Retrofit POST Method with Json data got error code 400 : Bad Request

Question

I would like to call a POST Method(Magento REST API) in Retrofit with a JSON data(provide JSON as JsonObject). For that, I call as follow from the postman and work fine for

Answer 1

Try this

1.APIInterface.java

public interface APIInterface {

    /*Login*/
    @POST("users/login")
    Call savePost(@HeaderMap Map header, @Body UserModel loginRequest);

}

2.ApiClient.java

public class ApiClient {

    public static final String BASE_URL = "baseurl";
    private static Retrofit retrofit = null;


    public static Retrofit getClient() {
        if (retrofit == null) {
            HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
            interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
            OkHttpClient client = new OkHttpClient.Builder().addInterceptor(interceptor)
                    .connectTimeout(30, TimeUnit.MINUTES)
                    .readTimeout(30, TimeUnit.MINUTES)
                    .build();

            retrofit = new Retrofit.Builder()
                    .baseUrl(BASE_URL)
                    .client(client)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }

}

3. API call

   public void sendPost(JSONObject jsonObject) {
   
       LoginRequestModel loginRequest = new LoginRequestModel(userName, userPassword);
   
       Map header = new HashMap<>();
       header.put("Content-Type", "application/json");
   
       APIInterface appInterface = ApiClient.getClient().create(APIInterface.class);
       System.out.println("Final" + new Gson().toJson(loginRequest));
   
       Call call = appInterface.savePost(header, loginRequest);
   
       call.enqueue(new Callback() {
           @Override
           public void onResponse(Call call, Response response) {
               hideProgressDialog();
   
               if (response.body()!=null) {
   
               } else {
                   Toast.makeText(mContext, "Invalid credentials", Toast.LENGTH_SHORT).show();
               }
   
           }
   
           @Override
           public void onFailure(Call call, Throwable t) {
               t.printStackTrace();
           }
       });
   

   }

4. Dependencies in Gradle file

   compile 'com.squareup.retrofit2:retrofit:2.3.0'
   compile 'com.google.code.gson:gson:2.8.2'
   compile 'com.squareup.retrofit2:converter-gson:2.3.0'
   compile 'com.squareup.okhttp3:okhttp:3.9.0'
   compile 'com.squareup.okhttp3:logging-interceptor:3.9.0'
   

5.User Model

public class UserModel {

    @SerializedName("usename")
    @Expose
    String userEmail;

    @SerializedName("password")
    @Expose
    String userPassword;

    public UserModel(String userEmail, String userPassword) {
        this.userEmail = userEmail;
        this.userPassword = userPassword;
    }


}