn.net/jdh99,作者:jdh,转载请注明.


环境:

主机:WIN8

开发环境:Eclipse


说明:

1.打开sd卡中的xml文件,如果不存在,这新建一个,并写入默认配置

2.读取xml文件

3.Config_Info.java为配置信息数据结构

4.IF_Config.java为配置类的存取接口,其他类可以通过此接口直接获取配置信息

5.IF_Subject_Config.java为观察者模式目标类接口

6.IF_Observer_Config.java为观察者模式观察者类接口

7.Config.java为配置类,完成1,2两部工作,同时是观察者模式的目标类,一旦配置信息由变化着通知观察者类

8.TestClass.java为观察者模式的观察者


通过存取接口+观察者模式可以实现松耦合的设计。


xml文件格式:

<?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>

源代码:

Config_Info.java:

/**
 * 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;
}

IF_Config.java:

/**
 * 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();
}

IF_Subject_Config.java:

/**
 * 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();  

}

IF_Observer_Config.java:

/**
 * 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);

}

Config.java:

/**
 * 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();
		}
	}
}

TestClass.java:

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);
	}
}


MainActivity:

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


参考链接:

1.http://blog.csdn.net/crave_shy/article/details/21235855

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Android编程:观察者模式设计