RxJava + Retrofit 完成网络请求

前言

RxJava和Retrofit也火了一段时间了。一直没有时间研究这些新东西，最近有时间准备写个项目练手，打算先用Android写一个Demo出来，却发现Android的世界发生了天翻地覆的变化，EventBus和OKHttp3 都不见了，RxJava和Retrofit是什么东东？

如果你对Retrofit不熟悉就先看官网的介绍

如果你对RxJava不熟悉请先看官网介绍以及 gank.io 给 Android 开发者的 RxJava 详解这篇文章

当然也有很多RxJava与Retrofit的文章，我是参考tough1985大神的这篇文章

学(好)习(记)就(性)要(不)做(如)个(烂)笔(笔)记(头)

RxJava如何与Retrofit结合

本文实现的目标

RxJava如何与Retrofit结合
相同格式的Http请求数据该如何封装
相同格式的Http请求数据统一进行预处理
如何取消一个Http请求 – 观察者之间的对决，Oberver VS Subscriber
一个需要ProgressDialog的Subscriber该有的样子

添加依赖包

先贴出build.gradle文件的内容

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.3.0'
    compile 'com.android.support:support-v4:23.3.0'
    compile 'com.android.support:recyclerview-v7:23.3.0'
    //日志
    compile 'com.orhanobut:logger:1.15'
    //广告
    compile 'com.bigkoo:convenientbanner:2.0.5'
    compile 'com.ToxicBakery.viewpager.transforms:view-pager-transforms:1.2.32@aar'
    //注解绑定view
    compile 'com.jakewharton:butterknife:8.2.1'
    apt 'com.jakewharton:butterknife-compiler:8.2.1'
    //ViewPage指示器
    compile 'com.astuetz:pagerslidingtabstrip:1.0.1'
    //rx系列
    compile 'io.reactivex:rxjava:1.1.6'
    compile 'io.reactivex:rxandroid:1.2.1'
    compile 'com.squareup.retrofit2:retrofit:2.1.0'
    compile 'com.squareup.retrofit2:retrofit-adapters:2.1.0'
    compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'
    compile 'com.squareup.retrofit2:converter-gson:2.1.0'
    compile 'com.google.code.gson:gson:2.7'
}

本文是基于RxJava 1.1.6 和 Retrofit 2.1.0 来进行的。添加rxandroid是因为rxjava中的线程问题。

如需查看项目代码 –> 代码地址:
https://github.com/Javen205/SmartCloud 选择Tag1

原生的Retrofit请求

添加Retrofit 接口

/**
 * 请求示例：http://japi.juhe.cn/joke/content/list.from?
 * key=您申请的KEY&page=2&pagesize=10&sort=asc&time=1418745237
 */
public interface JokeService {
    //Retrofit原生请求
    @GET("content/list.from")
    Call<JokeEntity> getJokes(@QueryMap Map<String, Object> options);
}

Fragment 或者Activity中调用

/**
 * 
 * 原生的Retrofit请求
 */
private void getJokes(Map<String, Object> options) {
    String baseUrl="http://japi.juhe.cn/joke/";
    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(baseUrl)
            .addConverterFactory(GsonConverterFactory.create())
            .build();
    JokeService jokeService = retrofit.create(JokeService.class);
    Call<JokeEntity> call = jokeService.getJokes(options);
    call.enqueue(new Callback<JokeEntity>() {
        @Override
        public void onResponse(Call<JokeEntity> call, Response<JokeEntity> response) {
            JokeEntity jokeEntity = response.body();
            Logger.i(jokeEntity.toString());
            if(jokeEntity.getError_code()==0) {
                List<JokeEntity.Data.Subject> data = jokeEntity.getResult().getData();
                for (JokeEntity.Data.Subject subject : data) {
                    Logger.i(subject.toString());
                }
                textview.setText(data.get(0).toString());
            }
        }
        @Override
        public void onFailure(Call<JokeEntity> call, Throwable t) {
            textview.setText(t.getMessage());
        }
    });
}

添加Rxjava

Retrofit本身对Rxjava提供了支持。

添加Retrofit对Rxjava的支持需要在Gradle文件中添加

1	compile 'io.reactivex:rxjava:1.1.6'

上文中已经添加

然后在创建Retrofit的过程中添加如下代码：

Retrofit retrofit = new Retrofit.Builder()
        .baseUrl(baseUrl)
        .addConverterFactory(GsonConverterFactory.create())
        .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
        .build();

