retrofit 2

activity code

/*GET request */

Call<ServicelistMain> call = RestService.getInstance().restInterface.getServiceList();
        call.enqueue(new Callback<ServicelistMain>() {
            @Override
            public void onResponse(Call<ServicelistMain> call, Response<ServicelistMain> response) {
                if (response.isSuccessful()) {
                  //if you showing progress dialog dismiss here
                        serviceList.clear();
                        serviceList.addAll(response.body().getServicelist());
                        adapter.notifyDataSetChanged();
                    
                }
            }

            @Override
            public void onFailure(Call<ServicelistMain> call, Throwable t) {
               //if you showing progress dialog dismiss here
               //you can give retry option here
            }
        });
        
/*POST code */

progressDialog.setMessage(getResources().getString(R.string.submitting_otp));
        progressDialog.show();
        String email = emailEdtTxt.getText().toString().trim();
        String password = passwordEdtTxt.getText().toString().trim();
        String otp = otpEdtTxt.getText().toString().trim();

        Call<OtpVerifier> call = RestService.getInstance().restInterface.verifyOtp(
                email,password,otp);
        call.enqueue(new Callback<OtpVerifier>() {
            @Override
            public void onResponse(Call<OtpVerifier> call, Response<OtpVerifier> response) {
                dialog.dismiss();
                if (progressDialog.isShowing())
                    progressDialog.dismiss();
                if (response.isSuccessful()) {
                    int isSuccess = response.body().getIsSuccess();
                    if (isSuccess == 1) {
                        callLogInService();
                    } else {
                        //show api error msg here
                    }
                }
            }

            @Override
            public void onFailure(Call<OtpVerifier> call, Throwable t) {
                if (progressDialog.isShowing())
                    progressDialog.dismiss();
            }
        });
        
/* Multipart Request */

String firstName = firstNameEdtTxt.getText().toString().trim();
            String lastName = lastNameEdtTxt.getText().toString().trim();
            String email = emailEdtTxt.getText().toString().trim();
            String password = passwordEdtTxt.getText().toString().trim();
            String phnNo = phnEdtTxt.getText().toString().trim();
            String strAddress = addressEdtTxt.getText().toString().trim();

            progressDialog.setMessage(getResources().getString(R.string.registering));
            progressDialog.show();

            RequestBody requestBodyFirstName = RequestBody.create(
                    MediaType.parse("text/plain"), firstName);
            RequestBody requestBodyLastName = RequestBody.create(
                    MediaType.parse("text/plain"), lastName);
            RequestBody requestBodyEmail = RequestBody.create(
                    MediaType.parse("text/plain"), email);
            RequestBody requestBodyPassword = RequestBody.create(
                    MediaType.parse("text/plain"), password);
            RequestBody requestBodyUserType = RequestBody.create(
                    MediaType.parse("text/plain"), IServiceCustomerApp.USER_TYPE);
            RequestBody requestBodyDeviceType = RequestBody.create(
                    MediaType.parse("text/plain"), IServiceCustomerApp.DEVICE_TYPE);
            RequestBody requestBodyToken = RequestBody.create(
                    MediaType.parse("text/plain"), token);
            RequestBody requestBodyPhn = RequestBody.create(
                    MediaType.parse("text/plain"), phnNo);
            RequestBody requestBodyAddress = RequestBody.create(
                    MediaType.parse("multipart/form-data"), strAddress);
            RequestBody requestBodyLat = RequestBody.create(
                    MediaType.parse("multipart/form-data"), String.valueOf(latitude));
            RequestBody requestBodyLng = RequestBody.create(
                    MediaType.parse("multipart/form-data"), String.valueOf(longitude));
            /*RequestBody requestBodyOrderDataFile = RequestBody.create(
                    MediaType.parse("multipart/form-data"), file);*/
            Call<Registration> call = RestService.getInstance().restInterface.
                    createUser(requestBodyFirstName,requestBodyLastName,
                            requestBodyEmail,requestBodyPassword,
                            requestBodyUserType,requestBodyPhn,
                            requestBodyDeviceType,requestBodyToken,
                            requestBodyAddress,requestBodyLat,
                            requestBodyLng,null);
            call.enqueue(new Callback<Registration>() {
                @Override
                public void onResponse(Call<Registration> call, Response<Registration> response) {
                    if (progressDialog.isShowing())
                        progressDialog.dismiss();
                    if (response.isSuccessful()) {
                        int isSuccess = response.body().getIsSuccess();
                        if (isSuccess == 1) {
                            CustomPrefs.writeString(SignUpActivity.this,
                                    IServiceCustomerApp.KEY_IS_VERIFIED,
                                    response.body().getUserInfo().getVerifiedAccount());
                            openLogInActivity();
                        } else {
                            //show api error msg here
                        }
                    }
                }

                @Override
                public void onFailure(Call<Registration> call, Throwable t) {
                    if (progressDialog.isShowing())
                        progressDialog.dismiss();
                }
            });

gradle

compile 'com.squareup.retrofit2:retrofit:2.0.2'
compile 'com.squareup.retrofit2:converter-gson:2.0.2'
compile 'com.squareup.okhttp3:logging-interceptor:3.2.0'

restinteface

public interface RestInterface {

    String BASE_URL = "http://www.base.url/";

    @Multipart
    @POST("end_point_of_url")
    Call<Registration> createUser(@Part("fname") RequestBody firstName,
                                  @Part("lname") RequestBody lastName,
                                  @Part("email") RequestBody email,
                                  @Part("pwd") RequestBody password,
                                  @Part("user_type") RequestBody userType,
                                  @Part("ph") RequestBody phnNo,
                                  @Part("device_type") RequestBody deviceType,
                                  @Part("regid") RequestBody regId,
                                  @Part("address") RequestBody address,
                                  @Part("add_lat") RequestBody addressLat,
                                  @Part("add_long") RequestBody addressLng,
                                  @Part MultipartBody.Part image);

    @FormUrlEncoded
    @POST("end_point_of_url")
    Call<OtpVerifier> verifyOtp(@Field("email") String email,
                                @Field("pwd") String password,
                                @Field("otp") String otp);
                                
    @GET("end_point_of_url")
    Call<ServicelistMain> getServiceList();//if there is any query string then use @Query annotation you can use @PATH for dynamic value
}

retrofit 2

/*Restservice class*/

public class RestService {

    private static RestService restService;
    public RestInterface restInterface;
    private static final int CONNECT_TIMEOUT_MILLIS = 2 * 60; // 2 minute
    private static final int READ_TIMEOUT_MILLIS = 2 * 60;

    public RestService() {
        OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder();
        if (BuildConfig.DEBUG) {
            HttpLoggingInterceptor httpLoggingInterceptor = new HttpLoggingInterceptor();
            httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
            clientBuilder.addInterceptor(httpLoggingInterceptor);
        }

        restInterface = new Retrofit.Builder()
                .baseUrl(RestInterface.BASE_URL)
                .client(clientBuilder.retryOnConnectionFailure(true)
                        .readTimeout(READ_TIMEOUT_MILLIS, TimeUnit.SECONDS)
                        .connectTimeout(CONNECT_TIMEOUT_MILLIS, TimeUnit.SECONDS)
                        .build())
                .addConverterFactory(GsonConverterFactory.create())
                .build()
                .create(RestInterface.class);
    }

    public static RestService getInstance() {
        if (restService == null) {
            restService = new RestService();
        }

        return restService;
    }
}