Unresolved reference : retrofit while creating retrofit instance

user_16924388 0
Viewed 820

I am working on an android app which request Mars photos ans use it to display it on screen. To make an request.And trying to use A public Api object that exposes the lazy-initialized Retrofit service. below is source code with error

import retrofit2.Retrofit
import retrofit2.converter.scalars.ScalarsConverterFactory
import retrofit2.http.GET

class MarsApiService {
    public val retrofit = Retrofit.Builder()
    .addConverterFactory(ScalarsConverterFactory.create())
    .baseUrl(Companion.BASE_URL)
    .build()
interface MarsApiService{
    @GET("photos")
    fun getPhotos(): String
}
object MarsApi {
    val retrofitService: MarsApiService by lazy { retrofit.create(MarsApiService::class.java) }
}



companion object {
    private const val BASE_URL = "https://android-kotlin-fun-mars-server.appspot.com"
}
}

17th line the code inside object MarsApi pops up errors Unresolved reference : retrofit. The call to create() function on a Retrofit object is expensive and the app needs only one instance of Retrofit API service. So, i exposed the service to the rest of the app using object declaration.

What I have tried:

The code is working if i bring code inside object MarsApi out but doing so may result in multiple instance of retrofit.

retrofit kotlin android-studio
3 Answers

code1

interface MarsApiService {
    @GET("photos")
   suspend fun getPhotos(): String

    companion object {
        private const val BASE_URL = "https://android-kotlin-fun-mars-server.appspot.com"
        val marsApiService: MarsApiService by lazy {
            Retrofit.Builder()
                .addConverterFactory(ScalarsConverterFactory.create())
                .baseUrl(BASE_URL)
                .build().create(MarsApiService::class.java)
        }
    }
}

code2

private const val BASE_URL = "https://android-kotlin-fun-mars-server.appspot.com/"

private val retrofit = Retrofit.Builder()
    .addConverterFactory(ScalarsConverterFactory.create())
    .baseUrl(BASE_URL)
    .build()

interface MarsApiService {

    @GET("photos")
    suspend fun getPhotos(): String
}

object MarsApi {
    val marsApiService: MarsApiService by lazy { retrofit.create(MarsApiService::class.java) }
}

run


fun main() = runBlocking {
    val rs = marsApiService.getPhotos()
    println(rs)
}

In your code, retrofit by lazy reference not resolved cause of retrofit is property of class, move the retrofit globally like using (Companion) object or like code2 (highest hierarchy?)

user_130503130

Hope this link

make you clear the difference between object and companion object and when to use them. Happy learning

user_142598620

It was the same problem that I had. I solved it just excluding the class MarsApiService I didn´t use companion object too.

The right code is below

import retrofit2.Retrofit
import retrofit2.converter.scalars.ScalarsConverterFactory
import retrofit2.http.GET

private const val BASE_URL = "https://android-kotlin-fun-mars-server.appspot.com"

public val retrofit = Retrofit.Builder()
    .addConverterFactory(ScalarsConverterFactory.create())
    .baseUrl(Companion.BASE_URL)
    .build()

interface MarsApiService{
    @GET("photos")
    fun getPhotos(): String
}

object MarsApi {
    val retrofitService: MarsApiService by lazy { 
        retrofit.create(MarsApiService::class.java) 
    }
}
user_162363010
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