Using Retrofit in Android

Question

I have an android app that has 3 activities :

1. A login activity
2. A tasks acivity where all tasks pertaining to a user are displayed (Populated using an Array Adapter)
3. A task_details activity which results from clicking a task on the list

I have to consume REST Apis. The research I have done so far directs me to use Retrofit. I checked how to use it and found out that :

1. Set the base URL in the Main Activity (Mine is the Login Activity)
2. I need to create a API class and define my functions using annotations.
3. Use the class Rest Adapter in the Activity and define Callbacks.

Had my app been a single activity app, I would have crunched everything in my MainActivity.java but I don't know how and where to put all the code from steps 1,2,3 for use in my 3 activities.Could you please help by telling how to use Retrofit in my app. Thanks a lot.

Specifically, I need network calls to : 1. Login the user 2. Get all the tasks of the user. And for both I would be using a given REST api.

*********************************************
          Calling Api USing Retrofit
*********************************************
**Dependancies** :-
      implementation 'com.android.support:recyclerview-v7:27.1.1'
        implementation 'com.squareup.picasso:picasso:2.5.2'
        implementation 'com.android.support:cardview-v7:27.1.1'
    enter code here
**Model**
use the Pozo class

**Api Call**
 -> getLogin()    // use the method



  //API call for Login
    private void getLogin()
    {
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE,
                WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
        AsyncHttpClient client = new AsyncHttpClient();
        RequestParams requestParams = new RequestParams();
        requestParams.put("email_id", edit_email.getText().toString());
        requestParams.put("password", edit_password.getText().toString());
        Log.e("", "LOGIN URL==>" + Urls.LOGIN + requestParams);
        Log.d("device_token", "Device_ Token" + FirebaseInstanceId.getInstance().getToken());
        client.post(Urls.LOGIN, requestParams, new JsonHttpResponseHandler() {
            @Override
            public void onStart() {
                super.onStart();
                ShowProgress();
            }

            @Override
            public void onFinish() {
                super.onFinish();
                Hideprogress();

            }

            @Override
            public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
                super.onSuccess(statusCode, headers, response);
                Log.e("", "Login RESPONSE-" + response);
                Login login = new Gson().fromJson(String.valueOf(response), Login.class);
                edit_email.setText("");
                edit_password.setText("");
                if (login.getStatus().equals("true")) {
                    getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
                    MDToast mdToast = MDToast.makeText(SignInActivity.this, String.valueOf("User Login Successfully!"),
                            MDToast.LENGTH_SHORT, MDToast.TYPE_SUCCESS);
                    mdToast.show();
                    Utils.WriteSharePrefrence(SignInActivity.this, Util_Main.Constant.EMAIL, login.getData().getEmailId());
                    Utils.WriteSharePrefrence(SignInActivity.this, Constant.USERID, login.getData().getId());

                    Utils.WriteSharePrefrence(SignInActivity.this, Constant.USERNAME, login.getData().getFirstName());
                    Utils.WriteSharePrefrence(SignInActivity.this, Constant.PROFILE, login.getData().getProfileImage());
                    hideKeyboard(SignInActivity.this);
                    Intent intent = new Intent(SignInActivity.this, DashboardActivity.class);
                    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                    startActivity(intent);
                    finish();
                } else {
                    getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
                    MDToast mdToast = MDToast.makeText(SignInActivity.this, String.valueOf("Login Denied"),
                            MDToast.LENGTH_SHORT, MDToast.TYPE_ERROR);
                    mdToast.show();
                }
            }

            @Override
            public void onFailure(int statusCode, Header[] headers, String responseString, Throwable throwable) {
                super.onFailure(statusCode, headers, responseString, throwable);
                Log.e("", throwable.getMessage());
                getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
                MDToast mdToast = MDToast.makeText(SignInActivity.this, "Something went wrong",
                        MDToast.LENGTH_SHORT, MDToast.TYPE_ERROR);
                mdToast.show();
            }
        });
    }

Answer 1

Using Retrofit is quite simple and straightforward.

First of all you need to add retrofit to your project, as example with Gradle build sytem.

compile 'com.squareup.retrofit:retrofit:1.7.1' |

another way you can download .jar and place it to your libs folder.

