rxjavaandroid如何使用Zip操作符
对于我的android项目,我在理解RxJava中的zip操作符时遇到了很多困难。 问题 我需要能够发送一个网络请求上传视频 然后我需要发送一个网络请求来上传一张照片 最后,我需要添加一个描述,并使用前两个请求的响应将视频和图片的位置URL与描述一起上传到我的服务器 我认为zip操作符非常适合这个任务,因为据我所知,我们可以获取两个可观察对象(视频和图片请求)的响应,并将它们用于我的最终任务。 但我似乎无法按照我的设想实现这一点 我正在寻找一个人来回答如何做到这一点,可以在概念上与psuedo代码位。rxjavaandroid如何使用Zip操作符,java,android,rx-java,Java,Android,Rx Java,对于我的android项目,我在理解RxJava中的zip操作符时遇到了很多困难。 问题 我需要能够发送一个网络请求上传视频 然后我需要发送一个网络请求来上传一张照片 最后,我需要添加一个描述,并使用前两个请求的响应将视频和图片的位置URL与描述一起上传到我的服务器 我认为zip操作符非常适合这个任务,因为据我所知,我们可以获取两个可观察对象(视频和图片请求)的响应,并将它们用于我的最终任务。 但我似乎无法按照我的设想实现这一点 我正在寻找一个人来回答如何做到这一点,可以在概念上与psuedo代
谢谢
zip
运算符允许您从两个不同的可观察结果合成结果
// assuming each observable returns response in the form of String
Observable<String> movOb = Observable.create(...);
// if you use Retrofit
Observable<String> picOb = RetrofitApiManager.getService().uploadPic(...),
Observable.zip(movOb, picOb, new Func2<String, String, MyResult>() {
@Override
public MyResult call(String movieUploadResponse, String picUploadResponse) {
// analyze both responses, upload them to another server
// and return this method with a MyResult type
return myResult;
}
}
)
// continue chaining this observable with subscriber
// or use it for something else
您必须给出am lambda,该lambda将根据每个可观察对象发出的数据创建一个结果
Observable<MovieResponse> movies = ...
Observable<PictureResponse> picture = ...
Observable<Response> response = movies.zipWith(picture, (movie, pic) -> {
return new Response("description", movie.getName(), pic.getUrl());
});
可观察电影=。。。
可观察图片=。。。
可观察的反应=电影。zipWith(图片,(电影,图片)->{
返回新的响应(“description”,movie.getName(),pic.getUrl());
});
Zip操作符严格地对来自可观察对象的发射项进行配对。它等待两个(或多个)项目到达,然后合并它们。因此,是的,这将适合您的需要
我将使用Func2
链接前两个观测值的结果。
注意,如果您使用改型,这种方法会更简单,因为它的api接口可能会返回一个可观察的结果。否则,您需要创建自己的可观察对象
// assuming each observable returns response in the form of String
Observable<String> movOb = Observable.create(...);
// if you use Retrofit
Observable<String> picOb = RetrofitApiManager.getService().uploadPic(...),
Observable.zip(movOb, picOb, new Func2<String, String, MyResult>() {
@Override
public MyResult call(String movieUploadResponse, String picUploadResponse) {
// analyze both responses, upload them to another server
// and return this method with a MyResult type
return myResult;
}
}
)
// continue chaining this observable with subscriber
// or use it for something else
//假设每个可观察对象以字符串形式返回响应
可观察的movOb=可观察的。创建(…);
//如果你使用改装
Observable picOb=ReformationApiManager.getService().uploadPic(…),
zip(movOb、picOb、newfunc2(){
@凌驾
公共MyResult调用(String movieUploadResponse、String picUploadResponse){
//分析两个响应,将它们上载到另一台服务器
//并使用MyResult类型返回此方法
返回我的结果;
}
}
)
//继续将此可观察对象链接到订阅服务器
//或者用它来做别的事情
这里我举了一个例子,我是以异步方式使用Zip的,以防万一
/**
* Since every observable into the zip is created to subscribeOn a diferent thread, it´s means all of them will run in parallel.
* By default Rx is not async, only if you explicitly use subscribeOn.
