使用AsyncTask实现Android应用自动更新(转）

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.

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private void checkUpdate() {

02
 
03
    RequestFileInfo requestFileInfo = new RequestFileInfo();

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    requestFileInfo.fileUrl = "http://www.waitab.com/demo/demo.apk";

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    String status = Environment.getExternalStorageState();

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    if (!Environment.MEDIA_MOUNTED.equals(status)) {

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        ToastUtils.showFailure(getApplicationContext(),

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                "SDcard cannot use!");

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        return;

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    }

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    requestFileInfo.saveFilePath = Environment

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            .getExternalStoragePublicDirectory(

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                    Environment.DIRECTORY_DOWNLOADS).getAbsolutePath();

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    requestFileInfo.saveFileName = "DiTouchClient.apk";

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    showHorizontalFragmentDialog(R.string.title_wait,

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            R.string.title_download_update);

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    new DownlaodUpdateTask().execute(requestFileInfo);

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}

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:

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private class DownlaodUpdateTask extends

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        AsyncTask<RequestFileInfo, ProgressValue, BasicCallResult> {

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004
    @Override

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    protected BasicCallResult doInBackground(RequestFileInfo... params) {

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        final RequestFileInfo req = params[0];

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        String apkFileName = "";

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        try {

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            URL url = new URL(req.fileUrl); // throw MalformedURLException

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            HttpURLConnection conn = (HttpURLConnection) url

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                    .openConnection();// throws IOException

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            Log.i(TAG, "response code:" + conn.getResponseCode());

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            // 1检查网络连接性

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            if (HttpURLConnection.HTTP_OK != conn.getResponseCode()) {

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                return new BasicCallResult(

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                        "Can not connect to the update Server! ", false);

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            }

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            int length = conn.getContentLength();

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            double total = StringUtils.bytes2M(length);

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            InputStream is = conn.getInputStream();

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            File path = new File(req.saveFilePath);

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            if (!path.exists())

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                path.mkdir();

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            File apkFile = new File(req.saveFilePath, req.saveFileName);

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            apkFileName = apkFile.getAbsolutePath();

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            FileOutputStream fos = new FileOutputStream(apkFile);

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            ProgressValue progressValue = new ProgressValue(0, " downlaod…");

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            int count = 0;

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            long startTime, endTime;

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            byte buffer[] = new byte[1024];

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            do {

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                startTime = System.currentTimeMillis();

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                int numread = is.read(buffer);

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                endTime = System.currentTimeMillis();

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                count += numread;

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                if (numread <= 0) {

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                    // publish end

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                    break;

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                }

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                fos.write(buffer, 0, numread);

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                double kbPerSecond = Math

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                        .ceil((endTime - startTime) / 1000f);

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                double current = StringUtils.bytes2M(count);

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                progressValue.message = String.format(

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                        "%.2f M/%.2f M		%.2fKb/S", total, current,

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                        kbPerSecond);

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                progressValue.progress = (int) (((float) count / length) * DialogUtil.LONG_PROGRESS_MAX);

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                publishProgress(progressValue);

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            } while (true);

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            fos.flush();

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            fos.close();

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        } catch (MalformedURLException e) {

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            e.printStackTrace();

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            return new BasicCallResult("Wrong url! ", false);

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        } catch (IOException e) {

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            // TODO Auto-generated catch block

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            e.printStackTrace();

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            return new BasicCallResult("Error: " + e.getLocalizedMessage(),

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                    false);

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        }

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        BasicCallResult callResult = new BasicCallResult(

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                "download finish!", true);

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        callResult.result = apkFileName;

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        return callResult;

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    }

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070
    @Override

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    protected void onPostExecute(BasicCallResult result) {

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        removeFragmentDialog();

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        if (result.ok) {

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            installApk(result.result);

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        } else {

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            ToastUtils.showFailure(getApplicationContext(), result.message);

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        }

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    }

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    @Override

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    protected void onProgressUpdate(ProgressValue... values) {

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        ProgressValue value = values[0];

083
        updateProgressDialog(value);

084
 
085
    }

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087
}

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/**

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 * 安装更新APK.

091
 * 

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 * @param fileUri

093
 */

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private void installApk(String fileUri) {

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    Intent intent = new Intent(Intent.ACTION_VIEW);

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    intent.setDataAndType(Uri.parse("file://" + fileUri),

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            "application/vnd.android.package-archive");

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    startActivity(intent);

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    this.finish();

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}

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.

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/**

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 * 传递给android 设置进度条对象

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 * 

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 * <a href="http://my.oschina.net/arthor" class="referer" target="_blank">@author</a>  banxi1988

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 * 

06
 */

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public final class ProgressValue {

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    /**

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     * 需要设置的进度

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     */

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    public int progress;

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    /**

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     * 提示信息

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     */

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    public String message;

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    public ProgressValue(int progress, String message) {

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        super();

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        this.progress = progress;

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        this.message = message;

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    }

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}

基本的调用返回对象:

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public class BasicCallResult {

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    public String message;

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    public boolean ok;

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    public String result;

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    public BasicCallResult(String message, boolean ok) {

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        super();

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        this.message = message;

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        this.ok = ok;

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    }

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}

传递下载相关信息..

`1`	`public` `class` `RequestFileInfo {`

`2`	`public` `String fileUrl;`

`3`	`public` `String saveFilePath;`

`4`	`public` `String saveFileName;`

5

6 }