这样一来我们定义的service返回值就不在是一个Call了，而是一个Observable

重新定义 JokeService 方法

/**
 * 请求示例：http://japi.juhe.cn/joke/content/list.from?
 * key=您申请的KEY&page=2&pagesize=10&sort=asc&time=1418745237
 */
public interface JokeService {
    @GET("content/list.from")
    Observable<HttpJokeResult<JokeEntity.Data>> getJokes(@QueryMap Map<String, Object> options);
}

getJokes方法改为：

/**
     * Retrofit + RxJava
     * @param options
     */
    private void getJokes2(Map<String, Object> options) {
        String baseUrl="http://japi.juhe.cn/joke/";
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(baseUrl)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .build();
        JokeService jokeService = retrofit.create(JokeService.class);
        jokeService.getJokesByRxJava(options)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Subscriber<JokeEntity>() {
                    @Override
                    public void onCompleted() {
                        Toast.makeText(mContext, "Get Top Joke Completed", Toast.LENGTH_SHORT).show();
                    }
                    @Override
                    public void onError(Throwable e) {
                        textview.setText(e.getMessage());
                    }
                    @Override
                    public void onNext(JokeEntity jokeEntity) {
                        Logger.i(jokeEntity.toString());
                        if(jokeEntity.getError_code()==0) {
                            List<JokeEntity.Data.Subject> data = jokeEntity.getResult().getData();
                            for (JokeEntity.Data.Subject subject : data) {
                                Logger.i(subject.toString());
                            }
                            textview.setText(data.get(0).toString());
                        }else {
                            textview.setText(jokeEntity.toString());
                        }
                    }
                });
    }

这样基本上就完成了Retrofit和Rxjava的结合，但是这样封装还是不太满意。

接下来我们把创建Retrofit的过程封装一下，然后希望Activity/Fargment创建Subscriber对象传进来。

将请求过程进行封装

创建一个对象HttpMethods

package com.javen.smartcloud.http;
import com.javen.smartcloud.entity.HttpJokeResult;
import com.javen.smartcloud.entity.JokeEntity;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import okhttp3.OkHttpClient;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;
import rx.Observable;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.functions.Func1;
import rx.schedulers.Schedulers;
public class HttpMethods {
    public static final String BASE_URL = "http://japi.juhe.cn/joke/";
    private static final int DEFAULT_TIMEOUT = 5;
    private Retrofit retrofit;
    private JokeService jokeService;
    //构造方法私有
    private HttpMethods() {
        //手动创建一个OkHttpClient并设置超时时间
        OkHttpClient.Builder httpClientBuilder = new OkHttpClient.Builder();
        httpClientBuilder.connectTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS);
        retrofit = new Retrofit.Builder()
                .client(httpClientBuilder.build())
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .baseUrl(BASE_URL)
                .build();
        jokeService = retrofit.create(JokeService.class);
    }
    //在访问HttpMethods时创建单例
    private static class SingletonHolder{
        private static final HttpMethods INSTANCE = new HttpMethods();
    }
    //获取单例
    public static HttpMethods getInstance(){
        return SingletonHolder.INSTANCE;
    }
    /**
     * 用来统一处理Http的resultCode,并将HttpResult的Data部分剥离出来返回给subscriber
     *
     * @param <T> Subscriber真正需要的数据类型，也就是Data部分的数据类型
     */
    private class HttpResultFunc<T> implements Func1<HttpJokeResult<T>, T> {
        @Override
        public T call(HttpJokeResult<T> httpResult) {
            if (httpResult.getError_code() != 0) {
                throw new ApiException(httpResult.getError_code());
            }
            return httpResult.getResult();
        }
    }
    private <T> void toSubscribe(Observable<T> observable, Subscriber<T> subscriber){
        observable.subscribeOn(Schedulers.io())
                .unsubscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(subscriber);
    }
    /**
     * 用于获取聚合笑话的数据
     * @param subscriber 由调用者传过来的观察者对象
     * @param options 访问参数
     */
    public void getJokes(Subscriber<JokeEntity> subscriber, Map<String, Object> options){
//        jokeService.getJokesByRxJava(options)
//                .subscribeOn(Schedulers.io())
//                .unsubscribeOn(Schedulers.io())
//                .observeOn(AndroidSchedulers.mainThread())
//                .subscribe(subscriber);
        Observable<JokeEntity> observable = jokeService.getJokesByRxJava(options);
        toSubscribe(observable,subscriber);
    }
}

用一个单例来封装该对象，在构造方法中创建Retrofit和对应的Service。如果需要访问不同的基地址，那么你可能需要创建多个Retrofit对象，或者干脆根据不同的基地址封装不同的HttpMethod类。

