Rxjava学习笔记（三）

变换操作符号

需求是：当我们的操作是当注册成功后去登录的连贯过程

Map操作符

Map操作是用来转换结果的方式

Observable.create(new ObservableOnSubscribe<Integer>(){
            @Override
            public void subscribe(ObservableEmitter<Integer> e) throws Exception {

                Log.d(TAG,"emitt:" + Thread.currentThread().getName());
                e.onNext(1);
            }
        }).subscribeOn(Schedulers.io())
                .map(new Function<Integer, String>() {
                    @Override
                    public String apply(Integer integer) throws Exception {
                        Log.d(TAG,"map:"+Thread.currentThread().getName());
                        return "This is "+ integer;
                    }
                })
                .observeOn(Schedulers.newThread())
                .subscribe(new Consumer<String>() {
                    @Override
                    public void accept(String s) throws Exception {
                        Log.d(TAG,"consumer:"+Thread.currentThread().getName());
                    }
        });
//运行结果

03-15 15:29:44.750 6275-6343/com.example.uds.recyclerviewtest D/MAP: emitt:RxCachedThreadScheduler-1
03-15 15:29:44.750 6275-6343/com.example.uds.recyclerviewtest D/MAP: map:RxCachedThreadScheduler-1
03-15 15:29:44.752 6275-6344/com.example.uds.recyclerviewtest D/MAP: consumer:RxNewThreadScheduler-1

注意顺序

      Observable.create(new ObservableOnSubscribe<Integer>(){
            @Override
            public void subscribe(ObservableEmitter<Integer> e) throws Exception {

                Log.d(TAG,"emitt:" + Thread.currentThread().getName());
                e.onNext(1);
            }
        }).subscribeOn(Schedulers.io())
                .observeOn(Schedulers.newThread())
                .map(new Function<Integer, String>() {
                    @Override
                    public String apply(Integer integer) throws Exception {
                        Log.d(TAG,"map:"+Thread.currentThread().getName());
                        return "This is "+ integer;
                    }
                })
                .subscribe(new Consumer<String>() {
                    @Override
                    public void accept(String s) throws Exception {
                        Log.d(TAG,"consumer:"+Thread.currentThread().getName());
                    }
        });


//运行结果

03-15 15:31:36.752 7944-8043/com.example.uds.recyclerviewtest D/MAP: emitt:RxCachedThreadScheduler-1
03-15 15:31:36.758 7944-8044/com.example.uds.recyclerviewtest D/MAP: map:RxNewThreadScheduler-1
03-15 15:31:36.758 7944-8044/com.example.uds.recyclerviewtest D/MAP: consumer:RxNewThreadScheduler-1

调换了map的所处的位置

当map在subscribeOn的后面，map执行是在和上游线程一个线程中
当map在observeOn的后面，map执行是在和下有线程一个线程中

上述中的 Map 我们是将Integer 转换为了 String 类型的结果

FlatMap

FlatMap 将一个发送事件的上游 Observable 变换为多个发送事件的 Observables，然后将他们发射的事件合并后放进一个单独的Observable中

FlatMap 不保证事件的顺序

        Observable.create(new ObservableOnSubscribe<Integer>() {
            @Override
            public void subscribe(ObservableEmitter<Integer> e) throws Exception {
                e.onNext(1);
                e.onNext(2);
                e.onNext(3);
            }
        }).flatMap(new Function<Integer, ObservableSource<String>>() {

            @Override
            public ObservableSource<String> apply(Integer integer) throws Exception {
                final List<String> list = new ArrayList<String>();
                for(int i=0;i<3;i++){
                    list.add("I am value "+integer);
                }
                return Observable.fromIterable(list).delay(100, TimeUnit.MILLISECONDS);
            }
        }).subscribe(new Consumer<String>() {
            @Override
            public void accept(String s) throws Exception {
                Log.d(TAG,s);
            }
        });


//运行结果

03-19 13:25:47.040 4531-4597/com.example.uds.recyclerviewtest D/MAP: I am value 1
03-19 13:25:47.040 4531-4597/com.example.uds.recyclerviewtest D/MAP: I am value 1
03-19 13:25:47.041 4531-4598/com.example.uds.recyclerviewtest D/MAP: I am value 2
03-19 13:25:47.041 4531-4598/com.example.uds.recyclerviewtest D/MAP: I am value 2
03-19 13:25:47.041 4531-4598/com.example.uds.recyclerviewtest D/MAP: I am value 2
03-19 13:25:47.042 4531-4597/com.example.uds.recyclerviewtest D/MAP: I am value 1
03-19 13:25:47.043 4531-4597/com.example.uds.recyclerviewtest D/MAP: I am value 3
03-19 13:25:47.043 4531-4597/com.example.uds.recyclerviewtest D/MAP: I am value 3
03-19 13:25:47.043 4531-4597/com.example.uds.recyclerviewtest D/MAP: I am value 3

Observable.fromIterable(list) 会将list中的每一个item都经过onNext发送出去

concatMap

concatMap 的效果和 flatMap的效果几乎是一样的，不过 concatMap 是严格按照顺序执行的

注册后登陆的代码示例

public interface API {

    @POST("product/detail.do")
    @FormUrlEncoded
    Observable<Product> getDetails(@Field("productId") Integer productId);


    @POST("user/login.do")
    @FormUrlEncoded
    Observable<ResponseBody> login(@Field("username") String username,@Field("password") String password);

    @POST("product/upload.do")
    @Multipart
    Observable<ResponseBody> uploadFile(@Part MultipartBody.Part upload_file);


}


        final HttpUrl loginUrl = HttpUrl.parse("http://192.168.125.120:8080/manage/user/login.do");
        OkHttpClient client = new OkHttpClient.Builder()
                .cookieJar(new CookieJar() {
                    private final HashMap<HttpUrl,List<Cookie>> cookieStore = new HashMap<HttpUrl, List<Cookie>>();
                    @Override
                    public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
                        cookieStore.put(url,cookies);
                    }

                    @Override
                    public List<Cookie> loadForRequest(HttpUrl url) {
                        List<Cookie> cookieList = cookieStore.get(loginUrl);
                       return cookieList != null ? cookieList : new ArrayList<Cookie>();
                    }
                }).build();

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("http://192.168.125.120:8080/manage/")
                .client(client)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .build();

        final API api = retrofit.create(API.class);

        api.login("admin","admin")
                .subscribeOn(Schedulers.io())//io线程中处理请求
                .observeOn(AndroidSchedulers.mainThread())//主线程中处理结果
                .doOnNext(new Consumer<ResponseBody>() {
                    @Override
                    public void accept(ResponseBody responseBody) throws Exception {
                        //可以在主线程根据相应结果做一些处理

                        //比如登陆成功 或者失败怎么处理 
                    }
                })
                .observeOn(Schedulers.io())//切换到io线程中发起查询数据的网络请求
                .flatMap(new Function<ResponseBody, ObservableSource<Product>>() {
                    @Override
                    public ObservableSource<Product> apply(ResponseBody responseBody) throws Exception {

                        return api.getDetails(26);
                    }
                }).observeOn(AndroidSchedulers.mainThread())//回到主线程中处理结果
                .subscribe(new Consumer<Product>() {
                    @Override
                    public void accept(Product product) throws Exception {
                        Log.d(TAG,product.toString());
                    }
                });