*/
@Test
public void testAsyncZip() {
scheduler = Schedulers.newThread();
scheduler1 = Schedulers.newThread();
scheduler2 = Schedulers.newThread();
long start = System.currentTimeMillis();
Observable.zip(obAsyncString(), obAsyncString1(), obAsyncString2(), (s, s2, s3) -> s.concat(s2)
.concat(s3))
.subscribe(result -> showResult("Async in:", start, result));
}
/**
* In this example the the three observables will be emitted sequentially and the three items will be passed to the pipeline
*/
@Test
public void testZip() {
long start = System.currentTimeMillis();
Observable.zip(obString(), obString1(), obString2(), (s, s2, s3) -> s.concat(s2)
.concat(s3))
.subscribe(result -> showResult("Sync in:", start, result));
}
public void showResult(String transactionType, long start, String result) {
System.out.println(result + " " +
transactionType + String.valueOf(System.currentTimeMillis() - start));
}
public Observable<String> obString() {
return Observable.just("")
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> "Hello");
}
public Observable<String> obString1() {
return Observable.just("")
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> " World");
}
public Observable<String> obString2() {
return Observable.just("")
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> "!");
}
public Observable<String> obAsyncString() {
return Observable.just("")
.observeOn(scheduler)
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> "Hello");
}
public Observable<String> obAsyncString1() {
return Observable.just("")
.observeOn(scheduler1)
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> " World");
}
public Observable<String> obAsyncString2() {
return Observable.just("")
.observeOn(scheduler2)
.doOnNext(val -> {
System.out.println("Thread " + Thread.currentThread()
.getName());
})
.map(val -> "!");
}
/**
*由于zip中的每个可观察对象都是在不同的线程上创建的,这意味着它们都将并行运行。
*默认情况下,只有在显式使用subscribeOn时,Rx才是异步的。
*/
@试验
public-void-testAsyncZip(){
scheduler=Schedulers.newThread();
scheduler1=Schedulers.newThread();
scheduler2=Schedulers.newThread();
长启动=System.currentTimeMillis();
obaservable.zip(obAsyncString(),obAsyncString1(),obAsyncString2(),(s,s2,s3)->s.concat(s2)
康卡特先生(s3))
.subscribe(结果->显示结果(“异步输入:”,开始,结果));
}
/**
*在本例中,三个观测值将依次发射,三个项目将传递到管道
*/
@试验
公共void testZip(){
长启动=System.currentTimeMillis();
Observable.zip(obString(),obString1(),obString2(),(s,s2,s3)->s.concat(s2)
康卡特先生(s3))
.subscribe(结果->显示结果(“同步到:”,开始,结果));
}
公共void showResult(字符串事务类型、长起始、字符串结果){
System.out.println(结果+“”+
transactionType+String.valueOf(System.currentTimeMillis()-start));
}
公共可观测obString(){
返回可观察。仅(“”)
.doOnNext(val->{
System.out.println(“Thread”+Thread.currentThread()
.getName());
})
.map(val->“你好”);
}
公共可观测obString1(){
返回可观察。仅(“”)
.doOnNext(val->{
System.out.println(“Thread”+Thread.currentThread()
.getName());
})
.地图(val->“世界”);
}
公共可观测obString2(){
返回可观察。仅(“”)
.doOnNext(val->{
System.out.println(“Thread”+Thread.currentThread()
.getName());
})
.地图(val->“!”);
}
公共可观测的obAsyncString(){
返回可观察。仅(“”)
.observeOn(调度程序)
.doOnNext(val->{
System.out.println(“Thread”+Thread.currentThread()
.getName());
})
.map(val->“你好”);
}
公共可观测的obAsyncString1(){
返回可观察。仅(“”)
.observeOn(附表1)
.doOnNext(val->{
System.out.println(“Thread”+Thread.currentThread()
.getName());
})
.地图(val->“世界”);
}
公共可观测的obAsyncString2(){
返回可观察。仅(“”)
.observeOn(附表2)
.doOnNext(val->{
System.out.println(“Thread”+Thread.currentThread()
.getName());
})
.地图(val->“!”);
}
您可以在此处看到更多示例一个小示例:
val observableOne = Observable.just("Hello", "World")
val observableTwo = Observable.just("Bye", "Friends")
val zipper = BiFunction<String, String, String> { first, second -> "$first - $second" }
Observable.zip(observableOne, observableTwo, zipper)
.subscribe { println(it) }
在
BiFunction
中,第一个String
类型
@Test
public void zipOperator() throws Exception {
List<Integer> indexes = Arrays.asList(0, 1, 2, 3, 4);
List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
Observable<Integer> indexesObservable = Observable.fromIterable(indexes);
Observable<String> lettersObservable = Observable.fromIterable(letters);
Observable.zip(indexesObservable, lettersObservable, mergeEmittedItems())
.subscribe(printMergedItems());
}
@NonNull
private BiFunction<Integer, String, String> mergeEmittedItems() {
return new BiFunction<Integer, String, String>() {
@Override
public String apply(Integer index, String letter) throws Exception {
return "[" + index + "] " + letter;
}
};
}
@NonNull
private Consumer<String> printMergedItems() {
return new Consumer<String>() {
@Override
public void accept(String s) throws Exception {
System.out.println(s);
}
};
}
[0] a
[1] b
[2] c
[3] d
[4] e
//
// API Client Interface
//
@GET(ServicesConstants.API_PREFIX + "questions/{id}/")
Single<Response<ResponseGeneric<List<ResponseQuestion>>>> getBaseQuestions(@Path("id") int personId);
@GET(ServicesConstants.API_PREFIX + "physician/{id}/")
Single<Response<ResponseGeneric<List<ResponsePhysician>>>> getPhysicianInfo(@Path("id") int personId);
//
// API middle layer - NOTE: I had feedback that the Single.create is not needed (but I haven't yet spent the time to improve it)
//
public Single<List<ResponsePhysician>> getPhysicianInfo(int personId) {
return Single.create(subscriber -> {
apiClient.getPhysicianInfo(appId)
.subscribeOn(Schedulers.io())
.observeOn(Schedulers.io())
.subscribe(response -> {
ResponseGeneric<List<ResponsePhysician>> responseBody = response.body();
if(responseBody != null && responseBody.statusCode == 1) {
if (!subscriber.isDisposed()) subscriber.onSuccess(responseBody.data);
} else if(response.body() != null && response.body().status != null ){
if (!subscriber.isDisposed()) subscriber.onError(new Throwable(response.body().status));
} else {
if (!subscriber.isDisposed()) subscriber.onError(new Throwable(response.message()));
}
}, throwable -> {
throwable.printStackTrace();
if(!subscriber.isDisposed()) subscriber.onError(throwable);
});
});
}
public Single<List<ResponseQuestion>> getHealthQuestions(int personId){
return Single.create(subscriber -> {
apiClient.getBaseQuestions(personId)
.subscribeOn(Schedulers.io())
.observeOn(Schedulers.io())
.subscribe(response -> {
ResponseGeneric<List<ResponseQuestion>> responseBody = response.body();
if(responseBody != null && responseBody.data != null) {
if (!subscriber.isDisposed()) subscriber.onSuccess(response.body().data);
} else if(response.body() != null && response.body().status != null ){
if (!subscriber.isDisposed()) subscriber.onError(new Throwable(response.body().status));
} else {
if (!subscriber.isDisposed()) subscriber.onError(new Throwable(response.message()));
}
}, throwable -> {
throwable.printStackTrace();
if(!subscriber.isDisposed()) subscriber.onError(throwable);
});
});
}
//please note that ResponseGeneric is just an outer wrapper of the returned data - common to all API's in this project
public class ResponseGeneric<T> {
@SerializedName("Status")
public String status;
@SerializedName("StatusCode")
public float statusCode;
@SerializedName("Data")
public T data;
}
//
// API end-use layer - this gets close to the UI so notice the oberver is set for main thread
//
private static class MergedResponse{// this is just a POJO to store all the responses in one object
public List<ResponseQuestion> listQuestions;
public List<ResponsePhysician> listPhysicians;
public MergedResponse(List<ResponseQuestion> listQuestions, List<ResponsePhysician> listPhysicians){
this.listQuestions = listQuestions;
this.listPhysicians = listPhysicians;
}
}
// example of Single.zip() - calls getHealthQuestions() and getPhysicianInfo() from API Middle Layer
private void downloadHealthQuestions(int personId) {
addRxSubscription(Single
.zip(getHealthQuestions(personId), getPhysicianInfo(personId), MergedResponse::new)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(response -> {
if(response != null) {
Timber.i(" - total health questions downloaded %d", response.listQuestions.size());
Timber.i(" - physicians downloaded %d", response.listPhysicians.size());
if (response.listPhysicians != null && response.listPhysicians.size()>0) {
// do your stuff to process response data
}
if (response.listQuestions != null && response.listQuestions.size()>0) {
// do your stuff to process response data
}
} else {
// process error - show message
}
}, error -> {
// process error - show network error message
}));
}
Observable<MovieResponse> movies = ...
Observable<PictureResponse> picture = ...
Observable<ZipResponse> response = Observable.zip(movies, picture, ZipResponse::new);
class ZipResponse {
private MovieResponse movieResponse;
private PictureResponse pictureResponse;
ZipResponse(MovieResponse movieResponse, PictureResponse pictureResponse) {
this.movieResponse = movieResponse;
this.pictureResponse = pictureResponse;
}
public MovieResponse getMovieResponse() {
return movieResponse;
}
public void setMovieResponse(MovieResponse movieResponse) {
this.movieResponse= movieResponse;
}
public PictureResponse getPictureResponse() {
return pictureResponse;
}
public void setPictureResponse(PictureResponse pictureResponse) {
this.pictureResponse= pictureResponse;
}
}