什么是 Retrofit ?
Retrofit是Square开发的一个Android和Java的REST客户端库。这个库非常简单并且具有很多特性，相比其他的网络库，更容易让初学者快速掌握。它可以处理GET、POST、PUT、DELETE…等请求，还可以使用picasso加载图片。
一、再次膜拜下Retrofit
Retrofit无论从性能还是使用方便性上都很屌！！！，本文不去介绍其运作原理（虽然很想搞明白），后面会出专题文章解析Retrofit的内部原理；本文只是从使用上解析Retrofit实现多图片/文件、图文上传的功能。
二、概念介绍
1）注解@Multipart
从字面上理解就是与多媒体文件相关的，没错，图片、文件等的上传都要用到该注解，其中每个部分需要使用@Part来注解。。看其注释
2）注解@PartMap
当然可以理解为使用@PartMap注释，传递多个Part，以实现多文件上传。注释
3）RequestBody
从上面注释中就可以看到参数类型是RequestBody，其就是请求体。文件上传就需要参数为RequestBody。官方使用说明如下http://square.github.io/retrofit/
Multipart parts use one of Retrofit's converters or they can implement RequestBody to handle their own serialization.
四、基本实现
了解了以上概念，下面就一一实现
1）接口定义
public interface IHttpService {
@Multipart
@POST("nocheck/file/agree.do")
Call<BaseBean> upLoadAgree(@PartMap Map<String, RequestBody>params);
} BaseBean是根据服务端返回数据进行定义的，这个使用时可以根据自有Server定义。
2）Retrofit实现
public class RetrofitHttpUpLoad {
private static final long DEFAULT_TIMEOUT = 60;
private volatile static RetrofitHttpUpLoad mInstance;
public Retrofit mRetrofit;
public IHttpService mHttpService;
private Map<String, RequestBody> params = new HashMap<String, RequestBody>();
private RetrofitHttpUpLoad() {
mRetrofit = new Retrofit.Builder()
.baseUrl(UrlConfig.ROOT_URL)
.client(genericClient())
.addConverterFactory(GsonConverterFactory.create())
.build();
mHttpService = mRetrofit.create(IHttpService.class);
}
public static RetrofitHttpUpLoad getInstance() {
if (mInstance == null) {
synchronized (RetrofitHttpUpLoad.class) {
if (mInstance == null)
mInstance = new RetrofitHttpUpLoad();
}
}
return mInstance;
}
public static OkHttpClient genericClient() {
HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
logging.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient httpClient = new OkHttpClient.Builder()
.addInterceptor(logging)
.connectTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
.writeTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
.build();
return httpClient;
}
public static <T> void addToEnqueue(Call<T> call, final RetrofitCallBack retrofitCallBack, final int method) {
final Context context = MyApplication.getContext();
call.enqueue(new Callback<T>() {
@Override
public void onResponse(Call<T> call, Response<T> response) {
LogUtil.d("retrofit back code ====" + response.code());
if (null != response.body()) {
if (response.code() == 200) {
LogUtil.d("retrofit back body ====" + new Gson().toJson(response.body()));
retrofitCallBack.onResponse(response, method);
} else {
LogUtil.d("toEnqueue, onResponse Fail:" + response.code());
ToastUtil.makeShortText(context, "网络连接错误" + response.code());
retrofitCallBack.onFailure(response, method);
}
} else {
LogUtil.d("toEnqueue, onResponse Fail m:" + response.message());
ToastUtil.makeShortText(context, "网络连接错误" + response.message());
retrofitCallBack.onFailure(response, method);
}
}
@Override
public void onFailure(Call<T> call, Throwable t) {
LogUtil.d("toEnqueue, onResponse Fail unKnown:" + t.getMessage());
t.printStackTrace();
ToastUtil.makeShortText(context, "网络连接错误" + t.getMessage());
retrofitCallBack.onFailure(null, method);
}
});
}
public RetrofitHttpUpLoad addParameter(String key, Object o) {
if (o instanceof String) {
RequestBody body = RequestBody.create(MediaType.parse("text/plain;charset=UTF-8"), (String) o);
params.put(key, body);
} else if (o instanceof File) {
RequestBody body = RequestBody.create(MediaType.parse("multipart/form-data;charset=UTF-8"), (File) o);
params.put(key + "\"; filename=\"" + ((File) o).getName() + "", body);
}
return this;
}
public Map<String, RequestBody> bulider() {
return params;
}
} 其中定义了Retrofit实例、还用拦截器定义了统一的超时时间和日志打印；将call加入队列并实现回调。最重要的就是添加参数：
public RetrofitHttpUpLoad addParameter(String key, Object o) {
if (o instanceof String) {
RequestBody body = RequestBody.create(MediaType.parse("text/plain;charset=UTF-8"), (String) o);
params.put(key, body);
} else if (o instanceof File) {
RequestBody body = RequestBody.create(MediaType.parse("multipart/form-data;charset=UTF-8"), (File) o);
params.put(key + "\"; filename=\"" + ((File) o).getName() + "", body);
}
return this;
} 这里就是根据传入的参数，返回不同的RequestBody。
3）使用
private void upLoadAgree() {
showWaitDialog();
RetrofitHttpUpLoad retrofitHttpUpLoad = RetrofitHttpUpLoad.getInstance();
if (!StringUtil.isEmpty(pathImage[0])){
retrofitHttpUpLoad = retrofitHttpUpLoad.addParameter("pic1",new File(pathImage[0]));
}
if (!StringUtil.isEmpty(pathImage[1])){
retrofitHttpUpLoad = retrofitHttpUpLoad.addParameter("pic2", new File(pathImage[1]));
}
if (!StringUtil.isEmpty(pathImage[2])){
retrofitHttpUpLoad = retrofitHttpUpLoad.addParameter("zip", new File(pathImage[2]));
}
Map<String, RequestBody> params = retrofitHttpUpLoad
.addParameter("status", "4")
.addParameter("pickupId", tv_orderquality_pid.getText().toString())
.addParameter("cause", reason)
.addParameter("connectname", et_orderquality_lxrname.getText().toString())
.addParameter("connectphone", et_orderquality_lxrphone.getText().toString())
.addParameter("details", et_orderquality_xqms.getText().toString())
.bulider();
RetrofitHttpUpLoad.addToEnqueue(RetrofitHttpUpLoad.getInstance().mHttpService.upLoadAgree(params),
this, HttpStaticApi.HTTP_UPLOADAGREE);
} 需要注意的是要对图片及文件路径进行判空操作，负责会报异常W/System.err: java.io.FileNotFoundException: /: open failed: EISDIR (Is a directory)
以上所述是小编给大家介绍的Android基于Retrofit实现多图片/文件、图文上传功能，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对编程网网站的支持！
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