为什么不调用 doOnDispose? [英] Why is doOnDispose not called?

问题描述

当像这样创建一个 Observable 时:

When creating an Observable like this:

public void foo() {

    Observable observable = Observable.fromCallable(() -> {
        bar();
        return "";
      })
      .doOnSubscribe(disposable -> System.out.println("onSubscribe"))
      .doOnDispose(() -> System.out.println("onDispose"));

    Disposable disposable = observable.subscribe();
    disposable.dispose();    
}

private void bar() {
    System.out.println("bar");
}

doOnSubcribe 被调用，doOnDispose 未被调用.

doOnSubcribe is called, doOnDispose is not called.

这是为什么?

推荐答案

您需要使用 doFinally() 运算符.

You need to use the doFinally() operator.

doOnDispose() 有一个非常狭窄的用例，其中 observable 被显式处理.在您的示例中，可观察对象通过 onComplete()自然地"终止.到您调用 dispose() 时，可观察对象已完成，并且什么也不会发生——处理已完成的可观察对象没有任何效果.

doOnDispose() has a very narrow use case, where the observable is explicitly disposed. In your example, the observable terminates "naturally" by onComplete(). By the time that you call dispose(), the observable is done, and nothing will happen -- disposing a completed observable has no effect.

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