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How to send PUT requests using Retrofit in Kotlin Android

How to send PUT requests using Retrofit in Kotlin Android.

Here is a step-by-step tutorial on how to send PUT requests using Retrofit in Kotlin Android.

Step 1: Set up Retrofit in your Android project​

To begin, you need to add the Retrofit library to your Android project. Open your app-level build.gradle file and add the following dependencies:

implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'

Step 2: Create a data class for the request body​

Create a data class that represents the data you want to send in the PUT request. This class will be converted to JSON by Retrofit. For example, let's create a User data class:

data class User(val id: Int, val name: String, val email: String)

Step 3: Create an interface for the API endpoints​

Create an interface that defines the API endpoints you want to call. Annotate each method with the HTTP method and the endpoint URL. For the PUT request, use the @PUT annotation. For example:

interface ApiService {
    @PUT("users/{id}")
    suspend fun updateUser(@Path("id") id: Int, @Body user: User): Response<User>
}

Step 4: Create a Retrofit instance​

Create an instance of the Retrofit class using the Retrofit.Builder. Pass the base URL of the API as a parameter. For example:

val retrofit = Retrofit.Builder()
    .baseUrl("https://api.example.com/")
    .addConverterFactory(GsonConverterFactory.create())
    .build()

val apiService = retrofit.create(ApiService::class.java)

Step 5: Send the PUT request​

To send a PUT request, call the corresponding method on the ApiService interface. Pass the required parameters, such as the user ID and the user object. Since the request is asynchronous, you can use Kotlin coroutines to handle the response. For example:

val userId = 1
val user = User(userId, "John Doe", "[email protected]")

GlobalScope.launch(Dispatchers.IO) {
    try {
        val response = apiService.updateUser(userId, user)
        if (response.isSuccessful) {
            val updatedUser = response.body()
            // Handle the updated user object
        } else {
            // Handle the error response
        }
    } catch (e: Exception) {
        // Handle the exception
    }
}

Note: Make sure to handle exceptions and error responses appropriately in your code.

That's it! You have successfully sent a PUT request using Retrofit in Kotlin Android. You can modify the data class and the API interface to match your specific use case. Retrofit provides many options for customizing requests, such as adding headers, query parameters, and more. Explore the Retrofit documentation for more information on advanced usage.