检查更新是安卓app的常规功能，现在分享一下我做的检查更新的代码，事件触发为点击立即更新按钮。直接上代码：

        //创建ProgressDialog对象 m_pDialog = new ProgressDialog(UpdateActivity.this);	 	                // 设置进度条风格，风格为圆形，旋转的	                m_pDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);	 	                // 设置ProgressDialog 标题	                m_pDialog.setTitle("提示");	                	                // 设置ProgressDialog 提示信息	                m_pDialog.setMessage("正在下载最新的apk");	 	                // 设置ProgressDialog 的进度条是否不明确	                m_pDialog.setIndeterminate(false);	                	                // 设置ProgressDialog 是否可以按退回按键取消	                m_pDialog.setCancelable(true);	                	                // 让ProgressDialog显示	                m_pDialog.show();			new DownloadApkAsyncTask().execute("");

/***	 * 下载新版本apk并安装	 * @author zhangda	 *	 */	private class DownloadApkAsyncTask extends AsyncTask
    
     {		@Override		protected String doInBackground(String... paramArray) {			String httpUrl = Constant.URL_PREFIX + "app/mkb_" + newVersionName + ".apk";			final String fileName = "mkb_" + newVersionName + ".apk";			String path = Environment.getExternalStorageDirectory().getPath();            File tmpFile = new File(path + "/mkb");            if (!tmpFile.exists()) {                    tmpFile.mkdir();            }            file = new File(path + "/mkb/" + fileName);            try {                URL url = new URL(httpUrl);                HttpURLConnection conn = (HttpURLConnection) url.openConnection();                InputStream is = conn.getInputStream();                //计算文件长度                  int lenghtOfFile = conn.getContentLength();                  FileOutputStream fos = new FileOutputStream(file);                byte[] buf = new byte[1024];                conn.connect();                int len1 = 0;                  long total = 0;                  if (conn.getResponseCode() >= 400) {                        Toast.makeText(UpdateActivity.this, "连接超时", Toast.LENGTH_SHORT).show();                        m_pDialog.cancel();                } else {                    while ((len1 = is.read(buf)) > 0) {                          total += len1; //total = total + len1                        System.out.println((int)((total*100)/lenghtOfFile));                        publishProgress((int)((total*100)/lenghtOfFile));                          fos.write(buf, 0, len1);                    }                 }                conn.disconnect();                fos.close();                is.close();            } catch (MalformedURLException e) {                e.printStackTrace();            } catch (IOException e) {                e.printStackTrace();            }            return "";		}				@Override		protected void onPostExecute(String result) {			if(file != null){				m_pDialog.cancel();				Intent intent = new Intent();                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);                intent.setAction(android.content.Intent.ACTION_VIEW);                intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");                startActivity(intent);			}		}				@Override		protected void onProgressUpdate(Integer... values) {			super.onProgressUpdate(values);			System.out.println(values[0]);						if(values[0] < 100){				m_pDialog.setProgress(values[0]);			}			if(values[0] == 100){				m_pDialog.cancel();				UpdateActivity.this.finish();			}		}			}