android - 如何在 doInBackground() 方法中定期检查 isCancelled()

Question

我想取消异步任务并停止其后台执行，我在这个问题中找到了解决方案，:

Android - Cancel AsyncTask Forcefully

但实际上，我在 asynctask 中的代码是将一些数据上传/发布到服务器，我不知道如何使用 while 或 for loop 和 根据上述问题的答案在此处打破语句

我的 AsyncTask 是:

private class Userdataupload extends AsyncTask<String, Void, String> {

    @Override
    protected String doInBackground(String[] params) {
        // do above Server call here


        HttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost("http://www.example.com/example.php");

        int mode = Activity.MODE_PRIVATE;
        SharedPreferences my2 = getSharedPreferences("data", mode);
        String u = my2.getString("name", "error");
        String v = my2.getString("coin", "error");


        List<NameValuePair> nameValuePair = new ArrayList<NameValuePair>(2);
        nameValuePair.add(new BasicNameValuePair("name", u));
        nameValuePair.add(new BasicNameValuePair("coin", v));

        try {
            httpPost.setEntity(new UrlEncodedFormEntity(nameValuePair));

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        try {
            HttpResponse response = httpClient.execute(httpPost);
            // write response to log
            //tdt(response.toString());
            Log.d("Http Post Response:", response.toString());
        } catch (ClientProtocolException e) {
            // Log exception
            e.printStackTrace();
        } catch (IOException e) {
            // Log exception
            e.printStackTrace();
        }

        return null;
    }

   @Override
   protected void onPreExecute()
   {
       pf = new ProgressDialog(MainActivity.this);
       pf.setMessage("Loading User Data...");
       pf.show();
       pf.setCanceledOnTouchOutside(false);
       pf.setCancelable(true);
   }


    @Override
    protected void onPostExecute(String message) {
        //process message
        pf.cancel();

    }
}

Answer 1

我想你会需要这个

在您的 doinbackground 方法中，在具有真值的 while 循环中运行您的代码 fragment 。

如果按下 iscancelled() 将其设置为 false 并且打破你的后台进程

方法是这样的

`int isExecxute=true;
 While(isExecute){
 //run your code
//cancelled break the loop and finish your           execution
 If (iscancelled()) isExecute=false;
  }`