我的主要 Activity 有 2 个 AsyncTask，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) {
}
}
}
这是我想要完成的 AsyncTask。
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();
}
}
HttpPost pContador 和 HttpClient httpclientContador 是在主 Activity 中定义的变量。
当我尝试执行此代码时，应用程序总是崩溃，我想知道如何中止第二个 AsyncTask 中的 AsyncTask。
这是日志。
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)
最佳答案
您的问题是您正在尝试在 doInBackground 方法中打印 Toast。 该方法在后台线程中执行，因此无法与 UI 交互。 您可以在此处阅读更多相关内容。
您可以使用onPostExecute(Result)任务结束后通知用户的方法，或 onProgressUpdate(Progress...)在任务运行时更新。
关于java - 如何从另一个 AsyncTask 停止(中止)一个 AsyncTask？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22939209/