网络请求-Retrofit+OkHttp+RxJava

用https://www.wanandroid.com/网站提供的api

1、retrofit GET请求

public interface WanAndroidApi {
    //总数据
    @GET("project/tree/json")    //https://www.wanandroid.com/project/tree/json
    Observable<ProjectBean> getProject();
    //item数据API
    @GET("project/list/{pageIndex}/json")   //https://www.wanandroid.com/project/list/1/json?cid=294
    Observable<ProjectItem> getProjectItem(@Path("pageIndex") int pageIndex, @Query("cid") int cid);//会自动拼接成?cid=294
}

2、bean数据Android Studio插件GsonForm生成，此处代码省略

3、创建Retrofit函数

public class HttpUtil {
    public static String BASE_URL = "https://www.wanandroid.com/";

    //BASE_URL可设置
    public static void setBaseUrl(String baseUrl) {
        BASE_URL = baseUrl;
    }

    //创建Retrofit的函数
    public static Retrofit createRetrofit(){
        OkHttpClient.Builder builder = new OkHttpClient.Builder();
        OkHttpClient okHttpClient = builder.addNetworkInterceptor(new StethoInterceptor())
                .readTimeout(10, TimeUnit.SECONDS)
                .writeTimeout(10, TimeUnit.SECONDS)
                .connectTimeout(10, TimeUnit.SECONDS)
                .build();
        return new Retrofit.Builder().baseUrl(BASE_URL).client(okHttpClient)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .build();
    }
}

4、使用

    WanAndroidApi api = HttpUtil.createRetrofit().create(WanAndroidApi.class);

    //线程切换封装，耗时操作在子线程完成，界面更新在主线程完成
    private final static <UD> ObservableTransformer<UD, UD> rxUD(){
        return new ObservableTransformer<UD, UD>(){

            @Override
            public @NonNull ObservableSource<UD> apply(@NonNull Observable<UD> upstream) {
                return upstream.subscribeOn(Schedulers.io())
                        .observeOn(AndroidSchedulers.mainThread());
            }
        };
    }

/*   lambda表达式
    private final static <UD> ObservableTransformer<UD, UD> rxUD(){
        return upstream -> upstream.subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread());
    }
*/

    public void getProjectAction(View view) {

        api.getProject().compose(rxUD())
                .subscribe(projectBean -> {
                    Log.d(TAG, "getProjectAction: " + projectBean);
                });
                /*.subscribe(new Consumer<ProjectBean>() {
                    @Override
                    public void accept(ProjectBean projectBean) throws Throwable {
                        Log.d(TAG, "accept: " + projectBean);
                    }
                });*/


    }

    public void getProjectListAction(View view){
        api.getProjectItem(1, 294).compose(rxUD()).subscribe(projectItem -> {
            Log.d(TAG, "getProjectListAction: " + projectItem);
        });
    }

    /**
     * 嵌套查询
     */
    public void antiShakeAction(){
        api.getProject().compose(rxUD()).subscribe(projectBean -> {
            for (ProjectBean.DataBean dataBean : projectBean.getData()) {
                api.getProjectItem(1, dataBean.getId()).compose(rxUD()).subscribe(projectItem -> {
                    Log.d(TAG, "antiShakeAction: " + projectItem);
                });
            }
        });
    }

解决之前OkHttp请求数据后，Handler更新UI比较繁琐的问题

附：

    public void rxJavaDownloadImageAction(View view){
        Observable.just(PATH)       //自己创建数据，并非Retrofit装载
                .map(new Function<String, Bitmap>() {
                    @Override
                    public Bitmap apply(String s) throws Throwable {//网络请求图片
                        URL url = new URL(PATH);
                        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                        httpURLConnection.setConnectTimeout(5000);
                        int responseCode = httpURLConnection.getResponseCode();
                        if (responseCode == HttpURLConnection.HTTP_OK){
                            InputStream inputStream = httpURLConnection.getInputStream();
                            Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                            return bitmap;
                        }
                        return null;
                    }
                })
                .compose(rxUD())
                .subscribe(v -> {
                    imageView.setImageBitmap(v);
                });
    }

        String[] strings = {"Anny", "Victor", "Model"};
/*
        for (String string : strings) {
            Log.d(TAG, "onCreate: for string" + string);
        }
*/

        Observable.fromArray(strings).subscribe(string -> {
            Log.d(TAG, "onCreate: rxJava string" + string);
        });

    }