Retrofit简单介绍及使用

1：Retrofit 2 是一个网络框架 底层是OKHTTP 一个公司出的 square

2：Retrofit 2可以跟 Rxjava交互

3：Rxjava是什么东西 相当于一个网络处理的调味品 基于java 完全异步，基于观察者模式

4：观察者模式
Observer（观察者） 和Observable（被观察者）

如何使用
1：导入各种依赖
2：写一个工具类用来初始化OKHTTP和Retrofit
3：声明一个接口能用注解去请求网络APIService  通过Retrofit里面一个create(xxxApi.class)

这个是在项目的build.grade里面直接粘过去就OK

ext {
// Sdk and tools
minSdkVersion = 19
targetSdkVersion = 26
compileSdkVersion = 26
buildToolsVersion = '26.0.2'
//support版本
supportVersion = '27.1.0'
constraintLayout = '1.0.2'
junit = '4.12'
testRunner = '1.0.1'
espressoCore = '3.0.1'

interceptor = "3.11.0"
retrofit = '2.3.0'
converterGson = '2.3.0'
rxandroid = '1.2.1'
rxjava = '1.3.0'
rxbus = '1.0.6'
adapterRxjava = '2.0.2'
}

implementation "com.squareup.okhttp3:logging-interceptor:$rootProject.interceptor"
implementation "com.squareup.retrofit2:retrofit:$rootProject.retrofit"
implementation "com.squareup.retrofit2:converter-gson:$rootProject.converterGson"
implementation "io.reactivex:rxandroid:$rootProject.rxandroid"
implementation "io.reactivex:rxjava:$rootProject.rxjava"
implementation "com.hwangjr.rxbus:rxbus:$rootProject.rxbus"
implementation "com.squareup.retrofit2:adapter-rxjava:$rootProject.adapterRxjava"
implementation 'com.jakewharton:butterknife:8.8.1'
annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'

存放接口的类

//用来存放所有接口
public class Contacts {
//总接口前缀
public static final String BASE_URL = "http://www.zhaoapi.cn/";
//登陆
public static final String USER_LOGIN = "user/login";
//用户信息
public static final String USER_INFO = "user/getUserInfo";
//上传图片
public static final String UP_LOAD_IMAGE = "file/upload";

}

处理接口

/**
* 他用来处理接口
*/
public interface MyApiService {
//Retrofit + Rxjava
@GET
Observable<ResponseBody> get(@Url String url,@QueryMap Map<String,String> map);
//Observable 被观察者
@POST
Observable<ResponseBody> post(@Url String url, @QueryMap Map<String,String> map);

//这是Retrofit的使用
@GET
Call<ResponseBody> get();
}

接下来介绍工具类，注意包不要导错

import android.os.Environment;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.RequestBody;
import okhttp3.ResponseBody;
import okhttp3.logging.HttpLoggingInterceptor;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;
import rx.Observer;
import rx.Scheduler;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;
import soexample.umeng.com.retrofitokhttpdemo.Contacts;

public class RetrofitUtils {

private MyApiService myApiService;

private RetrofitUtils() {
HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor();
loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient okHttpClient = new OkHttpClient.Builder()
.readTimeout(20, TimeUnit.SECONDS)
.connectTimeout(20, TimeUnit.SECONDS)
.writeTimeout(20, TimeUnit.SECONDS)
.addInterceptor(loggingInterceptor)
//配置此客户端，以便在遇到连接问题时重试或不重试。默认情况下，
//*该客户端从以下问题中悄悄恢复
.retryOnConnectionFailure(true)
.build();
//初始化Retrofit 并结合各种操作
Retrofit retrofit = new Retrofit.Builder()
//结合Gson解析
.addConverterFactory(GsonConverterFactory.create())
//结合Rxjava
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.baseUrl(Contacts.BASE_URL)
.client(okHttpClient)
.build();
//通过Retrofit创建完 这个ApiService 就可以调用方法了
myApiService = retrofit.create(MyApiService.class);
}

public static RetrofitUtils getInstance() {
return RetroHolder.retro;
}

private static class RetroHolder {
private static final RetrofitUtils retro = new RetrofitUtils();
}
//封装Get方式  这里面采用构造者模式  就是调用这个方法有返回自己本身这个对象
public RetrofitUtils get(String url, Map<String, String> map) {
//这个订阅事件（处理网络请求）放生那个线程
//Schedulers 线程调度器
myApiService.get(url, map).subscribeOn(Schedulers.io())//io就是子线程
//在主线程调用
.observeOn(AndroidSchedulers.mainThread())
.subscribe(observer);
return RetrofitUtils.getInstance();
}

/**
* 表单post请求
*/
public RetrofitUtils post(String url, Map<String, String> map) {
if (map == null) {
map = new HashMap<>();
}

myApiService.post(url, map)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(observer);
return RetrofitUtils.getInstance();
}
//子类使用
private Subscriber<ResponseBody> subscriber = new Subscriber<ResponseBody>() {
@Override
public void onCompleted() {

}

@Override
public void onError(Throwable e) {

}

@Override
public void onNext(ResponseBody responseBody) {

}
};
//重写一个观察者对象
private Observer observer = new Observer<ResponseBody>() {

@Override
public void onCompleted() {

}
//网络处理失败
@Override
public void onError(Throwable e) {
if (httpListener != null) {
httpListener.onError(e.getMessage());
}
}
//网络处理成功
@Override
public void onNext(ResponseBody responseBody) {
if (httpListener != null) {
try {
httpListener.onSuccess(responseBody.string());
} catch (IOException e) {
e.printStackTrace();
}
}

}
};

public interface HttpListener {
void onSuccess(String jsonStr);

void onError(String error);
}

private HttpListener httpListener;

public void setHttpListener(HttpListener listener) {
this.httpListener = listener;
}

}

动态权限

private void checkPermission(int type) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.INTERNET) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.INTERNET}, type);
} else {
startRequest(type);
}
} else {
startRequest(type);
}
}

成功之后的调用

@Override
public void onSuccess(Object data) {
//因为是复用一个处理的  用java的一个关键字instanceof处理一下即可
if (data instanceof LoginBean) {
Toast.makeText(this, ((LoginBean) data).getMsg(), Toast.LENGTH_SHORT).show();
} else if (data instanceof UserInfoBean) {
UserInfoBean userIfo = (UserInfoBean) data;
Toast.makeText(this, userIfo.getMsg(), Toast.LENGTH_SHORT).show();
}
}