Question

在Android中，哪个线程可运行传递给ScheduledExecutorService#schedule(Runnable command, long delay, TimeUnit unit)从Executors#newSingleThreadScheduledExecutor()返回的运行？

至于我的努力，我运行这段代码：

        final ScheduledExecutorService ses = Executors.newSingleThreadScheduledExecutor();
        ses.schedule(new Runnable() {
            @Override
            public void run() {
                inflate.setBackgroundDrawable(background);
            }
        }, 200, TimeUnit.MILLISECONDS);
        ses.shutdown();

on Moto G 2013，Android 5.0.2和setBackgroundDrawable操作正常，意味着它在主（UI）线程上运行。

具体来说，这适用于所有Android版本和设备吗？链接的javadoc页面没有说明它。我想避免陷阱，服务可能会产生一个新的单线程来运行操作。

Answer 1

调用Thread时，将创建新的ThreadGroup（同一Executors.newSingleThreadScheduledExecutor()）。隐式使用的DefaultThreadFactory看起来像

static class DefaultThreadFactory implements ThreadFactory {
   private static final AtomicInteger poolNumber = new AtomicInteger(1);
   private final ThreadGroup group;
   private final AtomicInteger threadNumber = new AtomicInteger(1);
   private final String namePrefix;

   DefaultThreadFactory() {
       SecurityManager s = System.getSecurityManager();
       group = (s != null)? s.getThreadGroup() :
                            Thread.currentThread().getThreadGroup();
       namePrefix = "pool-" +
                     poolNumber.getAndIncrement() +
                    "-thread-";
   }

   public Thread newThread(Runnable r) {
       Thread t = new Thread(group, r,
                             namePrefix + threadNumber.getAndIncrement(),
                             0);
       if (t.isDaemon())
           t.setDaemon(false);
       if (t.getPriority() != Thread.NORM_PRIORITY)
           t.setPriority(Thread.NORM_PRIORITY);
       return t;
   }
}

如果你想重用UI-Thread，你应该编写自己的ThreadFactory返回UI-Thread并调用Executors.newSingleThreadScheduledExecutor(yourNewlyCreatedThreadFactory)

在Android中，哪些线程可运行传递给运行的Executors.newSingleThreadScheduledExecutor？

1 个答案: