一、最基本的使用格式：
用subscribeOn()和observerOn()来控制线程，并通过subscribe()来触发网络请求的开始。代码大致形式：
disposable = api.getData()
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(observer);
样例：
1、导入库Rxjava和Retrofit库：
//okHttp log拦截器
implementation 'com.squareup.okhttp3:logging-interceptor:3.4.1'
implementation 'com.squareup.retrofit2:retrofit:2.5.0'
implementation 'com.squareup.retrofit2:converter-gson:2.5.0'
implementation 'com.squareup.retrofit2:adapter-rxjava2:2.5.0'
implementation 'io.reactivex.rxjava2:rxjava:2.2.4'
implementation 'io.reactivex.rxjava2:rxandroid:2.1.0'
2、第二步：网络请求接口api转成接口interface
public interface ZhuangbiApi {
@GET("search")
Observable> search(@Query("q") String query);
}
3、第三步：api接口创建实现类
public class NetWork {
private static ZhuangbiApi zhuangbiApi;
private static Converter.Factory gsonConverterFactory = GsonConverterFactory.create();
private static CallAdapter.Factory rxJavaCallAdapterFactory = RxJava2CallAdapterFactory.create();
public static OkHttpClient getOkHttpClient() {
//新建log拦截器
HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor(new HttpLoggingInterceptor.Logger() {
@Override
public void log(String message) {
Log.d("zcb", "OkHttp====Message:" + message);
}
});
//日志显示级别
loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
//定制OkHttp
OkHttpClient.Builder httpClientBuilder = new OkHttpClient
.Builder();
//OkHttp进行添加拦截器loggingInterceptor
httpClientBuilder.addInterceptor(loggingInterceptor);
return httpClientBuilder.build();
}
public static ZhuangbiApi getZhuangbiApi() {
if (zhuangbiApi == null) {
Retrofit retrofit = new Retrofit.Builder()
.client(getOkHttpClient())
.baseUrl("http://www.zhuangbi.info/")
.addConverterFactory(gsonConverterFactory)
.addCallAdapterFactory(rxJavaCallAdapterFactory)
.build();
zhuangbiApi = retrofit.create(ZhuangbiApi.class);
}
return zhuangbiApi;
}
}
4、第四步使用
disposable = Network.getZhuangbiApi()
.search(key)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer>() {
@Override
public void accept(@NonNull List images) throws Exception {
swipeRefreshLayout.setRefreshing(false);
adapter.setImages(images);
}
}, new Consumer() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
swipeRefreshLayout.setRefreshing(false);
Toast.makeText(getActivity(), R.string.loading_failed, Toast.LENGTH_SHORT).show();
}
});
二、转换（map）：
有些服务端的接口设计，会在返回的数据外层包裹一些额外信息，这些信息对于调试很有用，但本地显示是用不到的。使用map()可以把外层的格式剥掉，只留下本地会用到的核心格式。（当然，map()也可以用于基于其他各种需求的格式转换）代码大致形式：
disposable = api.getData()
.map(response->response.data)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(observer);
使用案例：
需实现Function接口重写apply方法进行转换
public class GankBeautyResultToItemsMapper implements Function> {
private static GankBeautyResultToItemsMapper INSTANCE = new GankBeautyResultToItemsMapper();
private GankBeautyResultToItemsMapper() {
}
public static GankBeautyResultToItemsMapper getInstance() {
return INSTANCE;
}
@Override
public List- apply(GankBeautyResult gankBeautyResult) {
List
gankBeauties = gankBeautyResult.beauties;
List- items = new ArrayList<>(gankBeauties.size());
SimpleDateFormat inputFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SS'Z'");
SimpleDateFormat outputFormat = new SimpleDateFormat("yy/MM/dd HH:mm:ss");
for (GankBeauty gankBeauty : gankBeauties) {
Item item = new Item();
try {
Date date = inputFormat.parse(gankBeauty.createdAt);
item.description = outputFormat.format(date);
} catch (ParseException e) {
e.printStackTrace();
item.description = "unknown date";
}
item.imageUrl = gankBeauty.url;
items.add(item);
}
return items;
}
}
disposable = Network.getGankApi()
.getBeauties(10, page)
.map(GankBeautyResultToItemsMapper.getInstance())
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer>() {
@Override
public void accept(@NonNull List- items) throws Exception {
}
}, new Consumer
() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
}
});
三、压合（zip）：
有的时候，app中会需要同时访问不同接口，然后将结果糅合后转为统一的格式后输出（例如将第三方广告的API的广告夹杂自家平台返回的数据List中）。这种并行的异步处理比较麻烦，不过用了zip()之后就会简单得多。代码大致形式：
Observable.zip( api.getData(),adApi.getAds(),zipFunc())
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(observer);
使用案例：
disposable = Observable.zip(Network.getGankApi().getBeauties(200, 1).map(GankBeautyResultToItemsMapper.getInstance()),
Network.getZhuangbiApi().search("装逼"),
new BiFunction, List, List- >() {
@Override
public List
- apply(List
- gankItems, List
zhuangbiImages) {
List- items = new ArrayList
- ();
for (int i = 0; i < gankItems.size() / 2 && i < zhuangbiImages.size(); i++) {
items.add(gankItems.get(i * 2));
items.add(gankItems.get(i * 2 + 1));
Item zhuangbiItem = new Item();
ZhuangbiImage zhuangbiImage = zhuangbiImages.get(i);
zhuangbiItem.description = zhuangbiImage.description;
zhuangbiItem.imageUrl = zhuangbiImage.image_url;
items.add(zhuangbiItem);
}
return items;
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer
>() {
@Override
public void accept(@NonNull List- items) throws Exception {
swipeRefreshLayout.setRefreshing(false);
adapter.setItems(items);
}
}, new Consumer
() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
swipeRefreshLayout.setRefreshing(false);
Toast.makeText(getActivity(), R.string.loading_failed, Toast.LENGTH_SHORT).show();
}
});
四、Token（flatMap）：
出于安全性、性能等方面的考虑，多数服务器会有一些接口需要传入 token 才能正确返回结果，而 token 是需要从另一个接口获取的，这就需要使用两步连续的请求才能获取数据（①token -> ②目标数据）。使用 flatMap() 可以用较为清晰的代码实现这种连续请求，避免 Callback 嵌套的结构。代码大致形式：
disposable = api.getToken()
.flatMap(token->api.getData(token))
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(observer);
使用案例：
final FakeApi fakeApi = Network.getFakeApi();
disposable = fakeApi.getFakeToken("fake_auth_code")
.flatMap(new Function>() {
@Override
public Observable apply(FakeToken fakeToken) {
return fakeApi.getFakeData(fakeToken);
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(FakeThing fakeData) {
}
}, new Consumer() {
@Override
public void accept(Throwable throwable) {
}
});
五、Token_高级（retryWhen）：
有的 token 并非一次性的，而是可以多次使用，直到它超时或被销毁（多数 token 都是这样的）。这样的 token 处理起来比较麻烦：需要把它保存起来，并且在发现它失效的时候要能够自动重新获取新的 token 并继续访问之前由于 token 失效而失败的请求。如果项目中有多处的接口请求都需要这样的自动修复机制，使用传统的 Callback 形式需要写出非常复杂的代码。而使用 RxJava ，可以用 retryWhen() 来轻松地处理这样的问题。代码大致形式：
disposable = api.getData(token)
.retryWhen(observable->
observable.flatMap(->
api.getToken()
.doOnNext(->updateToken())))
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(observer);
使用案例：
final FakeApi fakeApi = Network.getFakeApi();
disposable = Observable.just(1)
.flatMap(new Function>() {
@Override
public Observable apply(Object o) {
return cachedFakeToken.token == null
? Observable.error(new NullPointerException("Token is null!"))
: fakeApi.getFakeData(cachedFakeToken);
}
})
.retryWhen(new Function, Observable>() {
@Override
public Observable apply(Observable observable) {
return observable.flatMap(new Function>() {
@Override
public Observable apply(Throwable throwable) {
if (throwable instanceof IllegalArgumentException || throwable instanceof NullPointerException) {
return fakeApi.getFakeToken("fake_auth_code")
.doOnNext(new Consumer() {
@Override
public void accept(FakeToken fakeToken) {
tokenUpdated = true;
cachedFakeToken.token = fakeToken.token;
cachedFakeToken.expired = fakeToken.expired;
}
});
}
return Observable.error(throwable);
}
});
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(FakeThing fakeData) {
swipeRefreshLayout.setRefreshing(false);
String token = cachedFakeToken.token;
if (tokenUpdated) {
token += "(" + getString(R.string.updated) + ")";
}
tokenTv.setText(getString(R.string.got_token_and_data, token, fakeData.id, fakeData.name));
}
}, new Consumer() {
@Override
public void accept(Throwable throwable) {
swipeRefreshLayout.setRefreshing(false);
Toast.makeText(getActivity(), R.string.loading_failed, Toast.LENGTH_SHORT).show();
}
});
五、缓存（BehaviorSubject）：
RxJava 中有一个较少被人用到的类叫做 Subject，它是一种『既是 Observable，又是 Observer』的东西，因此可以被用作中间件来做数据传递。例如，可以用它的子类 BehaviorSubject 来制作缓存。代码大致形式：
disposable = api.getData()
.subscribe(behaviorSubject);// 网络数据会被缓存
behaviorSubject.subscribe(observer); // 之前的缓存将直接送达 observer。
public Disposable subscribeData(@NonNull Consumer> onNext, @NonNull Consumer onError) {
if (cache == null) {
cache = BehaviorSubject.create();
Observable.create(new ObservableOnSubscribe>() {
@Override
public void subscribe(ObservableEmitter> e) throws Exception {
List- items = Database.getInstance().readItems();
if (items == null) {
setDataSource(DATA_SOURCE_NETWORK);
loadFromNetwork();
} else {
setDataSource(DATA_SOURCE_DISK);
e.onNext(items);
}
}
})
.subscribeOn(Schedulers.io())
.subscribe(cache);
} else {
setDataSource(DATA_SOURCE_MEMORY);
}
return cache.doOnError(new Consumer
() {
@Override
public void accept(@io.reactivex.annotations.NonNull Throwable throwable) throws Exception {
cache = null;
}
})
.observeOn(AndroidSchedulers.mainThread())
.subscribe(onNext, onError);
}
disposable = Data.getInstance()
.subscribeData(new Consumer>() {
@Override
public void accept(@NonNull List- items) throws Exception {
swipeRefreshLayout.setRefreshing(false);
int loadingTime = (int) (System.currentTimeMillis() - startingTime);
loadingTimeTv.setText(getString(R.string.loading_time_and_source, loadingTime, Data.getInstance().getDataSourceText()));
adapter.setItems(items);
}
}, new Consumer
() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
throwable.printStackTrace();
swipeRefreshLayout.setRefreshing(false);
Toast.makeText(getActivity(), R.string.loading_failed, Toast.LENGTH_SHORT).show();
}
});
详细代码请参考凯哥RxJavaSamples案例