Android Retrofit实现多图片/文件、图文上传功能

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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