Retrofit Integration in Android - Kotlin

-
Retrofit is a Networking library, which is faster to use and easier to develop.

 Let’s see how to integrate Retrofit in Android with Kotlin.

 If you'd like to integrate RxJava as well, you can check here.

1. Configure:

  • Include the following in app-level build.gradle.

build.gradle
compile "com.squareup.retrofit2:retrofit:2.3.0"
compile "com.squareup.retrofit2:converter-gson:2.3.0"
  • Include internet permission in Manifest file.

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

2. Preparing Helper classes:

ApiInterface.kt
interface ApiInterface {
   @POST("get_users_detail") // Your url
   fun getUser(@Body requestBody: RequestBody): Call<UserResponse>
}

Model classes:

                     Response from Retrofit will be stored in POJO classes directly.

UserResponse.kt
data class UserResponse(var httpCode: String, var user: ArrayList<User>)

User.kt
data class User(val name: String, val phone: String)

3. Code

                           Here, the request parameters will be sent to api in the type of RequestBody, but you can send in any type as you wish. And GsonConverterFactory will convert the response as UserResponse pojo, that we can read.

RetrofitDemo.kt
class RetrofitDemo : AppCompatActivity() {
   private var list: ArrayList<User?> = ArrayList<User?>()
   lateinit var adapter: RecyclerAdapter
   lateinit var retrofit : Retrofit
   var url : String = "xxxxxxxxxx" // Your Base Url Ex: htttp://xxexample.com/api/
   lateinit var apiService : ApiInterface
   override fun onCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) {
       super.onCreate(savedInstanceState, persistentState)
       setContentView(R.layout.recycler)

       retrofit = Retrofit.Builder()
               .baseUrl(url)
               .addConverterFactory(GsonConverterFactory.create())
               .build()
       recyclerView.layoutManager = LinearLayoutManager(this, LinearLayout.VERTICAL, false)
       adapter = RecyclerAdapter(this, list);
       recyclerView.adapter = adapter
       callApi()
   }
   private fun callApi() {
       val json = JSONObject()
       json.put("id","20")
       val requestBody : RequestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), json.toString())
       apiService = retrofit.create(ApiInterface::class.java)
       val call : Call<UserResponse> = apiService.getUser(requestBody)
       call.enqueue(object : Callback<UserResponse> {
           override fun onFailure(call: Call<UserResponse>?, t: Throwable?) {
               Toast.makeText(this@RetrofitDemo, t!!.message,Toast.LENGTH_SHORT).show()
           }
           override fun onResponse(call: Call<UserResponse>?, response: Response<UserResponse>?) {
               val data : UserResponse? = response!!.body()
               if(data!!.httpCode.equals("200")) {
                   list.addAll(data.user);
                   adapter.notifyDataSetChanged()
               }else{
                   Toast.makeText(this@RetrofitDemo, getString(R.string.something_wrong),Toast.LENGTH_SHORT).show()
               }
           }
       });
   }
   class RecyclerAdapter(val context: Context, val data: ArrayList<User?>) : RecyclerView.Adapter<RecyclerAdapter.ViewHolder>() {
       override fun onBindViewHolder(holder: ViewHolder?, position: Int) {
           if (holder != null)
               holder.bindItems(data.get(position))
       }
       override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): ViewHolder {
           val v = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false)
           return ViewHolder(v)
       }
       override fun getItemCount(): Int {
           return data.size
       }
       class ViewHolder(itemView: View?) : RecyclerView.ViewHolder(itemView) {
           fun bindItems(map: User?) {
               itemView.itemid.text = map!!.name
               itemView.name.text = map.phone
           }
       }
   }
}

4. Run Application:

Finally run the application.

retrofit.png

Comments

Post a Comment

Popular posts from this blog

SOAP Client using ksoap2 in Android - Kotlin

-
Image
Introduction: SOAP stands for Simple Object Access Protocol. It is XML-based protocol that allows programs that run on different operating systems (like Windows, Linux, etc) to communicate using HTTP and XML. Pros: Security - SOAP provides its own security known as WS Security . Platform Independent - SOAP web services can be written in any programming language and executed in any platform Cons: Slow - It uses XML format that must be parsed, to be read. It defines many standards to be followed while developing. So its slow and consumes more bandwidth and resource. WSDL dependent - It uses WSDL mechanism and doesn't have any other mechanism to discover the service. Things to know: The following are the things we have to know before we proceed further:                     URL - It is the URL of WSDL file.                     NAMESPACE - It is ta...
Read more

Using Camera in Android - Kotlin

-
Image
Nowadays, most of our Android app require access to Camera to capture picture or Video. We can do that in two ways.                                 (i) Using built-in Camera,                                 (ii) Using custom Camera. Using Built-in Camera In this post, Let's see how to use the built-in camera to capture images and save it. Its a simple way to capture pics. We can use the mobile's built-in camera app using Intent.  val REQUEST_IMAGE_CAPTURE = 1 private fun takePictureIntent() { val takePictureIntent = Intent(MediaStore . ACTION_IMAGE_CAPTURE) if (takePictureIntent . resolveActivity(packageManager) != null) { startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE) } } After the picture has been captured, the result will received on on...
Read more

