Android - 软件自动更新的实现

那如何实现软件自动更新，具体过程：



效果图：







具体步骤：

1. 在服务器上部署更新所用的xml文件：version.xml

<update>
<version>2</version>
<name>baiduxinwen.apk</name>
<url>http://gdown.baidu.com/data/wisegame/e5f5c3b8e59401c8/baiduxinwen.apk</url>
</update>

2. 在客户端实现更新操作

涉及到三个技术：

1.xml文件的解析

2.HttpURLConnection连接

3.文件流I/O

这里创建一个解析xml文件的服务类:ParXmlService.java

package com.xiaowu.news.update;

import java.io.InputStream;
import java.util.HashMap;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class ParseXmlService {
public HashMap<String, String> parseXml (InputStream inStream) throws Exception{
HashMap<String, String> hashMap = new HashMap<String, String>();
//创建DocumentBuilderFactory，该对象将创建DocumentBuilder。
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
//创建DocumentBuilder，DocumentBuilder将实际进行解析以创建Document对象
DocumentBuilder builder = factory.newDocumentBuilder();
//解析该文件以创建Document对象
Document document = builder.parse(inStream);
//获取XML文件根节点
Element root = document.getDocumentElement();
//获得所有子节点
NodeList childNodes = root.getChildNodes();
for(int i = 0; i < childNodes.getLength(); i++) {
Node childNode = (Node) childNodes.item(i);
if(childNode.getNodeType() == Node.ELEMENT_NODE) {
Element childElement = (Element) childNode;
//版本号
if("version".equals(childElement.getNodeName())) {
hashMap.put("version", childElement.getFirstChild().getNodeValue());
//软件名称
} else if("name".equals(childElement.getNodeName())) {
hashMap.put("name", childElement.getFirstChild().getNodeValue());
//下载地址
} else if("url".equals(childElement.getNodeName())) {
hashMap.put("url", childElement.getFirstChild().getNodeValue());
}
}

}
return hashMap;
}
}

实现更新操作的管理类：UpdateManager.java

package com.xiaowu.news.update;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;

import javax.net.ssl.HttpsURLConnection;

import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.DialogInterface.OnClickListener;
import android.content.pm.PackageManager.NameNotFoundException;
import android.net.Uri;
import android.os.Environment;
import android.os.Handler;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ProgressBar;
import android.widget.Toast;

import com.xiaowu.news.R;

/**
*
* @author wwj
* @date 2012/11/17
* 实现软件更新的管理类
*/
public class UpdateManager {

//下载中...
private static final int DOWNLOAD = 1;
//下载完成
private static final int DOWNLOAD_FINISH = 2;
//保存解析的XML信息
HashMap<String , String> mHashMap;
//下载保存路径
private String mSavePath;
//记录进度条数量
private int progress;
//是否取消更新
private boolean cancelUpdate = false;
//上下文对象
private Context mContext;
//进度条
private ProgressBar mProgressBar;
//更新进度条的对话框
private Dialog mDownloadDialog;

private Handler mHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
switch(msg.what){
//下载中。。。
case DOWNLOAD:
//更新进度条
System.out.println(progress);
mProgressBar.setProgress(progress);
break;
//下载完成
case DOWNLOAD_FINISH:
// 安装文件
installApk();
break;
}
};
};

public UpdateManager(Context context) {
super();
this.mContext = context;
}

/**
* 检测软件更新
*/
public void checkUpdate() {
if (isUpdate()) {
//显示提示对话框
showNoticeDialog();
} else {
Toast.makeText(mContext, R.string.soft_update_no, Toast.LENGTH_SHORT).show();
}

