Java 如何从另一个异步任务停止（中止）一个异步任务？

我有一个包含2个AsyncTask的主活动，我希望其中一个

AsyncTask

中止另一个

AsyncTask

class Contador extends AsyncTask<String, String, String>{

@Override
protected void onPreExecute() {

    }

@Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
     try {
            httpclientContador = new DefaultHttpClient();

            String sContador = "http://webmilab.com/SEDESOL/index.php/transferencias/conteo/" + resIdEncuesta;

            pContador = new HttpPost(sContador);


            pContador.addHeader("content-type", "application/x-www-form-urlencoded");
            JSONObject jContador = new JSONObject();
            jContador.put("mensaje", "Empezar a contar :)");

            StringEntity eContador = new StringEntity("json="+jContador.toString(), "UTF-8");
            pContador.setEntity(eContador);
            httpclientContador.execute(pContador);


        } catch (IOException e) {
            e.printStackTrace();
            Toast.makeText(TransferirDatos.this, "Hubo un error al realizar la petición del conteo", Toast.LENGTH_LONG).show();

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


        return null;
    }

    protected void onPostExecute(String file_url) { 

        }

    }

}

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您的问题是，您试图在doInBackground方法中打印一个Toast。 此方法在后台线程中执行，因此无法与UI交互。 你可以在这里读到更多

---

您可以使用此方法在任务结束后通知用户，或在任务运行时使用此方法更新。

第二个类中的您的pContador在哪里？你能发布crashHttpPost pContador的日志吗？pContador是一个全局变量。你在全局范围内初始化了两个AsyncTask类吗？是的，我在全局范围内初始化了这两个类，当我按下i按钮时，它们都被初始化了。非常感谢，它在没有Toast的情况下工作了。还有一个问题，当我中止AsyncTask时，onpostExecute被执行？？否，onpostExecute作为参数获取onBackground的结果，因此如果onBackground没有被调用，onpostExecute永远不会被调用。您可以退房，但仍不会在所有情况下都打电话给您。

class Contador extends AsyncTask<String, String, String>{

    @Override
    protected void onPreExecute() {
    }

    @Override
    protected String doInBackground(String... params) {
        // TODO Auto-generated method stub

        //Some Code

        return null;
    }

    protected void onPostExecute(String file_url) { 

        pContador.abort();  

    }

}

04-08 09:22:48.625: E/AndroidRuntime(10950): FATAL EXCEPTION: AsyncTask #3
04-08 09:22:48.625: E/AndroidRuntime(10950): java.lang.RuntimeException: An error occured while executing doInBackground()
04-08 09:22:48.625: E/AndroidRuntime(10950):    at android.os.AsyncTask$3.done(AsyncTask.java:278)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at java.lang.Thread.run(Thread.java:856)
04-08 09:22:48.625: E/AndroidRuntime(10950): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
04-08 09:22:48.625: E/AndroidRuntime(10950):    at android.os.Handler.<init>(Handler.java:121)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at android.widget.Toast$TN.<init>(Toast.java:317)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at android.widget.Toast.<init>(Toast.java:91)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at android.widget.Toast.makeText(Toast.java:233)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at tsp.consulting.TransferirDatos$Contador.doInBackground(TransferirDatos.java:184)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at tsp.consulting.TransferirDatos$Contador.doInBackground(TransferirDatos.java:1)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at android.os.AsyncTask$2.call(AsyncTask.java:264)
04-08 09:22:48.625: E/AndroidRuntime(10950):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)