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Launch Apollo Studio

4. Execute your first query

To execute your first query, you need to create an instance of ApolloClient and make a new call with your query.

Create an ApolloClient

Create a new file named Apollo.kt in the com.example.rocketreserver package and create an instance of ApolloClient in it:

app/src/main/java/com/example/rocketreserver/Apollo.kt
val apolloClient = ApolloClient.builder()
    .serverUrl("https://apollo-fullstack-tutorial.herokuapp.com")
    .build()

Note: apolloClient is a top-level variable so that it can be reused from other parts of the app later on for better performance. Reusing the apolloClient allows to reuse the underlying OkHttp instance and the associated threadpools and connections.

Creating the ApolloClient is as simple as giving it the endpoint of your GraphQL backend. It is https://apollo-fullstack-tutorial.herokuapp.com in our case.

Execute the query

Open LaunchListFragment.kt, override onViewCreated and launch a new coroutine. Use the apolloClient and the generated LaunchListQuery to execute a new query:

app/src/main/java/com/example/rocketreserver/LaunchListFragment.kt
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        lifecycleScope.launchWhenResumed {
            val response = apolloClient.query(LaunchListQuery()).await()

            Log.d("LaunchList", "Success ${response?.data}")
        }
    }

Thanks to Kotlin coroutines, the query will be executed in a background thread even if the code looks synchronous.

Test your query

Hit run. You should see this in the logcat output:

(logcat)
2020-05-25 19:36:12.211 1835-1956/com.example.rocketreserver D/LaunchList: Success Data(launches=Launches(__typename=LaunchConnection, cursor=1547220660, hasMore=true, launches=[Launch(__typename=Launch, id=93, site=KSC LC 39A), Launch(__typename=Launch, id=92, site=KSC LC 39A), Launch(__typename=Launch, id=91, site=CCAFS SLC 40), Launch(__typename=Launch, id=90, site=CCAFS SLC 40), Launch(__typename=Launch, id=89, site=CCAFS SLC 40), Launch(__typename=Launch, id=88, site=KSC LC 39A), Launch(__typename=Launch, id=87, site=CCAFS SLC 40), Launch(__typename=Launch, id=86, site=CCAFS SLC 40), Launch(__typename=Launch, id=85, site=CCAFS SLC 40), Launch(__typename=Launch, id=84, site=CCAFS SLC 40), Launch(__typename=Launch, id=83, site=CCAFS SLC 40), Launch(__typename=Launch, id=82, site=CCAFS SLC 40), Launch(__typename=Launch, id=81, site=KSC LC 39A), Launch(__typename=Launch, id=80, site=VAFB SLC 4E), Launch(__typename=Launch, id=79, site=CCAFS SLC 40), Launch(__typename=Launch, id=78, site=CCAFS SLC 40), Launch(__typename=Launch, id=77, site=KSC LC 39A), Launch(__typename=Launch, id=76, site=KSC LC 39A), Launch(__typename=Launch, id=75, site=CCAFS SLC 40), Launch(__typename=Launch, id=74, site=VAFB SLC 4E)]))

This means the request was correctly executed and you now have a list of launch sites 🚀🚀🚀.

Next, let's connect this data to your UI.

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