Then you need to define interfaces that will be used by Retrofit to make API calls to your REST endpoints. For example for users:

public interface YourUsersApi {

   //You can use rx.java for sophisticated composition of requests 
   @GET("/users/{user}")
   public Observable<SomeUserModel> fetchUser(@Path("user") String user);

   //or you can just get your model if you use json api
   @GET("/users/{user}")
   public SomeUserModel fetchUser(@Path("user") String user);

   //or if there are some special cases you can process your response manually 
   @GET("/users/{user}")
   public Response fetchUser(@Path("user") String user);

}

Ok. Now you have defined your API interface an you can try to use it.

To start you need to create an instance of RestAdapter and set base url of your API back-end. It's also quite simple:

RestAdapter restAdapter = new RestAdapter.Builder()
   .setEndpoint("https://yourserveraddress.com")
    .build();

YourUsersApi yourUsersApi = restAdapter.create(YourUsersApi.class);

Here Retrofit will read your information from interface and under the hood it will create RestHandler according to meta-info your provided which actually will perform HTTP requests.

Then under the hood, once response is received, in case of json api your data will be transformed to your model using Gson library so you should be aware of that fact that limitations that are present in Gson are actually there in Retrofit.

To extend/override process of serialisers/deserialisation your response data to your models you might want to provide your custom serialisers/deserialisers to retrofit.

Here you need to implement Converter interface and implement 2 methods fromBody() and toBody().

Here is example:

public class SomeCustomRetrofitConverter implements Converter {

    private GsonBuilder gb;

    public SomeCustomRetrofitConverter() {
        gb = new GsonBuilder();

        //register your cursom custom type serialisers/deserialisers if needed
        gb.registerTypeAdapter(SomeCutsomType.class, new SomeCutsomTypeDeserializer());
    }

    public static final String ENCODING = "UTF-8";

    @Override
    public Object fromBody(TypedInput body, Type type) throws ConversionException {
        String charset = "UTF-8";
        if (body.mimeType() != null) {
            charset = MimeUtil.parseCharset(body.mimeType());
        }
        InputStreamReader isr = null;
        try {
           isr = new InputStreamReader(body.in(), charset);
           Gson gson = gb.create();
           return gson.fromJson(isr, type);
        } catch (IOException e) {
            throw new ConversionException(e);
        } catch (JsonParseException e) {
            throw new ConversionException(e);
        } finally {
            if (isr != null) {
                   try {
                      isr.close();
                   } catch (IOException ignored) {
                }
            }
        }
    }

    @Override
    public TypedOutput toBody(Object object) {
        try {
            Gson gson = gb.create();
            return new JsonTypedOutput(gson.toJson(object).getBytes(ENCODING), ENCODING);
        } catch (UnsupportedEncodingException e) {
            throw new AssertionError(e);
        }
     }

    private static class JsonTypedOutput implements TypedOutput {
        private final byte[] jsonBytes;
        private final String mimeType;

        JsonTypedOutput(byte[] jsonBytes, String encode) {
            this.jsonBytes = jsonBytes;
            this.mimeType = "application/json; charset=" + encode;
        }

        @Override
        public String fileName() {
            return null;
        }

       @Override
       public String mimeType() {
           return mimeType;
       }

       @Override
       public long length() {
          return jsonBytes.length;
       }

       @Override
       public void writeTo(OutputStream out) throws IOException {
           out.write(jsonBytes);
       }
    }
 }

And now you need to enable your custom adapters, if it was needed by using setConverter() on building RestAdapter

Ok. Now you are aware how you can get your data from server to your Android application. But you need somehow mange your data and invoke REST call in right place. There I would suggest to use android Service or AsyncTask or loader or rx.java that would query your data on background thread in order to not block your UI.

So now you can find the most appropriate place to call

SomeUserModel yourUser = yourUsersApi.fetchUser("someUsers")

to fetch your remote data.

Answer 2

I have just used retrofit for a couple of weeks and at first I found it hard to use in my application. I would like to share to you the easiest way to use retrofit in you application. And then later on if you already have a good grasp in retrofit you can enhance your codes(separating your ui from api and use callbacks) and maybe get some techniques from the post above.

In your app you have Login,Activity for list of task,and activity to view detailed task.

First thing is you need to add retrofit in your app and theres 2 ways, follow @artemis post above.