再来看Activity/Fargment中的getJokes方法：以下代码中的 getJokes3

package com.javen.smartcloud.fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.javen.smartcloud.R;
import com.javen.smartcloud.entity.HttpJokeResult;
import com.javen.smartcloud.entity.JokeEntity;
import com.javen.smartcloud.http.HttpMethods;
import com.javen.smartcloud.http.JokeService;
import com.javen.smartcloud.subscribers.ProgressSubscriber;
import com.orhanobut.logger.Logger;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
public class FragmentOne extends BaseFragment {
    @BindView(R.id.id_joke_tv)
    TextView textview;
    @BindView(R.id.id_joke_btn)
    Button jokeBtn;
    Subscriber<JokeEntity> subscriber;
    Subscriber<HttpJokeResult<JokeEntity.Data>> subscriber2;
    Subscriber<JokeEntity.Data> subscriber3;
    public FragmentOne() {
    }
    @Override
    public View initView(LayoutInflater inflater, ViewGroup container) {
        View view = inflater.inflate(R.layout.fragment_one, container, false);
        ButterKnife.bind(this, view);
        return view;
    }
    @Override
    public void initData() {
    }
    @OnClick(R.id.id_joke_btn)
    public void onClick() {
        long timeMillis = System.currentTimeMillis();
        String time=String.valueOf(timeMillis).substring(0,10);
        Logger.e("当前时间戳:"+timeMillis+"  前10位:"+time);
        Toast.makeText(mContext, "点我", Toast.LENGTH_SHORT).show();
        Map<String,Object> options = new HashMap<String, Object>();
        options.put("key","bd19bfd8cb856884b5739b0267ec24c9");
        options.put("sort","desc");
        options.put("page",1);
        options.put("pagesize",2);
        options.put("time",time);
//        getJokes1(options);
//        getJokes2(options);
//        getJokes3(options);
    }
   
    /**
     * Retrofit + RxJava 封装版
     * 3.添加HttpMethods
     * @param options
     */
    private void getJokes3(Map<String, Object> options){
        subscriber = new Subscriber<JokeEntity>() {
            @Override
            public void onCompleted() {
                Toast.makeText(mContext, "Get Top Joke Completed", Toast.LENGTH_SHORT).show();
            }
            @Override
            public void onError(Throwable e) {
                textview.setText(e.getMessage());
            }
            @Override
            public void onNext(JokeEntity jokeEntity) {
                Logger.i(jokeEntity.toString());
                if(jokeEntity.getError_code()==0) {
                    List<JokeEntity.Data.Subject> data = jokeEntity.getResult().getData();
                    for (JokeEntity.Data.Subject subject : data) {
                        Logger.i(subject.toString());
                    }
                    textview.setText(data.get(0).toString());
                }else {
                    textview.setText(jokeEntity.toString());
                }
            }
        };
        HttpMethods.getInstance().getJokes(subscriber,options);
    }
    /**
     * Retrofit + RxJava
     * @param options
     */
    private void getJokes2(Map<String, Object> options) {
        String baseUrl="http://japi.juhe.cn/joke/";
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(baseUrl)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .build();
        JokeService jokeService = retrofit.create(JokeService.class);
        jokeService.getJokesByRxJava(options)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Subscriber<JokeEntity>() {
                    @Override
                    public void onCompleted() {
                        Toast.makeText(mContext, "Get Top Joke Completed", Toast.LENGTH_SHORT).show();
                    }
                    @Override
                    public void onError(Throwable e) {
                        textview.setText(e.getMessage());
                    }
                    @Override
                    public void onNext(JokeEntity jokeEntity) {
                        Logger.i(jokeEntity.toString());
                        if(jokeEntity.getError_code()==0) {
                            List<JokeEntity.Data.Subject> data = jokeEntity.getResult().getData();
                            for (JokeEntity.Data.Subject subject : data) {
                                Logger.i(subject.toString());
                            }
                            textview.setText(data.get(0).toString());
                        }else {
                            textview.setText(jokeEntity.toString());
                        }
                    }
                });
    }
    /**
     * 原生的Retrofit请求
     */
    private void getJokes1(Map<String, Object> options) {
        String baseUrl="http://japi.juhe.cn/joke/";
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(baseUrl)
                .addConverterFactory(GsonConverterFactory.create())
                .build();
        JokeService jokeService = retrofit.create(JokeService.class);
        Call<JokeEntity> call = jokeService.getJokes(options);
        call.enqueue(new Callback<JokeEntity>() {
            @Override
            public void onResponse(Call<JokeEntity> call, Response<JokeEntity> response) {
                JokeEntity jokeEntity = response.body();
                Logger.i(jokeEntity.toString());
                if(jokeEntity.getError_code()==0) {
                    List<JokeEntity.Data.Subject> data = jokeEntity.getResult().getData();
                    for (JokeEntity.Data.Subject subject : data) {
                        Logger.i(subject.toString());
                    }
                    textview.setText(data.get(0).toString());
                }
            }
            @Override
            public void onFailure(Call<JokeEntity> call, Throwable t) {
                textview.setText(t.getMessage());
            }
        });
    }
    @Override
    public void onDestroy() {
        super.onDestroy();
        if (subscriber!=null){
            subscriber.unsubscribe();
        }
        if (subscriber2!=null){
            subscriber2.unsubscribe();
        }
        if (subscriber3!=null){
            subscriber3.unsubscribe();
        }
    }
}