这是一种可能的解决方案：
class TickHandler { private AtomicLong lastTick = new AtomicLong(0L); private Subscription subscription; void resume() { System.out.println("resumed"); subscription = Observable.interval(5, TimeUnit.SECONDS, Schedulers.io()).map(tick -> lastTick.getAndIncrement()).subscribe(tick -> System.out.println("tick = " + tick)); } void stop() { if (subscription != null && !subscription.isUnsubscribed()) { System.out.println("stopped"); subscription.unsubscribe(); } }}