Retrofit uses interface as your API. So, create an interface class.

public interface MyApi{

/*LOGIN*/
@GET("/api_reciever/login") //your login function in your api
public void login(@Query("username") String username,@Query("password") String password,Callback<String> calback); //this is for your login, and you can used String as response or you can use a POJO, retrofit is very rubust to convert JSON to POJO

/*GET LIST*/
@GET("/api_reciever/getlist") //a function in your api to get all the list
public void getTaskList(@Query("user_uuid") String user_uuid,Callback<ArrayList<Task>> callback); //this is an example of response POJO - make sure your variable name is the same with your json tagging

/*GET LIST*/
@GET("/api_reciever/getlistdetails") //a function in your api to get all the list
public void getTaskDetail(@Query("task_uuid") String task_uuid,Callback<Task> callback);   //this is an example of response POJO - make sure your variable name is the same with your json tagging

}

Create another interface class to hold all your BASE ADDRESS of your api

public interface Constants{
   public String URL = "www.yoururl.com"
}

In your Login activity create a method to handle the retrofit

private void myLogin(String username,String password){

RestAdapter restAdapter = new RestAdapter.Builder()
    .setEndpoint(Constants.URL)  //call your base url
    .build();


MyApi mylogin = restAdapter.create(MyApi.class); //this is how retrofit create your api
mylogin.login(username,password,new Callback<String>() {
        @Override
        public void success(String s, Response response) {
            //process your response if login successfull you can call Intent and launch your main activity

        }

        @Override
        public void failure(RetrofitError retrofitError) {
            retrofitError.printStackTrace(); //to see if you have errors
        }
    });
}

In your MainActivityList

private void myList(String user_uuid){

RestAdapter restAdapter = new RestAdapter.Builder()
    .setEndpoint(Constants.URL)  //call your base url
    .build();


MyApi mytask = restAdapter.create(MyApi.class); //this is how retrofit create your api
mytask.getTaskDetail(user_uuid,new Callback<Task>>() {
        @Override
        public void success(ArrayList<Task> list, Response response) {
            //process your response if successful load the list in your listview adapter

        }

        @Override
        public void failure(RetrofitError retrofitError) {
            retrofitError.printStackTrace(); //to see if you have errors
        }
    });
}

In your Detailed List

private void myDetailed(String task_uuid){

RestAdapter restAdapter = new RestAdapter.Builder()
    .setEndpoint(Constants.URL)  //call your base url
    .build();


MyApi mytask = restAdapter.create(MyApi.class); //this is how retrofit create your api
mytask.getTaskList(task_uuid,new Callback<Task>() {
        @Override
        public void success(Task task, Response response) {
            //process your response if successful do what you want in your task

        }

        @Override
        public void failure(RetrofitError retrofitError) {
            retrofitError.printStackTrace(); //to see if you have errors
        }
    });
}

Hope this would help you though its really the simplest way to use retrofit.

Answer 3

Take a look at this , excellent blog on using Retrofit in conjunction with Otto, both libraries are from Square.

http://www.mdswanson.com/blog/2014/04/07/durable-android-rest-clients.html

The basic idea is that you will hold a reference to a "repository" object in your Application class. This object will have methods that "subscribe" to rest api event requests. When one is received it will make the proper Retrofit call, and then "post" the response, which can then be "subscribed" to by another component (such as the activity that made the request).

Once you have this all setup properly, accessing data via your rest api becomes very easy. For example, making are request for data would look something like this :

    mBus.post(new GetMicropostsRequest(mUserId));

and consuming the data would look something like this:

@Subscribe
public void onGetUserProfileResponse(GetUserProfileResponse event) {
    mView.setUserIcon("http://www.gravatar.com/avatar/" + event.getGravatar_id());
    mView.setUserName(event.getName());

}

It takes a little bit of upfront effort, but in the end it becomes "trivial" to access anything you need from our backend via Rest.

Answer 4

You may try saving references to your api inside your application class. Then you can get it's instance from any activity or fragment and get api from there. That sounds a little weird, but it may be a simple DI alternative. And if you will only store references in your app class, it won't be a kind of god object

UPD: http://square.github.io/retrofit/ - here is some documentation, it might be useful

Answer 5

Using RetroFit is very easy.

• Add dependecy in build.gradle.

      compile 'com.squareup.retrofit:retrofit:1.9.0'
  
      compile 'com.squareup.okhttp:okhttp:2.4.0' 
  

• Make an Interface for all http methods.

