Retrofit

Dependencies

implementation("com.squareup.retrofit2:retrofit:2.11.0")
implementation("com.squareup.retrofit2:converter-gson:2.9.0")

Example data class

data class Music(
    val title: String,
    val url: String
)

Create interface for API actions

interface Api {
    @GET("/music")
    suspend fun getMusic(): List<Music>
}

Create Retrofit Instance

object RetrofitInstance {
    val api: Api by lazy {
        Retrofit.Builder()
            .baseUrl("https://skills-music-api.eliaschen.dev") // Example host
            .addConverterFactory(GsonConverterFactory.create())
            .build()
            .create(Api::class.java)
    }
}

ViewModel to retrieve data

class MainViewModel : ViewModel() {
    private val _musicList = MutableStateFlow<List<Music>>(emptyList())
    val musicList: StateFlow<List<Music>> get() = _musicList
    // handle error
    private val _failed = MutableStateFlow(false)
    val failed: StateFlow<Boolean> get() = _failed

    init {
        fetchMusicList()
    }

    private fun fetchMusicList() {
        viewModelScope.launch {
            try {
                val musicList = RetrofitInstance.api.getMusic()
                _musicList.value = musicList
            } catch (e: Exception) {
                _failed.value = true
            }
        }
    }
}

Retrieve data in composable

@Composable
fun MusicListScreen(viewModel: MainViewModel = viewModel()) {
    val musicList by viewModel.musicList.collectAsState()
    val failed by viewModel.failed.collectAsState()
    if (!failed) {
        LazyColumn {
            items(musicList) { music ->
                Column {
                    Text(text = music.title)
                    Text(text = music.url)
                }
            }
        }
    } else {
        Text("Failed Request!!!")
    }
}