浅谈Retrofit2+Rxjava2

近几年，Retrofit犹如燎原之火搬席卷了整个Android界。要是不懂Retrofit，简直不好意思出门。。。
由于近几个项目都没用到Retrofit，无奈只能业余时间自己撸一下，写的不好的地方，还请不吝赐教。
要集成retrofit，在app的build.gradle中添加库以来就可以
compile 'com.squareup.retrofit2:retrofit:2.3.0'

如果需要集成json解析，还需要添加库：

compile 'com.squareup.retrofit2:converter-gson:2.3.0'

如果还需要集成rxjava，还需要添加库：

compile 'com.squareup.retrofit2:adapter-rxjava2:2.3.0'
compile 'io.reactivex.rxjava2:rxandroid:2.0.1'

添加库完毕，接下来需要定义请求接口：

public interface TestService {
    /**
     * 获取新闻  使用rxjava
     * @return
     */
    @POST(AppConstance.NEWS_URL)
    Observable<NewsBean> getNewsWithRxJava(@Query("key") String key, @Query("type") String type);

/**
     * 获取新闻  不使用rxjava
     * @return
     */
    @POST(AppConstance.NEWS_URL)
    Call<ResponseBody> getNewsWithoutRxJava(@Query("key") String key, @Query("type") String type);
}

这个接口是我在聚合数据申请的测试接口，我将其分为两种情况：使用rajava、不使用rxjava。
正常使用中，都会将Retrofit进行封装，我在这里将其简单的封装：

public class RetrofitUtil {
    private volatile static RetrofitUtil sInstance;
    private Retrofit mRetrofit;
    private TestService mTestService;
    private RetrofitUtil(){
        mRetrofit = new Retrofit.Builder()
                .baseUrl(AppConstance.APP_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .build();
        mTestService = mRetrofit.create(TestService.class);
    }
    public static RetrofitUtil getInstance(){
        if (sInstance == null){
            synchronized(RetrofitUtil.class){
                if (sInstance == null){
                    sInstance = new RetrofitUtil();
                }
            }
        }
        return sInstance;
    }
    public TestService getTestService(){
        return mTestService;
    }
}

万事具备，现在开始在Activity中测试Retrofit。
xml文件：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="org.shenchanghui.retrofit2withrxjava2_demo.MainActivity">

<Button
        android:id="@+id/btn_get_news_with_rx_java"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:text="获取新闻(使用rxjava)" />

<Button
        android:id="@+id/btn_get_news_without_rx_java"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/btn_get_news_with_rx_java"
        android:text="获取新闻（不使用Rxjava）" />
</RelativeLayout>

在Activity中请求数据，首先，不使用rajava：

findViewById(R.id.btn_get_news_without_rx_java).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                long time1 = System.currentTimeMillis();
                Call<ResponseBody> call = RetrofitUtil.getInstance().getTestService()
                        .getNewsWithoutRxJava("8bf17cf1c321723f060d5dc5c4da871a", "top");
                long time2 = System.currentTimeMillis();
                Log.e("MainActivity", "请求耗时：" + (time2 - time1) + "ms");
                call.enqueue(new Callback<ResponseBody>() {
                    @Override
                    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                        try {
                            String result = response.body().string();
                            Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT).show();
                            Log.e("MainActivity", "Thread.currentThread():" + Thread.currentThread());
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }

@Override
                    public void onFailure(Call<ResponseBody> call, Throwable t) {
                        Toast.makeText(MainActivity.this, t.toString(), Toast.LENGTH_SHORT).show();
                    }
                });
            }
        });

创建实体类，用GsonFormat插件将获取的json字符串生成实体类，用以解析json。
实体类：

public class NewsBean {

private String reason;
    private ResultBean result;
    private int error_code;

