按顺序执行2个observable并立即获得结果 - RxJava 2

时间:2017-02-28 12:54:31

标签: android rx-java rx-java2

我有这个功能:

public static class CombinedResult<T, R> {
    T t;
    R r;

    public CombinedResult(T t, R r) {
        this.t = t;
        this.r = r;
    }

    public T getObject1() {
        return t;
    }

    public void setObject1(T t) {
        this.t = t;
    }

    public R getObject2() {
        return r;
    }

    public void setObject2(R r) {
        this.r = r;
    }

}

public static <A, B> Observable<CombinedResult<A, B>> combineObservablesParallel(Observable<A>
    return Observable.zip(observable1, observable2, new BiFunction<A, B, CombinedResult<A, B>>() {
        @Override
        public CombinedResult<A, B> apply(A a, B b) throws Exception {
            return new CombinedResult<>(a,b);
        }
    });
}

它结合了 2 observable并返回 1 Observable,它将两个observable的结果都放到CombinedResult对象中,这里的问题是 { {1}} 函数组合了Paralllel上的observable。

我想要与zip相同的东西,它按顺序执行observable并返回zip或类似的结果。

可以解决什么问题?

1 个答案:

答案 0 :(得分:3)

使用flatMap上的observable1运算符与observable2zip运算符结合使用:

RxJava 1:

return observable1
                .flatMap(new Func1<A, Observable<CombinedResult<A, B>>>() {
                    @Override
                    public Observable<CombinedResult<A, B>> call(A a) {
                        return Observable.just(a).zipWith(observable2, new Func2<A, B, CombinedResult<A, B>>() {
                            @Override
                            public CombinedResult<A, B> call(A a, B b) {
                                return new CombinedResult<>(a, b);
                            }
                        });
                    }
                });

RxJava 2:

return observable1.flatMap(new Function<A, ObservableSource<CombinedResult<A,B>>>() {
    @Override
    public ObservableSource<CombinedResult<A,B>> apply(A a) throws Exception {
        return Observable.just(a).zipWith(observable2, new BiFunction<A, B, CombinedResult<A, B>>() {
            @Override
            public CombinedResult<A, B> apply(A a, B b) throws Exception {
                return new CombinedResult<>(a,b);
            }
        });
    }
});

RxJava 2 Lambda:

return observable1.flatMap(a -> Observable.just(a).zipWith(observable2, CombinedResult::new));