ObservableOnSubscribe(interface)
+ subscribe(@NonNull ObservableEmitter<T> emitter):void
HasUpstreamObservableSource
+ source():ObservableSource
实现抽象类
Observable
ObservalableCreate
+ source:ObservableOnSubscribe+subcribeActual(Observer o)+subcribe(Observer o)
ObservalableFlatMap
+subcribeActual(Observer o)+subcribe(Observer o)
实现该接口
ObservableSource(interface)
+ subscribe(@NonNull Observer<? super T> observer):void
继承
1.调用create方法生成该对象，传入一个ObservableOnSubscribe保存到对象成员变量source中
ObservalableMap
AbstractObservableWithUpstream
# source:ObservableSource(构造方法传入)