• Copy your json output and create pojo class to recieve json of your
  response, you can make pojo from JsonSchema2pojo site .

• make an adapter and call your method

  for complete demo try this tutorial Retrofit Android example

Answer 6

Firstly, putting everything in MainActivity would be bad practice and you would end up with a God object.

The documentation on the Retrofit site is fantastic, so I'm going to read your question on how to structure the project. I wrote a very small app for demonstration purposes. It loads cats from the cat API and should be fairly simple to follow what is happening.

It has an example of using JSON or XML for the parsing of data from the service. You can find it at https://github.com/codepath/android_guides/wiki/Consuming-APIs-with-Retrofit

Hopefully you can extrapolate why I have structured it the way I have. I'm happy to answer any questions you have in the comments and update the answer.

Answer 7

Checkout this app that demonstrates Retrofit integration to Google Tasks API.

https://github.com/sschendel/SyncManagerAndroid-DemoGoogleTasks

There are examples of Retrofit api (TaskApi) used within Activity AsyncTask in MainActivity, as well as examples of use within Sync Adapter in background service.

The strategy from the article posted in @nPn's answer is probably a more elegant solution, but you can at least look at another working example.

Answer 8

I find these tutorials AndroidHive , CodePath helpful

I will briefly describe what I have learned.

Step 1 : Add these three dependencies to build.gradle and Add Internet permission to Manifest

compile 'com.google.code.gson:gson:2.6.2' // for string to class conversion. Not Compulsory
compile 'com.squareup.retrofit2:retrofit:2.1.0'// compulsory
compile 'com.squareup.retrofit2:converter-gson:2.1.0' //for retrofit conversion

Add them in Manifest

<uses-permission android:name="android.permission.INTERNET" />

Step 2 Creae ApiClient and ApiInterface.

public class ApiClient {

    public static final String BASE_URL = "http://yourwebsite/services/";
    private static Retrofit retrofit = null;

    public static Retrofit getClient() {
        if (retrofit==null) {
            retrofit = new Retrofit.Builder()
                    .baseUrl(BASE_URL)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }
}

where ApiInterface.class

public interface ApiInterface {

    // getting same data in three different ways.
    @GET("GetCompanyDetailByID")
    Call<CompanyResponse> getDetailOfComapanies(@Query("CompanyID") int companyID);


    @GET("GetCompanyDetailByID")
    Call<ResponseBody> getRawDetailOfCompanies(@Query("CompanyID") int companyID);

    @GET("{pathToAdd}")
    Call<CompanyResponse> getDetailOfComapaniesWithPath(@Path("pathToAdd") String pathToAppend, @Query("CompanyID") int companyID);
}

And call this service like

ApiInterface apiService =
                ApiClient.getClient().create(ApiInterface.class);

        Call<CompanyResponse> companyResponseCall = apiService.getDetailOfComapanies(2);
        //Call<CompanyResponse> companyResponseCall = apiService.getDetailOfComapaniesWithPath("GetCompanyDetailByID",2);

        companyResponseCall.enqueue(new Callback<CompanyResponse>() {
            @Override
            public void onResponse(Call<CompanyResponse> call, Response<CompanyResponse> response) {
                CompanyResponse comapnyResponse = response.body();
                Boolean status  = comapnyResponse.getStatus();
            }

            @Override
            public void onFailure(Call<CompanyResponse> call, Throwable t) {
            }
        });

For Getting Raw Json String

Call<ResponseBody> call = apiService.getRawDetailOfCompanies(2);
        call.enqueue(new Callback<ResponseBody>() {
            @Override
            public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                    String jsonStr = response.body().string();
                    if(!jsonStr.isEmpty()){
                        Gson gson = new Gson();

                        JSONObject jObject = new JSONObject(jsonStr).getJSONObject("data");

                        //1st Method
                        Data dataKiType = gson.fromJson(jObject.toString(), Data.class);
                        dataKiType.getCompanyDetail();

                        //2nd method for creaing class or List at runTime
                        Type listType = new TypeToken<Data>(){}.getType();
                        Data yourClassList = new Gson().fromJson(jObject.toString(), listType);
                        yourClassList.getCompanyDetail();
                    }  e.printStackTrace();
                }
            }

            @Override
            public void onFailure(Call<ResponseBody> call, Throwable t) {
            }
        });

You can create your business object using http://www.jsonschema2pojo.org/ by simply pasting json. and selecting source type to JSON and Annotation Style to GSon

Answer 9

Found a small, but complete and concise example at https://github.com/square/retrofit/tree/master/samples

Answer 10

Beginners find it little intimidating to learn retrofit. I have prepared a tutorial which will simplify the learning curve. See Retrofit android tutorial for more information.