@Override
    public String toString() {
        return "NewsBean{" +
                "reason='" + reason + '\'' +
                ", result=" + result +
                ", error_code=" + error_code +
                '}';
    }

public String getReason() {
        return reason;
    }

public void setReason(String reason) {
        this.reason = reason;
    }

public ResultBean getResult() {
        return result;
    }

public void setResult(ResultBean result) {
        this.result = result;
    }

public int getError_code() {
        return error_code;
    }

public void setError_code(int error_code) {
        this.error_code = error_code;
    }

public static class ResultBean {

private String stat;
        private List<DataBean> data;

@Override
        public String toString() {
            return "ResultBean{" +
                    "stat='" + stat + '\'' +
                    ", data=" + data +
                    '}';
        }

public String getStat() {
            return stat;
        }

public void setStat(String stat) {
            this.stat = stat;
        }

public List<DataBean> getData() {
            return data;
        }

public void setData(List<DataBean> data) {
            this.data = data;
        }

public static class DataBean {

private String uniquekey;
            private String title;
            private String date;
            private String category;
            private String author_name;
            private String url;
            private String thumbnail_pic_s;
            private String thumbnail_pic_s02;
            private String thumbnail_pic_s03;

@Override
            public String toString() {
                return "DataBean{" +
                        "uniquekey='" + uniquekey + '\'' +
                        ", title='" + title + '\'' +
                        ", date='" + date + '\'' +
                        ", category='" + category + '\'' +
                        ", author_name='" + author_name + '\'' +
                        ", url='" + url + '\'' +
                        ", thumbnail_pic_s='" + thumbnail_pic_s + '\'' +
                        ", thumbnail_pic_s02='" + thumbnail_pic_s02 + '\'' +
                        ", thumbnail_pic_s03='" + thumbnail_pic_s03 + '\'' +
                        '}';
            }

public String getUniquekey() {
                return uniquekey;
            }

public void setUniquekey(String uniquekey) {
                this.uniquekey = uniquekey;
            }

public String getTitle() {
                return title;
            }

public void setTitle(String title) {
                this.title = title;
            }

public String getDate() {
                return date;
            }

public void setDate(String date) {
                this.date = date;
            }

public String getCategory() {
                return category;
            }

public void setCategory(String category) {
                this.category = category;
            }

public String getAuthor_name() {
                return author_name;
            }

public void setAuthor_name(String author_name) {
                this.author_name = author_name;
            }

public String getUrl() {
                return url;
            }

public void setUrl(String url) {
                this.url = url;
            }

public String getThumbnail_pic_s() {
                return thumbnail_pic_s;
            }

public void setThumbnail_pic_s(String thumbnail_pic_s) {
                this.thumbnail_pic_s = thumbnail_pic_s;
            }

public String getThumbnail_pic_s02() {
                return thumbnail_pic_s02;
            }

public void setThumbnail_pic_s02(String thumbnail_pic_s02) {
                this.thumbnail_pic_s02 = thumbnail_pic_s02;
            }

public String getThumbnail_pic_s03() {
                return thumbnail_pic_s03;
            }

public void setThumbnail_pic_s03(String thumbnail_pic_s03) {
                this.thumbnail_pic_s03 = thumbnail_pic_s03;
            }
        }
    }
}
```
接下里，使用rxjava，请求数据（自动返回解析好的数据）：

findViewById(R.id.btn_get_news_with_rx_java).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                RetrofitUtil.getInstance().getTestService()
                        .getNewsWithRxJava("8bf17cf1c321723f060d5dc5c4da871a", "top")
                        .subscribeOn(Schedulers.io())
                        .observeOn(AndroidSchedulers.mainThread())
                        .subscribe(new Observer<NewsBean>() {
                            private Disposable mDisposable;

@Override
                            public void onSubscribe(Disposable d) {
                                mDisposable = d;
                            }

@Override
                            public void onNext(NewsBean value) {
                                Toast.makeText(MainActivity.this, value.toString(), Toast.LENGTH_SHORT).show();
                                mDisposable.dispose();//注销
                            }

@Override
                            public void onError(Throwable e) {
                                Toast.makeText(MainActivity.this, e.toString(), Toast.LENGTH_SHORT).show();
                                mDisposable.dispose();//注销
                            }

@Override
                            public void onComplete() {

}
                        });

}
        });