學習 RxJava <三>flatMap

出於安全性、性能等方面的考慮，多數服務器會有一些接口須要傳入 token 才能正確返回結果，而 token 是須要從另外一個接口獲取的，這就須要使用兩步連續的請求才能獲取數據（①token -> ②目標數據）。

使用 flatMap() 能夠用較爲清晰的代碼實現這種連續請求，避免 Callback 嵌套的結構。代碼大體形式

api.getToken().flatMap(token -> api.getData(token)).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(observer);

 

這幾天作一個自動定位，根據獲取的經度 緯度，查詢api獲得地點名稱，再根據地點 查詢api獲得 天氣。 固然有api能夠直接經過經緯度查詢到天氣狀況，這裏選擇前者來模擬兩步請求的狀況 來使用flatMap

傳入的 s 爲 經緯度

call 方法中 打印出 天氣狀況和溫度

 1     private void getMobWeather(String s){
 2         stopLBS();
 3 
 4         LocationApi locationApi=Network.Loadlocation();
 5         final MobWeatherApi mobWeatherApi=Network.LoadMobWeather();
 6 
 7         locationApi.getLocation("cvucm4utiqosrdom",s).flatMap(new Func1<Location, Observable<MobWeather>>() {
 8             @Override
 9             public Observable<MobWeather> call(Location location) {
10                 List<Location.ResultsBean> results =location.getResults();
11                 String name=results.get(0).getName();
12                 Logger.e("HeWeather  "+name);
13                 return mobWeatherApi.getMobWeather("142fcfa226a92",name);
14             }
15         }).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(new Action1<MobWeather>() {
16             @Override
17             public void call(MobWeather mobWeather) {
18                 Logger.e("getMsg  "+mobWeather.getMsg()+"  Code  "+mobWeather.getRetCode());
19                 if ("200".equals(mobWeather.getRetCode())){
20                     List<MobWeather.ResultBean>resultBeen= mobWeather.getResult();
21                     String weather=resultBeen.get(0).getWeather();
22                     String temp=resultBeen.get(0).getTemperature();
23                     Logger.e("weather "+weather+"  temp  "+temp);
24                 }
25             }
26         }, new Action1<Throwable>() {
27             @Override
28             public void call(Throwable throwable) {
29                 Logger.e("throwable  "+throwable.getMessage());
30             }
31         });
32     }

 

Network中使用到的

 1     public static LocationApi Loadlocation(){
 2         if (locationApi==null){
 3             Retrofit retrofit=new Retrofit.Builder().baseUrl("https://api.thinkpage.cn/v3/").client(okHttpClient).addConverterFactory(gsonConverterFactory).addCallAdapterFactory(rxJavaCallAdapterFactory).build();
 4             locationApi=retrofit.create(LocationApi.class);
 5         }
 6         return locationApi;
 7     }
 8 
 9     public static MobWeatherApi LoadMobWeather(){
10         if (mobWeatherApi==null){
11             Retrofit retrofit=new Retrofit.Builder().baseUrl("http://apicloud.mob.com/").client(okHttpClient).addConverterFactory(gsonConverterFactory).addCallAdapterFactory(rxJavaCallAdapterFactory).build();
12             mobWeatherApi=retrofit.create(MobWeatherApi.class);
13         }
14         return mobWeatherApi;
15     }

 

LocationApi

1 public interface LocationApi {
2 
3     //https://api.thinkpage.cn/v3/location/search.json?key=cvucm4utiqosrdom&q=39.93:116.40
4 
5     @GET("location/search.json?")
6     rx.Observable<Location>getLocation(@Query("key") String key,
7                                        @Query("q")String q
8                                        );
9 }

 

MobWeatherApi

1 public interface MobWeatherApi {
2 
3     //http://apicloud.mob.com/v1/weather/query?key=142fcfa226a92&city=%E5%AE%BF%E6%9D%BE
4 
5     @GET("v1/weather/query?")
6     rx.Observable<MobWeather>getMobWeather(@Query("key") String key,
7                                            @Query("city")String city);
8 }

 

在找api的時候 先選擇的和風天氣返回來的json 格式有點問題，沒法直接用 gsonformat 生成javabean，解決方法在此，可是Network中的操做都是一鼓作氣，暫時不知道在哪對流進行處理