如何修改主题输出类型？

Question

我有以下单例：

public abstract class Store<Input, Output> {
    private BehaviorSubject<Input> subject = BehaviorSubject.create();
    private Observable<Output> observable; //also a singleton

    public final Subscription register(Subscriber<Output> subscriber) {
        if (observable == null) {
            observable = subject.compose(getTransformer()); //is this hot?
        }
        return observable.subscribe(subscriber);
    }

    public final void unregister(Subscription subscription) { //unregister }

    //applies operators to the original stream to transform Input -> Output
    protected abstract Observable.Transformer<Input, Output> getTransformer();

    public final void onNext(Input event) { subject.onNext(event);}
}

问题： 当我旋转设备或最小化应用程序时，observable 死机（中止网络执行）。 subject.compose() 是否返回一个冷的可观察对象，如果是，为什么？

我尝试使用 publish.autoConnect() / share() 使其变热，现在它不会在旋转时死掉...但是 BehaviourSubject 会损坏。当我旋转设备时，我没有在订阅时获得第一个值。

我怎样才能转换 subject 的输出值并使其仍然像 subject 那样工作？ SAMPLE PROJECT

日志：

USER: hits button to fetch from network
D: Retrieving from
network... D: Network request executed successfully
D: Caching to memory
USER: hits button to fetch from network again
D: Retrieving from network...
USER: pressed home button, app backgrounded
D:.unsubscribe()

Answer 1

事实证明，我一直在使用错误的主题。这是我上面想要实现的正确版本：

 public abstract class RxStore<Input, Output> {
        private BehaviorRelay<Output> relay;

        public final Subscription register(Subscriber<Output> subscriber) {
            if (relay == null) {
                relay = BehaviorRelay.create(defaultValue());
            }
            return relay.subscribe(subscriber);
        }

        public final void unregister(Subscription subscription) {
            if (subscription != null && !subscription.isUnsubscribed()) {
                subscription.unsubscribe();
            }
        }

        public void execute(Input event) {
            buildObservable(event).subscribe(relay);
        }

        /**
         * @return the first or default value emitted to subscribers
         */
        protected Output defaultValue() {
            return null;
        }

        /**
         * @return an buildObservable responsible of handling its own errors.
         */
        protected abstract Observable<Output> buildObservable(Input event);
    }

编辑：

我发现这种方法非常有用。我在产品中使用这种方法，我写了一篇关于这个的文章：

https://medium.com/@FerRaviola/rxandroid-an-event-bus-on-steroids-9699e93eca98#.tqbxleo4h

如何修改主题输出类型？

How to modify subject output type?

android

rx-java

rx-android