RxJava使用from操作符之后怎么每次发射数据时延迟一段时间

Question

为了使用RxJava实现在ImageView中每隔指定时间加载一张系统图片的效果，

Observable.from(getUri()).timer(2,TimeUnit.SECONDS).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(uri

-> {

            Log.e("uri",uri+"");

            Glide.with(this).load(uri).into(img);}); 

            ｝

在getUri（）中返回了一个ArrayList<Uri>对象，然后每次发射一个uri到订阅者中，怎么让这个发射过程延迟调用。

使用timer操作符出现了以下错误：Unknown type class java.lang.Long. You must provide a Model of a type for which there is a registered ModelLoader, if you are using a custom model, you must first call Glide#register with a ModelLoaderFactory for your custom model class

Answer 1

你这个错误貌似你Glide引起的，和Timer没什么关系把！timer是延时发射函数，只执行一次。想要定时发送数据，试试interval函数：Observable.interval(2, TimeUnit.SECONDS)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .map(new Func1<Long, String>() {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; @Override&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; public String call(Long aLong) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return getUrl();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; })&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .subscribe(new Subscriber<String>() {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; @Override&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; public void onCompleted() {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; @Override&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; public void onError(Throwable e) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; @Override&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; public void onNext(String o) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Log.d("xxx interval with func", o);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; });

Answer 2

对于定时任务，必然是从interval开始，不要老想着从数据开始public void loop() {&nbsp; &nbsp; final List<String> images = getUri();//图片列表&nbsp; &nbsp; Observable.interval(0, 2, TimeUnit.SECONDS)//每2秒执行1次，第一次立即执行&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .map(i -> images.get(i.intValue() % images.size()))//把循环次数变成图片路径&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .subscribe(uri -> Glide.with(ctx).load(uri).into(img));//调用Glide&nbsp; &nbsp; }楼主的错误在于，timer是静态方法，前面的from(getUri())根本没起到作用，发送出来的不是图片地址，而是循环次数，类型是Long,丢给Glide后类型出错。