Rxjava 简明教程
RxJava - BehaviorSubject
BehaviorSubject 向每个订阅的观察者发出它已观察到的最新项，然后发出所有后续观察到的项。
Class Declaration
以下是对 io.reactivex.subjects.BehaviorSubject<T> 类的声明：
public final class BehaviorSubject<T>
extends Subject<T>BehaviorSubject Example
在任意编辑器中使用任何您选择的语言（如 C:\>RxJava) 创建以下 Java 程序。
ObservableTester.java
import io.reactivex.subjects.BehaviorSubject;
public class ObservableTester {
public static void main(String[] args) {
final StringBuilder result1 = new StringBuilder();
final StringBuilder result2 = new StringBuilder();
BehaviorSubject<String> subject = BehaviorSubject.create();
subject.subscribe(value -> result1.append(value) );
subject.onNext("a");
subject.onNext("b");
subject.onNext("c");
subject.subscribe(value -> result2.append(value));
subject.onNext("d");
subject.onComplete();
//Output will be abcd
System.out.println(result1);
//Output will be cd being BehaviorSubject
//(c is last item emitted before subscribe)
System.out.println(result2);
}
}