但是第一个Asynctask有效，按下按钮后第二个无效

Question

I have seen all the answers to the previous questions however, can't understand the code to my needs and a bit confused.

I am trying to run two AsyncTasks simultaneously which are place in two different classes when pressed button in my third class. I understand I need to used executeOnExecutor but what I can't understand where and what should be the contents to my needs of it. Do I use in both the classes when I'm implementing individually or in the third class where I'm executing when button is pressed.

Code of third class where I'm executing AsyncTask:

     new NewAppliance().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
     new NewChecksAndOperations().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);

In both class where these are implemented, I'm targeting HONEYCOMB too as:

@TargetApi(Build.VERSION_CODES.HONEYCOMB) 
@Override
public void onCreate(Bundle savedInstanceState) 
{

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if (android.os.Build.VERSION.SDK_INT > 11) 
    {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
    }

Answer 1

In fact, you are already doing it right.

executeOnExecutor () works on a specific AsyncTask instance, hence has to be called for each and every AsyncTask instance for which you want it to take effect.

That is, you can either call:

new MyAsyncTask(..).execute();  // <----  standard

For standard execution, or:

new MyAsyncTask(..).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);

For parallel execution.

As I'm sure you already know, default execute() behavior for Android >= 3.0 is sequential processing. Remeber to both instantiate and execute() (or executeOnExecutor()) your AsyncTasks from the UI thread,

Finally, and I understand this is not the subject of your questions, please make a habit of wrapping all of your StrictMode processing within a DEBUG test:

boolean isDebuggable = (0 != (getApplicationInfo().flags & ApplicationInfo.FLAG_DEBUGGABLE));

if (isDebuggable ) {
       set StrictMode here..
}

br> You do not want StrictMode tests running at your users...

EDIT

To test a fixed pool executor (instead of an AsyncTask) do as follows:

ExecutorService pool = Executors.newFixedThreadPool(2);

for (int i = 0; i < 2; i++) {
     pool.execute(new Runnable() {
           public void run() { 
               // do something with no UI access!
        }
      });
}