[JAVA] POST images from Android to PHP using Retrofit


Research has made it necessary to POST images from Android to PHP on Azure It seems to be fun to use without thinking about asynchronous processing! !! I adopted Retrofit 2 because of the short-circuit thinking, but I was addicted to it unexpectedly, so a memo


--The following code is written on the assumption that it will be POSTed to http://example.com/upload/index.php --Permissions such as network access and access to internal storage are assumed to be given.

Library import

--Add the following sentence at the bottom of the familiar app / build.gradle


dependencies {
  compile 'com.squareup.retrofit2:retrofit:2.1.0+'

interface implementation

--Since the base URL is specified separately, Path is relative and OK


public interface UploadService {

  //Path can be the one without the base URL
  Call<ResponseBody> upload(@Part MultipartBody.Part file);

ServiceGenerator -Quoted from Official -** Only the base URL part needs to be rewritten **


public class ServiceGenerator {
  //Specify the base URL here
  public static final String API_BASE_URL = "http://example.com/";

  private static OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

  private static Retrofit.Builder builder = new Retrofit.Builder().baseUrl(API_BASE_URL);

  public static <S> S createService(Class<S> serviceClass) {
    Retrofit retrofit = builder.client(httpClient.build()).build();
    return retrofit.create(serviceClass);

Upload process

UploagService service = ServiceGenerator.createService(UploadService.class);  

//Files such as images, music, videos, etc. to be POSTed
String filePath = ”path/to/your/file”;
File file = new File(filePath);

RequestBody requestFile = RequestBody.create(MediaType.parse("multipart/form-data"), file);
MultipartBody.Part body = MultipartBody.Part.createFormData("POST destination field name", file.getName(), requestFile);

Call<ResponseBody> call = service.upload(body);
call.enqueue(new Callback<ResponseBody>() {

  //Called when the status code is other than an error code such as 400
  public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
    //Processing on success
    // response.body();You can get inside the body tag of the HTML response with
  //Called when the status code is an error code such as 400
  public void onFailure(Call<ResponseBody> call, Throwable t) {
    //Processing at the time of failure

Reference site

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