RxJava 操作符 take

Observable.interval(1, TimeUnit.SECONDS)
                  .take(10)
                  .subscribeOn(Schedulers.io())
                  .observeOn(AndroidSchedulers.mainThread())
                  .subscribe(new Subscriber() {
                    @Override public void onCompleted() {
                    }

                    @Override public void onError(Throwable e) {
                    }

                    @Override public void onNext(Long aLong) {
                    }
                  });

take操作符和interval操作符联合使用，由于一旦interval计时开始除了解绑就无法停止，所以只有在onNext方法中计算一旦释放到10秒的时候再进行解绑从而终结该计时。但使用take操作符就简单很多了，它的意思是只释放前N项，和计时配合使用的话，就可以不用担心计时会一直执行，10秒过后它会自动结束。

/**
     * Returns an Observable that emits only the first {@code num} items emitted by the source Observable.
     *
     *
     *
     * This method returns an Observable that will invoke a subscribing {@link Observer}'s
     * {@link Observer#onNext onNext} function a maximum of {@code num} times before invoking
     * {@link Observer#onCompleted onCompleted}.
     *
     *  Scheduler:
     *  This version of {@code take} does not operate by default on a particular {@link Scheduler}.
     *
     *
     * @param num
     *            the maximum number of items to emit
     * @return an Observable that emits only the first {@code num} items emitted by the source Observable, or
     *         all of the items from the source Observable if that Observable emits fewer than {@code num} items
     * @see ReactiveX operators documentation: Take
     */
    public final Observable take(final int num) {
        return lift(new OperatorTake(num));
    }