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当我尝试通过ScheduledExecutorService使用发送任何操作时LocalBroadcastManager，似乎尚未发送实际操作（或尚未交付）。这是代码示例：

public class SomeService extends IntentService {
    private static final String TAG = SomeService.class.getSimpleName();
    public static final String ACTION = "some-action";

    private ScheduledExecutorService scheduledTaskExecutor = Executors.newScheduledThreadPool(1);

    public SomeService() {
        super(TAG);
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        String action = intent.getAction();
        if (action.equals("scheduled_action")) {
            scheduledTaskExecutor.schedule(new ScheduledAction(ACTION), 10, SECONDS);
        } else if (action.equals("send_it_now")) {
            sendAction(ACTION);
        }
    }

    private void sendAction(String action) {
        Log.d(TAG, "send action [" + action + "]");
        Intent intent = new Intent(action);
        LocalBroadcastManager.getInstance(SomeService.this).sendBroadcast(intent);
    }

    // it also could be Callable, but effect is pretty the same
    private class ScheduledAction implements Runnable {
        final String action;

        ScheduledAction(String action) {
            this.action = action;
        }

        @Override
        public void run() {
            sendAction(action);
        }
    }
}

根据传入的操作，服务ACTION会立即发送或在 10 秒后发送。这是订阅的活动ACTION：

public class SomeActivity extends Activity {
    private static final String TAG = SomeActivity.class.getName();
    private BroadcastReceiver actionReceiver = new ActionReceiver();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        IntentFilter filter = new IntentFilter();
        filter.addAction(SomeService.ACTION);
        LocalBroadcastManager.getInstance(this).registerReceiver(actionReceiver, filter);
    }

    @Override
    protected void onDestroy() {
        LocalBroadcastManager.getInstance(this).unregisterReceiver(actionReceiver);
        super.onDestroy();
    }

    private class ActionReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            Log.d(TAG, "received action [" + action + "]");
        }
    }
}

如果send_it_now一切都按预期工作：

Intent intent = new Intent(..., SomeService.class);
intent.setAction("send_it_now");
startService(intent);

我看到打印到 logcat 的适当消息：

...
SomeService send action [some-action]
SomeActivity received action [some-action] 
...

但是当我尝试使用时scheduled_action：

Intent intent = new Intent(..., SomeService.class);
intent.setAction("scheduled_action");
startService(intent);

我看到动作已发送，但未在活动中收到：

...
SomeService send action [some-action]
...

那么，任何人都可以解释这段代码有什么问题，或者至少说明我可以找到解释的方向吗？

一些更新。如果我将Timer和TimerTask用于相同的目的，我会使用ScheduledExecutorService和ScheduledFuture - 它可以工作！

4

1 回答 1

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由于您不在 UI 线程上，请尝试以下操作：

public void run() { Looper.prepare(); sendAction(action); Looper.loop(); } 

public void run()
{
    new AsyncTask<Void, Void, Void>()
    {
        @Override
        protected Void doInBackground(Void... params)
        {
            return null;
        }

        protected void onPostExecute(Void result)
        {
            sendAction(action);
        }
    }.execute();
}
于 2013-06-26T08:35:42.543 回答