未收集 AsyncTask 导致其他 AsyncTask 无法运行

Here is an example of one of the AsyncTasks:

private class RunningEvent extends AsyncTask<Void, Void, Response> {

    @Override
    protected void onPreExecute() {
        if (Constants.isOnline(getApplicationContext())) {
            super.onPreExecute();
        } else {
            Toast.makeText(getApplicationContext(),
                    "No internet connection", Toast.LENGTH_LONG).show();
            return;
        }
    }

    @Override
    protected Response doInBackground(Void... empty) {
        HttpClient client = new DefaultHttpClient();
        HttpPost post = new HttpPost(URL);

        try {
            List<NameValuePair> values = new ArrayList<NameValuePair>(5);
            values.add(new BasicNameValuePair("tag", "eventRunning"));
            values.add(new BasicNameValuePair("userid", String
                    .valueOf(response.user.userid)));
            post.setEntity(new UrlEncodedFormEntity(values));

            HttpResponse httpresponse = client.execute(post);
            HttpEntity entity = httpresponse.getEntity();
            InputStream stream = entity.getContent();

            Log.i("MenuActivity",
                    "Input streamed, parsing Gson for existing events");
            Gson gson = new Gson();
            Reader reader = new InputStreamReader(stream);

            eventresponse = gson.fromJson(reader, Response.class);
            return eventresponse;
        } catch (Exception e) {
            e.printStackTrace();
            Log.e("RunningEvent", "Error sending data to Server");
        }
        return null;
    }

    @Override
    protected void onPostExecute(Response result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        Log.i("MenuActivity", "Binding button");
        if (eventresponse != null) {
            if (eventresponse.success == 1) {
                eventresponse.user = response.user;
                bActivity.setOnClickListener(new OnClickListener() {

                    public void onClick(View arg0) {
                        Intent i = new Intent("com.xxx.xxx.EVENT");
                        i.putExtra("response", eventresponse);
                        running = false;
                        switcher.cancel(true);
                        MenuActivity.this.finish();
                        startActivity(i);
                    }

                });
            } else {
                bActivity.setText("Nieuw activity");
                bActivity.setOnClickListener(new OnClickListener() {

                    public void onClick(View arg0) {
                        Intent i = new Intent("com.xxx.xxx.NEWEVENT");
                        i.putExtra("response", response);
                        running = false;
                        switcher.cancel(true);
                        MenuActivity.this.finish();
                        startActivity(i);
                    }

                });
            }
        } else {
            Log.i("RunningEvent", "Response is null");
        }
    }

}

上面的例子是有时作为第 6 个 AsyncTask 运行，它永远不会进入 doInBackground() 方法.我相信这是 SERIAL_EXECUTOR 的 5 个 Thread 限制.我通过将大多数 AsyncTasks 放在 THREAD_POOL_EXECUTOR 中解决"了这个问题，但这只是在避免它.

private static final int CORE_POOL_SIZE = 5;
private static final int MAXIMUM_POOL_SIZE = 128;
private static final int KEEP_ALIVE = 1;

... ...

/**
 * An {@link Executor} that can be used to execute tasks in parallel.
 */
public static final Executor THREAD_POOL_EXECUTOR
        = new ThreadPoolExecutor(CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE,
                TimeUnit.SECONDS, sPoolWorkQueue, sThreadFactory);

private static class SerialExecutor implements Executor {
    final ArrayDeque<Runnable> mTasks = new ArrayDeque<Runnable>();
    Runnable mActive;

    public synchronized void execute(final Runnable r) {
        mTasks.offer(new Runnable() {
            public void run() {
                try {
                    r.run();
                } finally {
                    scheduleNext();
                }
            }
        });
        if (mActive == null) {
            scheduleNext();
        }
    }

    protected synchronized void scheduleNext() {
        if ((mActive = mTasks.poll()) != null) {
            THREAD_POOL_EXECUTOR.execute(mActive);
        }
    }
}