Android在线自动更新的实现

//在main activity中调用

public class Main extends Activity{

String urls = "http://gdown.baidu.com/data/wisegame/f98d235e39e29031";//下载地址

UpdateManager manager = new UpdateManager(SplashActivity.this);
// 检查软件更新
manager.checkUpdate(urls);

}

public class UpdateManager {
    /* 下载中 */
    private static final int DOWNLOAD = 1;
    /* 下载结束 */
    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;

    private Context mContext;
    /* 更新进度条 */
    private ProgressBar mProgress;
    private Dialog mDownloadDialog;

    private Handler mHandler = new Handler()
    {
        public void handleMessage(Message msg)
        {
            switch (msg.what)
            {
                // 正在下载
                case DOWNLOAD:
                    // 设置进度条位置
                    mProgress.setProgress(progress);
                    break;
                case DOWNLOAD_FINISH:
                    // 安装文件
                    installApk();
                    break;
                default:
                    break;
            }
        };
    };
    String urls;
    public UpdateManager(Context context)
    {
        this.mContext = context;
    }

    /**
     * 检测软件更新
     */
    public void checkUpdate(String url)
    {
           urls = url;
        // 显示提示对话框
        showNoticeDialog();

    }



    /**
     * 获取软件版本号
     *
     * @param context
     * @return
     */
    private int getVersionCode(Context context)
    {
        int versionCode = 0;
        try
        {
            // 获取软件版本号，对应AndroidManifest.xml下android:versionCode
            versionCode = context.getPackageManager().getPackageInfo("com.szy.update", 0).versionCode;
        } catch (PackageManager.NameNotFoundException e)
        {
            e.printStackTrace();
        }
        return versionCode;
    }

    /**
     * 显示软件更新对话框
     */
    private void showNoticeDialog()
    {


        // 构造对话框
        AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
        builder.setTitle(R.string.soft_update_title);
        builder.setMessage(R.string.soft_update_info);
        builder.setCancelable(false);
        // 更新
        builder.setPositiveButton(R.string.soft_update_updatebtn, new DialogInterface.OnClickListener()
        {
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                dialog.dismiss();
                // 显示下载对话框
                showDownloadDialog();
            }
        });
        // 稍后更新
        builder.setNegativeButton(R.string.soft_update_later, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });
        Dialog noticeDialog = builder.create();
        noticeDialog.show();
    }

    /**
     * 显示软件下载对话框
     */
    private void showDownloadDialog()
    {
        // 构造软件下载对话框
        AlertDialog.Builder builder = new AlertDialog.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 v = inflater.inflate(R.layout.softupdate_progress, null);
        mProgress = (ProgressBar) v.findViewById(R.id.update_progress);
        builder.setView(v);
        // 取消更新
        builder.setNegativeButton(R.string.soft_update_cancel, new DialogInterface.OnClickListener()
        {
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                dialog.dismiss();
                // 设置取消状态
                cancelUpdate = true;
            }
        });
        mDownloadDialog = builder.create();
        mDownloadDialog.show();
        // 现在文件
        downloadApk();
    }

    /**
     * 下载apk文件
     */
    private void downloadApk()
    {
        // 启动新线程下载软件
        new downloadApkThread().start();
    }

    /**
     * 下载文件线程
     *
     * @author coolszy
     *@date 2012-4-26
     *@blog http://blog.92coding.com
     */
    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))
                {
                    // 获得存储卡的路径
                    String sdpath = Environment.getExternalStorageDirectory() + "/";
                    mSavePath = sdpath + "download";

                    URL url = new URL(urls);
                    // 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);
                    // 判断文件目录是否存在
                    if (!file.exists())
                    {
                        file.mkdir();
                    }
                    File apkFile = new File(mSavePath, "baidu_xinwen_1.1.0");//app名称
                    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,"baidu_xinwen_1.1.0");//app名称

        if (!apkfile.exists())
        {
            return;
        }
        // 通过Intent安装APK文件
        Intent i = new Intent(Intent.ACTION_VIEW);
        i.setDataAndType(Uri.parse("file://" + apkfile.toString()), "application/vnd.android.package-archive");
        mContext.startActivity(i);
    }
}