request_retry_access_token_refresh_token.kt

// Retrofit API interface
interface MyApiService {
    // Example API endpoint that requires an access token
    @GET("example_endpoint")
    suspend fun getExampleData(@Header("Authorization") authToken: String): Response<ExampleData>
}

// Retrofit API client
class MyApiClient(private val sharedPreferences: SharedPreferences) {
    private val apiService = Retrofit.Builder()
        .baseUrl("https://example.com/api/")
        .addConverterFactory(GsonConverterFactory.create())
        .build()
        .create(MyApiService::class.java)
    
    suspend fun getExampleData(): ExampleData? {
        // Get the access token from shared preferences
        val accessToken = sharedPreferences.getString("access_token", null)
        
        // Make the API request with the access token
        val response = apiService.getExampleData("Bearer $accessToken")
        
        // If the response is unauthorized (status code 401), request a new access token with the refresh token and retry the request
        if (response.code() == 401) {
            // Get the refresh token from shared preferences
            val refreshToken = sharedPreferences.getString("refresh_token", null)
            
            // Request a new access token with the refresh token
            val newAccessToken = requestNewAccessToken(refreshToken)
            
            // If a new access token was obtained, update it in shared preferences and retry the request
            if (newAccessToken != null) {
                sharedPreferences.edit().putString("access_token", newAccessToken).apply()
                return apiService.getExampleData("Bearer $newAccessToken").body()
            }
        }
        
        // Return the response body if the request was successful or if a new access token was obtained and the retry was successful
        return response.body()
    }
    
    private suspend fun requestNewAccessToken(refreshToken: String): String? {
        // Example API endpoint for requesting a new access token with a refresh token
        val response = apiService.refreshAccessToken(refreshToken)
        return if (response.isSuccessful) response.body()?.accessToken else null
    }
}

// Example usage
val myApiClient = MyApiClient(sharedPreferences)
val exampleData = myApiClient.getExampleData()
if (exampleData != null) {
    // Process example data
} else {
    // Handle error
}
This code assumes that you have implemented an API endpoint for requesting a new access token with a refresh token, and that the response contains both the new access token and the refresh token. You may need to modify the code to fit your specific implementation.