Android应用自动更新功能实现使用AsyncTask!

我所开发应用不是面向大众的应用,所以无法放到应用市场去让大家下载,然后通过应用市场更新.所以我必要做一个应用自动更新功能.但是不难,Thanks to下面这篇博客:


Android应用自动更新功能的实现！！！


如果你是以前没有做过此类功能,建议你先看上面的文章.然后再来看我的.因为我也是参考了上面的实现.



 其实这个自动更新功能大体就是两个三个步骤:


  (1)检查更新


  (2)下载更新


 (3)安装更新  


   检查更新和下载更新其实可以算是一步.因为都比较简单,都是主要是下载.


   1) 当你有新的版本发布时,在一个位置放一个更新的文件.


里面到少放有最新应用的版本号.然后你拿当前应用的版本号和服务器上的版本号对比,就知道要不要下载更新了.


  2 ) 下载这个过程,对于Java来说不是什么难事,因为Java提供了丰富的API.更何况Android内置了HttpClient可用.


  3) 这个,安装过程,其实就是使用一个打开查看此下载文件的 Intent.






 这时需要考虑的是文件下载后放到哪里,安全否.:

一般就是先检测SD卡.然后选择一个合适的目录.

private void checkUpdate() {    RequestFileInfo requestFileInfo = new RequestFileInfo();    requestFileInfo.fileUrl = "http://www.waitab.com/demo/demo.apk";    String status = Environment.getExternalStorageState();    if (!Environment.MEDIA_MOUNTED.equals(status)) {        ToastUtils.showFailure(getApplicationContext(),                "SDcard cannot use!");        return;    }    requestFileInfo.saveFilePath = Environment            .getExternalStoragePublicDirectory(                    Environment.DIRECTORY_DOWNLOADS).getAbsolutePath();    requestFileInfo.saveFileName = "DiTouchClient.apk";    showHorizontalFragmentDialog(R.string.title_wait,            R.string.title_download_update);    new DownlaodUpdateTask().execute(requestFileInfo);}

上面的进度条显示我已经封装好的了.showHorizontalFragmentDialog()

显然我使用了android-support-v4兼容包来使用Fragment的.

  在进度条中有显示,下载文件大小,已经下载了多少.速度等信息.

   由于涉及到网络操作.所以把这整个逻辑放在AsyncTask中. 

代码如下:

private class DownlaodUpdateTask extends        AsyncTask<RequestFileInfo, ProgressValue, BasicCallResult> {    @Override    protected BasicCallResult doInBackground(RequestFileInfo... params) {        final RequestFileInfo req = params[0];        String apkFileName = "";        try {            URL url = new URL(req.fileUrl); // throw MalformedURLException            HttpURLConnection conn = (HttpURLConnection) url                    .openConnection();// throws IOException            Log.i(TAG, "response code:" + conn.getResponseCode());            // 1检查网络连接性            if (HttpURLConnection.HTTP_OK != conn.getResponseCode()) {                return new BasicCallResult(                        "Can not connect to the update Server! ", false);            }            int length = conn.getContentLength();            double total = StringUtils.bytes2M(length);            InputStream is = conn.getInputStream();            File path = new File(req.saveFilePath);            if (!path.exists())                path.mkdir();            File apkFile = new File(req.saveFilePath, req.saveFileName);            apkFileName = apkFile.getAbsolutePath();            FileOutputStream fos = new FileOutputStream(apkFile);            ProgressValue progressValue = new ProgressValue(0, " downlaod…");            int count = 0;            long startTime, endTime;            byte buffer[] = new byte[1024];            do {                startTime = System.currentTimeMillis();                int numread = is.read(buffer);                endTime = System.currentTimeMillis();                count += numread;                if (numread <= 0) {                    // publish end                    break;                }                fos.write(buffer, 0, numread);                double kbPerSecond = Math                        .ceil((endTime - startTime) / 1000f);                double current = StringUtils.bytes2M(count);                progressValue.message = String.format(                        "%.2f M/%.2f M\t\t%.2fKb/S", total, current,                        kbPerSecond);                progressValue.progress = (int) (((float) count / length) * DialogUtil.LONG_PROGRESS_MAX);                publishProgress(progressValue);            } while (true);            fos.flush();            fos.close();        } catch (MalformedURLException e) {            e.printStackTrace();            return new BasicCallResult("Wrong url! ", false);        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();            return new BasicCallResult("Error: " + e.getLocalizedMessage(),                    false);        }        BasicCallResult callResult = new BasicCallResult(                "download finish!", true);        callResult.result = apkFileName;        return callResult;    }     @Override    protected void onPostExecute(BasicCallResult result) {        removeFragmentDialog();        if (result.ok) {            installApk(result.result);        } else {            ToastUtils.showFailure(getApplicationContext(), result.message);        }    }     @Override    protected void onProgressUpdate(ProgressValue... values) {        ProgressValue value = values[0];        updateProgressDialog(value);     } } /** * 安装更新APK. * * @param fileUri */private void installApk(String fileUri) {    Intent intent = new Intent(Intent.ACTION_VIEW);    intent.setDataAndType(Uri.parse("file://" + fileUri),            "application/vnd.android.package-archive");    startActivity(intent);    this.finish();}

PS:Java中传递或者返回多个值,我常用的办法就是将数据封装到一个对象中去.上面用到的一些封装对象如下:

传递多个值用对象是因为AsyncTask设计让你传递一个对象作为传递参数,所以传递对象也需要这样使用.

/** * 传递给android 设置进度条对象 * */public final class ProgressValue {    /**     * 需要设置的进度     */    public int progress;    /**     * 提示信息     */    public String message;    public ProgressValue(int progress, String message) {        super();        this.progress = progress;        this.message = message;    }}

基本的调用返回对象:

public class BasicCallResult {    public String message;    public boolean ok;    public String result;    public BasicCallResult(String message, boolean ok) {        super();        this.message = message;        this.ok = ok;    }}

传递下载相关信息..

public class RequestFileInfo {    public String fileUrl;    public String saveFilePath;    public String saveFileName;}