don't know how to access data using retrofit

[Gioele]

I'm writing an application that have to get data from this site: https://api.spacex.land/graphql/.

I'm using retrofit for the first time and I don't have idea how I have to set the API service to get, for example, the launchLatest from this site.

This is my model:

data class LaunchModel(
var details: String,
var id: String,
var isTentative: Boolean,
var launchDateLocal: Date,
var launchDateUnix: Date,
var launchDateUtc: Date,
var launchSite: LaunchSiteModel,
var launchSuccess: Boolean,
var launchYear: String,
var links: LaunchLinksModel,
var missionId: String,
var missionName: String,
var rocket: LaunchRocketModel,
var staticFireDateUnix: Date,
var staticFireDateUtc: Date,
var telemetry: LaunchTelemetryModel,
var tentativeMaxPrecision: String,
var upComing: Boolean,
var ships : ShipModel,
)

this is the RetroIstance, a class that instance the settings of retrofit:

class RetroInstance {
companion object{
private const val baseUrl = "https://api.spacex.land/"

fun getRetroInstance() : Retrofit {

val client = OkHttpClient.Builder()
return Retrofit.Builder()
.baseUrl(baseUrl)
.addConverterFactory(GsonConverterFactory.create())
.client(client.build())
.build()
}
}
}

this is my main activity:

class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val retroInstance = RetroInstance.getRetroInstance().create(RetroService::class.java)
val retrofitData = retroInstance.getLastLaunch()
retrofitData.enqueue(object: Callback<LaunchModel> {
override fun onFailure(call: Call<LaunchModel>, t: Throwable) {
Toast.makeText(this@MainActivity, "call fail", Toast.LENGTH_LONG).show()
}

override fun onResponse(
call: Call<LaunchModel>,
response: Response<LaunchModel>
) {
val responseBody = response.body()

if(responseBody != null){
Toast.makeText(this@MainActivity, "${responseBody.id} + ${responseBody.details}", Toast.LENGTH_LONG).show()
}else {
Toast.makeText(this@MainActivity, "null calling! ${responseBody}", Toast.LENGTH_LONG).show()
}
}
})
}
}

and this is the interface where I try to set the method that get the launchLatest from the site:

interface RetroService {
@GET("graphql/")
fun getLastLaunch () : Call<LaunchModel>
}

I can't understand how to set this method to retrive the date from launchLatest. Can someone help me please? thanks

This is the output when a make the request from the browser:

{
"data": {
"launchLatest": {
"id": "109"
}
}
}

 

[Unforgiven]

Development thread moved to the dev area for better exposure.

 

[James_Watson]

It seems to be a web api call. You can test a web api with the famous utility, PostMan.

 

[saramarz]

To retrieve the launchLatest data from the SpaceX GraphQL API using Retrofit, you can update your Retrofit service interface as follows:

interface RetroService {
  @POST("graphql/")
  @Headers("Content-Type: application/json")
  fun getLastLaunch(): Call<LaunchModel>

  data class LaunchModel(val data: Data)

  data class Data(val launchLatest: LaunchLatest)

  data class LaunchLatest(
    val id: String,
    val details: String?,
    val isTentative: Boolean?,
    val launchDateLocal: String?,
    val launchDateUnix: Long?,
    val launchDateUtc: String?,
    val launchSite: LaunchSite?,
    val launchSuccess: Boolean?,
    val launchYear: String?,
    val links: Links?,
    val missionId: List<String>?,
    val missionName: String?,
    val rocket: Rocket?,
    val staticFireDateUnix: Long?,
    val staticFireDateUtc: String?,
    val telemetry: Telemetry?,
    val tentativeMaxPrecision: String?,
    val upcoming: Boolean?,
    val ships: List<Ship>?
  )

  data class LaunchSite(val siteId: String, val siteNameLong: String)

  data class Links(val flickrImages: List<String>, val missionPatch: String, val missionPatchSmall: String, val presskit: String, val redditCampaign: String, val redditLaunch: String, val redditRecovery: String, val redditMedia: String, val videoLink: String)

  data class Rocket(val rocketId: String, val rocketName: String, val rocketType: String)

  data class Telemetry(val flightClub: String)

  data class Ship(val shipId: String, val shipName: String, val shipModel: String)
}

To make the request, you can use the following code:

val retroInstance = RetroInstance.getRetroInstance().create(RetroService::class.java)
val requestBody = "{\"query\":\"{launchLatest{id, details, isTentative, launchDateLocal, launchDateUnix, launchDateUtc, launchSite{siteId, siteNameLong}, launchSuccess, launchYear, links{flickrImages, missionPatch, missionPatchSmall, presskit, redditCampaign, redditLaunch, redditRecovery, redditMedia, videoLink}, missionId, missionName, rocket{rocketId, rocketName, rocketType}, staticFireDateUnix, staticFireDateUtc, telemetry{flightClub}, tentativeMaxPrecision, upcoming, ships{shipId, shipName, shipModel}}}\",\"variables\":null}"
val retrofitData = retroInstance.getLastLaunch(requestBody)
retrofitData.enqueue(object: Callback<RetroService.LaunchModel> {
  override fun onFailure(call: Call<RetroService.LaunchModel>, t: Throwable) {
    Toast.makeText(this@MainActivity, "call fail", Toast.LENGTH_LONG).show()
  }

  override fun onResponse(
    call: Call<RetroService.LaunchModel>,
    response: Response<RetroService.LaunchModel>
  ) {
    val responseBody = response.body()

    if(responseBody != null){
      val