RxJava 操作符 concat

Concat操作符

public void test() {    Observable.concat(Observable.just("a"), Observable.just("b"), Observable.just("c")).subscribe(        new Observer<String>() {          @Override public void onCompleted() {            Log.e("test---onCompleted ", "onCompleted");          }          @Override public void onError(Throwable e) {          }          @Override public void onNext(String s) {            Log.e("test---onNext ", "onNext s : " + s);          }        });  }

04-22 16:44:43.822  28030-28030/com.fernandocejas.android10.sample.presentation E/test---onNext﹕ onNext s : a04-22 16:44:43.822  28030-28030/com.fernandocejas.android10.sample.presentation E/test---onNext﹕ onNext s : b04-22 16:44:43.822  28030-28030/com.fernandocejas.android10.sample.presentation E/test---onNext﹕ onNext s : c04-22 16:44:43.822  28030-28030/com.fernandocejas.android10.sample.presentation E/test---onCompleted﹕ onCompleted

可以将该操作符看作，依次将多个数据源释放到同一个地方。

/**     * Returns an Observable that emits the items emitted by three Observables, one after the other, without     * interleaving them.     * <p>     * <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/concat.png" alt="">     * <dl>     *  <dt><b>Scheduler:</b></dt>     *  <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>     * </dl>     *     * @param t1     *            an Observable to be concatenated     * @param t2     *            an Observable to be concatenated     * @param t3     *            an Observable to be concatenated     * @return an Observable that emits items emitted by the three source Observables, one after the other,     *         without interleaving them     * @see <a href="https://github.com/ReactiveX/RxJava/wiki/Mathematical-and-Aggregate-Operators#concat">RxJava wiki: concat</a>     */    public final static <T> Observable<T> concat(Observable<? extends T> t1, Observable<? extends T> t2, Observable<? extends T> t3) {        return concat(just(t1, t2, t3));    }