Answer 11

Developing your own type-safe HTTP library to interface with a REST API can be a real pain: you have to handle many aspects, such as making connections, caching, retrying failed requests, threading, response parsing, error handling, and more. Retrofit, on the other hand, is a well-planned, documented and tested library that will save you a lot of precious time and headaches.

compile 'com.google.code.gson:gson:2.6.2'

compile 'com.squareup.retrofit2:retrofit:2.1.0'// compulsory

compile 'com.squareup.retrofit2:converter-gson:2.1.0' //for retrofit conversion

Answer 12

First, add this lines to gradle file

compile 'com.squareup.retrofit2:retrofit:2.1.0'
    compile 'com.squareup.retrofit2:converter-gson:2.1.0'
    compile 'com.google.code.gson:gson:2.7'
    compile 'com.squareup:otto:1.3.8'
    compile 'com.squareup.okhttp3:logging-interceptor:3.4.1'

Then Create Objects in OnCreate of Activity

HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);    
OkHttpClient client= new OkHttpClient
                .Builder()
                .connectTimeout(30, TimeUnit.SECONDS)
                .readTimeout(30, TimeUnit.SECONDS)
                .addInterceptor(interceptor).build();
Gson gson=new GsonBuilder()
          .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
          .create();
Retrofit retrofit= new Retrofit.Builder()
                .baseUrl("url")
                .client(client)
                .addConverterFactory(GsonConverterFactory.create(gson))
                .build();

Create an iterface

public interface summaryListAPI {
//post
    @FormUrlEncoded
    @POST("index.php")
    Call<summaryList> post(
            @Field("status") String status,
            @Field("sox") String sox
    );
//get
@GET("yesbdeChatHistoryList/{userId}/")
    Call<List<ChatTabTwoResp>> getFriends(
            @Path("userId") int userId
    );
}

Create classes

public class summaryList {
    @SerializedName("bookingSummary") @Expose private List<summaryListData> status = new ArrayList<summaryListData>();
}   

public class summaryListData {
    @SerializedName("date") @Expose private String date;
}

Add this Method to your activity

 public void apiSummaryListMain(final Retrofit retrofit) {
        retrofit.create(summaryListAPI.class).post("8547861657","100").enqueue(new Callback<summaryList>() {
            @Override
            public void onResponse(Call<summaryList> call, Response<summaryList> response) {
                if (response.isSuccessful()) {
                    progressBar.setVisibility(View.INVISIBLE);
                     List<summaryListData> summary_List= response.body().getStatus();                   
                }else{              
                }
            }
            @Override
            public void onFailure(Call<summaryList> call, Throwable t) {

            }
        });

    }

Answer 13

Its Working

package com.keshav.gmailretrofitexampleworking.network;

import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class ApiClient {
    public static final String BASE_URL = "http://api.androidhive.info/json/";
    private static Retrofit retrofit = null;

    public static Retrofit getClient() {
        if (retrofit == null) {
            retrofit = new Retrofit.Builder()
                    .baseUrl(BASE_URL)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }
}
==============================================
package com.keshav.gmailretrofitexampleworking.network;

import com.keshav.gmailretrofitexampleworking.models.Message;

import java.util.List;

import retrofit2.Call;
import retrofit2.http.GET;

public interface ApiInterface {
    @GET("inbox.json")
    Call<List<Message>> getInbox();
}

compile 'com.google.code.gson:gson:2.6.2'

compile 'com.squareup.retrofit2:retrofit:2.0.2'

compile 'com.squareup.retrofit2:converter-gson:2.0.2'

=====================================================

Call Retrofit 2 APi inside onCreate

private void getInbox() {
    swipeRefreshLayout.setRefreshing(true);

    ApiInterface apiService =
            ApiClient.getClient().create(ApiInterface.class);

    Call<List<Message>> call = apiService.getInbox();
    call.enqueue(new Callback<List<Message>>() {
        @Override
        public void onResponse(Call<List<Message>> call, Response<List<Message>> response) {
            // clear the inbox
            messages.clear();