}

private void showNoticeDialog() {
// TODO Auto-generated method stub
//构造对话框
AlertDialog.Builder builder = new Builder(mContext);
builder.setTitle(R.string.soft_update_title);
builder.setMessage(R.string.soft_update_info);
//更新
builder.setPositiveButton(R.string.soft_update_updatebtn, new OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.dismiss();
// 显示下载对话框
showDownloadDialog();
}
});
// 稍后更新
builder.setNegativeButton(R.string.soft_update_later, new OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.dismiss();
}
});
Dialog noticeDialog = builder.create();
noticeDialog.show();
}

private void showDownloadDialog() {
// 构造软件下载对话框
AlertDialog.Builder builder = new Builder(mContext);
builder.setTitle(R.string.soft_updating);
// 给下载对话框增加进度条
final LayoutInflater inflater = LayoutInflater.from(mContext);
View view = inflater.inflate(R.layout.softupdate_progress, null);
mProgressBar = (ProgressBar) view.findViewById(R.id.update_progress);
builder.setView(view);
builder.setNegativeButton(R.string.soft_update_cancel, new OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.dismiss();
// 设置取消状态
cancelUpdate = true;
}
});
mDownloadDialog = builder.create();
mDownloadDialog.show();
//下载文件
downloadApk();
}

/**
* 下载APK文件
*/
private void downloadApk() {
// TODO Auto-generated method stub
// 启动新线程下载软件
new DownloadApkThread().start();
}

/**
* 检查软件是否有更新版本
* @return
*/
public boolean isUpdate() {
// 获取当前软件版本
int versionCode = getVersionCode(mContext);
//把version.xml放到网络上，然后获取文件信息
InputStream inStream = ParseXmlService.class.getClassLoader().getResourceAsStream("version.xml");
// 解析XML文件。 由于XML文件比较小，因此使用DOM方式进行解析
ParseXmlService service = new ParseXmlService();
try {
mHashMap = service.parseXml(inStream);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
if(null != mHashMap) {
int serviceCode = Integer.valueOf(mHashMap.get("version"));
//版本判断
if(serviceCode > versionCode) {
return true;
}
}
return false;
}

/**
* 获取软件版本号
* @param context
* @return
*/
private int getVersionCode(Context context) {
// TODO Auto-generated method stub
int versionCode = 0;

// 获取软件版本号，对应AndroidManifest.xml下android:versionCode
try {
versionCode = context.getPackageManager().getPackageInfo(
"com.xiaowu.news", 0).versionCode;
} catch (NameNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return versionCode;
}

/**
* 下载文件线程
* @author Administrator
*
*/
private class DownloadApkThread extends Thread {
@Override
public void run() {
try
{
//判断SD卡是否存在，并且是否具有读写权限
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))
{
// 获取SDCard的路径
String sdpath = Environment.getExternalStorageDirectory() + "/";
mSavePath = sdpath + "download";
URL url = new URL(mHashMap.get("url"));
// 创建连接
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.connect();
// 获取文件大小
int length = conn.getContentLength();
// 创建输入流
InputStream is = conn.getInputStream();

File file = new File(mSavePath);
// 如果文件不存在，新建目录
if (!file.exists())
{
file.mkdir();
}
File apkFile = new File(mSavePath, mHashMap.get("name"));
FileOutputStream fos = new FileOutputStream(apkFile);
int count = 0;
// 缓存
byte buf[] = new byte[1024];
// 写入到文件中
do
{
int numread = is.read(buf);
count += numread;
// 计算进度条的位置
progress = (int) (((float) count / length) * 100);
// 更新进度
mHandler.sendEmptyMessage(DOWNLOAD);
if (numread <= 0)
{
// 下载完成
mHandler.sendEmptyMessage(DOWNLOAD_FINISH);
break;
}
// 写入文件
fos.write(buf, 0, numread);
} while (!cancelUpdate);//点击取消就停止下载
fos.close();
is.close();
}
} catch (MalformedURLException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
// 取消下载对话框显示
mDownloadDialog.dismiss();
}
}

/**
* 安装APK文件
*/
private void installApk()
{
File apkfile = new File(mSavePath, mHashMap.get("name"));
if (!apkfile.exists())
{
return;
}
Intent i = new Intent(Intent.ACTION_VIEW);
i.setDataAndType(Uri.parse("file://" + apkfile.toString()), "application/vnd.android.package-archive");
mContext.startActivity(i);
}
}

参考：http://blog.csdn.net/wwj_748/article/details/8195565

　　 http://blog.csdn.net/android_tutor/article/details/7015986