Room with LiveData, ViewModel - Android Architecture Components - Kotlin

-
Image
Introduction: We have already learnt about Room in last post,  Room-Kotlin . In this post, lets learn about how to use ViewModel and LiveData with Room to improve usablity. Using LiveData with Room, allows views to be notified about data changes automatically. LiveData: LiveData is nothing but observable data holder class. It allows us to observer changes in data across multiple components of app. It is also aware of and respects lifecycle of Activities/Fragments. It also ensures that LiveData only updates app component observers that are in an active lifecycle state. The following image depicts the Lifecycle and States: Here, CREATED, STARTED, RESUMED - Active States           INTIALIZED, DESTROYED - InActive States So, LiveData will remove the updates automatically while in InActive States, i.e., INTIALIZED and DESTROYED. ViewModel: ViewModel is an entity that is free of Activity/Fragment's lifecycle. So it allows us...
Read more

Map, Location update and AutoComplete Places - Kotlin

-
Image
Let's see how to show current location in Maps and also show the location which is chosen from AutoComplete in Maps with the updated Google play services. That is, for location listening we gonna use   FusedLocationProviderClient and for autocomplete places, we gonna use, GeoDataClient with AutoCompletePrediction, i.e., no need to call places url from our end, Google Playservices will do that work for you. Okiee, Let's start now. You can find the project in Github . PreRequisite: Navigate to  https://developers.google.com/maps/documentation/android-api/signup and do as per the instructions to start. Manifest: Include your API key, which you got from previous step in AndroidManifest.xml <meta-data android:name= "com.google.android.geo.API_KEY" android:value= "AIzXXXXXXXXXX_XXXXXXXXXXXXXX" /> Gradle: Include the following in app-level build 's dependencies. implementation 'com...
Read more

RecyclerView with different number of columns using SpanSizeLookup

-
Image
We already know how to design RecyclerView. But how to create RecyclerView with different columns depending on its row? Like below image? Yeah, we can do that, by using two different layouts with different viewType on Adapter. Another way is do some logic to do so. But, it's cumbersome. Luckily, we have another simple way to do that using SpanSizeLookUp . Let's see how to implement that in this post. Implementation: build.gradle Include the following in app-level gradle file. implementation 'com.android.support:recyclerview-v7:27.0.2' implementation 'com.android.support.constraint:constraint-layout:1.1.0-beta5' recycler.xml <?xml version= "1.0" encoding= "utf-8" ?> <android.support.constraint.ConstraintLayout xmlns:android= "http://schemas.android.com/apk/res/android" android:layout_width= "match_parent" android:layout_height= "match_parent" xmlns:ap...
Read more

Exploring Android Navigation Architecture Component - MVVM - Kotlin

-
Image
Navigation Architecture Component is released as a part of JetPack and androidx package. Its aim is to simplify the implementation of Navigation in our Android App. It defines a set of principles to build an in-app navigation with consistent and predictable user experience. Its main concept is to use single-activity architecture. It also has support for both Activity and Fragment. Principle of Navigation: The following are the principles of Navigation. App should have fixed starting destination A stack is used to represent the navigation state of app The 'Up' button never exits the app Up and Back are equivalent within your app's task Deep linking to a destination or navigating to the same destination should yield the same stack You can find the detailed explanation, here . Components of Navigation: (i) Navigation Graph - It's nothing but a map/blueprint of our in-app navigation. It has a list of all fragments and activities. We can also ...
Read more

Exploring Android Slices - JetPack

-
Image
Introduction: Slices are a new way of embedding our app's content in other surfaces, like Google Search and later in other places like Google Assistant. Slices are UI templates, which gives look and feel at home in whatever surface, they get hosts in. Also they are rich, interactive and dynamically updatable. Before jumping into that, first migrate your project to AndroidX, (Android Studio 3.2 & above), by navigating as,                                         Refactor --> Migrate  to AndroidX  Setup: build.gradle implementation 'androidx.slice:slice-core:1.0.0' implementation 'androidx.slice:slice-builders-ktx:1.0.0-alpha6' implementation 'androidx.slice:slice-builders:1.0.0' Creating Slice Provider: Slice Provider is a component that let us display the slices we are creating, on outside our application. We can create the Slice Pro...
Read more

FCM Integration in Android - Kotlin

-
Image
                                               Firebase Cloud Messaging inherits GCM’s core infrastructure but simplifies the client development. It works for all platforms (Android, IOS and Web). Let's see how to integrate FCM in Android with Kotlin. FCM Messages:         Two types of FCM messages are there.      Notification messages,  which are handled by the FCM SDK automatically.      Data messages, which are handled by the client app. It can have custom fields, which have to be sent by our server. 1. Configure FCM in Firebase Console (a) Go to https://console.firebase.google.com/ (b) Then click Add Project , a...
Read more

Stripe Integration in Android - Kotlin

-
Image
Stripe is one of the simplest payment gateway to be used. It enables us to process payments in minutes. Let's see how to integrate Stripe in Android using Kotlin. Operational Flow:             1. App should provide order details to Stripe server and the order total will be returned to App.             2. Then the user will enter the payment/card details. That will be sent to Stripe server and the result of the request will be sent back to the App. Create Stripe Account: (a) Go to  https://dashboard.stripe.com/register and enter all your details and create account.   (b) Click API in side tab. Make sure that the Account is in Test mode. And make a note of          Publishable Key and Secret Key for use. Code: build.gradle:   compile 'com.stripe:stripe-android:5.1.0' Layout files: main_layout.xml: <?xml version="1.0" encoding...
Read more