            // add all the messages
            // messages.addAll(response.body());

            // TODO - avoid looping
            // the loop was performed to add colors to each message

            Log.e("keshav","response" +response.body());

            for (Message message : response.body()) {
                // generate a random color

                // TODO keshav Generate Random Color Here
                message.setColor(getRandomMaterialColor("400"));
                messages.add(message);
            }

            mAdapter.notifyDataSetChanged();
            swipeRefreshLayout.setRefreshing(false);
        }

        @Override
        public void onFailure(Call<List<Message>> call, Throwable t) {
            Toast.makeText(getApplicationContext(), "Unable to fetch json: " + t.getMessage(), Toast.LENGTH_LONG).show();
            swipeRefreshLayout.setRefreshing(false);
        }
    });
}

Source Code https://drive.google.com/open?id=0BzBKpZ4nzNzUVFRnVVkzc0JabUU

https://drive.google.com/open?id=0BzBKpZ4nzNzUc2FBdW00WkRfWW8

Answer 14

I just braked this problem in a very easy way you just need install a plugin and follow some steps to implement retrofit in any of your App.:

Already posted answer : Retrofit in android?

Add (QAssist - Android Studio Plugin) Android plugin in your Android studio. ( https://github.com/sakkeerhussain/QAssist ).

Hope this will help you.

Answer 15

Simple retrofit + okhttp integration using RxJava

public WebService apiService(Context context) {
    String mBaseUrl = context.getString(BuildConfig.DEBUG ? R.string.local_url : R.string.live_url);

    int cacheSize = 5 * 1024 * 1024; // 5 MB
    Cache cache = new Cache(context.getCacheDir(), cacheSize);

    HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor();
    loggingInterceptor.setLevel(BuildConfig.DEBUG ? HttpLoggingInterceptor.Level.BODY : HttpLoggingInterceptor.Level.NONE);

    OkHttpClient okHttpClient = new OkHttpClient.Builder()
            .readTimeout(120, TimeUnit.SECONDS)
            .writeTimeout(120, TimeUnit.SECONDS)
            .connectTimeout(120, TimeUnit.SECONDS)
            .addInterceptor(loggingInterceptor)
            //.addNetworkInterceptor(networkInterceptor)
            .cache(cache)
            .build();

    return new Retrofit.Builder().baseUrl(mBaseUrl)
            .client(okHttpClient)
            .addConverterFactory(GsonConverterFactory.create())
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
            .build().create(WebService.class);

}

Answer 16

public interface APIService {

    @POST(Constant.updateProfile)
    @FormUrlEncoded
    Call<ResponseBody> updateProfile(
            @Field("user_id") String user_id,
            @Field("first_name") String first_name,
            @Field("last_name") String last_name
    );
}

public class RetrofitClient {
    private static Retrofit retrofit = null;

    public static Retrofit getClient(String baseUrl) {
        if (retrofit == null) {
            retrofit = new Retrofit.Builder()
                    .baseUrl(baseUrl)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }

}


public class Body {


// Check Status if Status True or False
String status;
String message;
String checksum;
  
}



public interface OnBodyResponseListner {


public void onSucces(Body response);
public void onFailure(Body response);
public void onBlankBody(Call<ResponseBody> call);

}

 public static void setOnWebServiceCallListner(final Call<ResponseBody> t, final OnBodyResponseListner onBodyResponseListner) {
    t.enqueue(new Callback<ResponseBody>() {
        @Override
        public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
            try {
                call.cancel();
                Gson gson = new GsonBuilder().serializeNulls().create();
                String json = response.body().string();
                Log.d(TAG, json + "  ~ Response ~  " + json);
                Body body = gson.fromJson(json, Body.class);

                if (body.getStatus().equalsIgnoreCase("true")) {
                    onBodyResponseListner.onSucces(body);
                } else {
                    onBodyResponseListner.onFailure(body);
                }


            } catch (Exception e) {
            }
        }

        @Override
        public void onFailure(Call<ResponseBody> call, Throwable t) {
            onBodyResponseListner.onBlankBody(call);
            Log.d(TAG, "~ Response Message Blank ~ " + t.getMessage() + " \n Localize Message ~ " + t.getLocalizedMessage() + " \n" + t.getStackTrace().toString());
        }
    });


