FirebaseMessagingService默认情况下是在后台运行吗？

Question

FirebaseMessagingService在后​​台运行与IntentService的运作方式类似吗？

我看到FirebaseMessagingService范围Service不在后台运行，但我想确定我是否应该在FirebaseMessagingService内异步进行任何工作或同步。

谢谢

Answer 1

if (choice == 1) { switch (from) { case 0: { if (to == 1) std::cout << " by foot "; if (to == 2) std::cout << " by foot -> by bus "; if (to == 3) std::cout << " by air "; break; } case 1: { if (to == 0) std::cout << " by foot "; if (to == 2) std::cout << " by bus "; if (to == 3) std::cout << " by bus -> by car "; break; } case 2: { if (to == 0) std::cout << " by bus -> by foot "; if (to == 1) std::cout << " by bus "; if (to == 3) std::cout << " by car "; break; } case 3: { if (to == 1) std::cout << " by car -> by bus "; if (to == 2) std::cout << " by car "; if (to == 0) std::cout << " by air "; } } 的方法FirebaseMessagingService在后​​台调用＆＃34;＆＃34; （不在UI /主线程上）。如果您尝试在onMessageReceived(RemoteMessage message)内进行异步工作，则会收到错误消息：

  

必须从主线程调用方法execute，当前推断的线程是worker。

所以在onMessageReceived(RemoteMessage message)内完成的所有工作都应该同步进行，因为它在自己的后台工作线程中。

Answer 2

Service没有＆＃34;在后台运行＆＃34;。 Service只是一个类的实例（即：一个对象）。 Service的方法可以在主（UI）线程或后台（工作线程）线程上运行。这一切都取决于他们的召唤方式。

服务onCreate()，onStartCommand()，onDestroy()的生命周期方法都在主（UI）线程上调用。但是在你的Service中，你可以启动其他线程并在这些线程上做其他事情。