}


 APIService mService = RetrofitClient.getClient(Constant.BASE_URL).create(APIService.class);


Oprations.setOnWebServiceCallListner(mService.updateProfile("12",
            "first_name",
            "last,name"
    ), new OnBodyResponseListner() {
        @Override
        public void onSucces(Body response) {
            
           

        }

        @Override
        public void onFailure(Body response) {
            
            Toast.makeText(mContext, response.getMessage(), Toast.LENGTH_SHORT).show();

        }

        @Override
        public void onBlankBody(Call<ResponseBody> call) {

        }
    });
}

Answer 17

1. First, add the dependency - compile 'com.squareup.retrofit:retrofit:1.7.1'
2. Create retrofit instance class

public class RetrofitClientInstance {
    private Context context;
    private static OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
    private static Retrofit retrofit
    private static Retrofit.Builder builder =
            new Retrofit.Builder()
                    .baseUrl(BuildConfig.SERVER_URL)
                    .client(getRequestHeader())
                    .addConverterFactory(GsonConverterFactory.create());
    public static HttpLoggingInterceptor setLogger() {
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);
        return logging;
    }
    public static <S> S createService(Class<S> serviceClass) {

        if (!httpClient.interceptors().isEmpty()) {

            httpClient.interceptors().clear();
        }
        httpClient.authenticator(new AccessTokenAuthenticator());
        httpClient.readTimeout(60,TimeUnit.SECONDS);
        httpClient.connectTimeout(60,TimeUnit.SECONDS);
        httpClient.addInterceptor(setLogger());
        httpClient.addInterceptor(new Interceptor() {
            @Override
            public Response intercept(Chain chain) throws IOException {
                Request original = chain.request();
                Request.Builder requestBuilder = original.newBuilder()
                        .header("LocalSystemDate", MyApplication.getInstance().getCurrentDateAndTimeWithTimeZone())
                        .addHeader("channel_id", AppConst.CHANNEL_ID)
                        .addHeader("Authorization", "Bearer" + " " + SharedPref.getsAccessToken())
                        .method(original.method(), original.body());
                Request request = requestBuilder.build();
                return chain.proceed(request);
            }
        });

        OkHttpClient client = httpClient.build();
        Retrofit retrofit = builder.client(client).build();
        return retrofit.create(serviceClass);
    }


    private static OkHttpClient getRequestHeader() {

        return new OkHttpClient.Builder()
                .readTimeout(60, TimeUnit.SECONDS)
                .connectTimeout(60, TimeUnit.SECONDS)
                .build();
    }
}

3. Write the interface

public interface GetDataService {

    @Headers("Content-Type: application/json")
    @POST("login")
    Call<LoginResponseModel> loginUser(
          @Body LoginBodyModel loginBodyModel
    );

}

4. Call the service

GetDataService service = RetrofitClientInstance.createService(GetDataService.class);

Call<LoginResponseModel> loginModelCall = service.loginUser(loginBodyModel);

loginModelCall.enqueue(new Callback<LoginResponseModel>() {
    @Override
    public void onResponse(Call<LoginResponseModel> call, Response<LoginResponseModel> response) {

    }

    @Override
    public void onFailure(Call<LoginResponseModel> call, Throwable t)  {

    }
});

Answer 18

You can do this with hilt

@Module
@InstallIn(SingletonComponent::class)
object RestClientModule {

    @Provides
    @Singleton
    internal fun provideApiService(
        @WeatherRetrofit retrofit: Retrofit
    ): ApiService = retrofit.create(ApiService::class.java)





    @Provides
    @WeatherRetrofit
    @Singleton
    internal fun provideHiCityRetrofit(
        okHttpClient: OkHttpClient,
        moshi: Moshi
    ): Retrofit = Retrofit.Builder()
        .baseUrl(EndPoint.STAGE_BASE_URL)
        .client(okHttpClient)
        .addConverterFactory(ScalarsConverterFactory.create())
        .addConverterFactory(MoshiConverterFactory.create(moshi))
        .build()
}

Answer 19

You can checkout this Github Link with source-code avaible for login and signup API in android. https://github.com/probelalkhan/kotlin-retrofit-tutorial/commits/master

Or you can check this tutorial for learning purpose. https://youtu.be/TyJEDhauUeQ

Or for more other details checkout this

https://gist.github.com/codinginflow/d7a02bd69eebf566b4650c41bc362be7