How to send parameters for get request using retrofit and kotlin Coroutines.?

Question

I was following the tutorial from https://proandroiddev.com/suspend-what-youre-doing-retrofit-has-now-coroutines-support-c65bd09ba067. I am having difficulty to understand how to send parameters to get request from MainActivity

Webservice.kt

interface Webservice {
@GET("/todos/{id}")
suspend fun getTodo(@Path(value = "id") todoId: Int): Todo
}

TodoRepository.kt

class TodoRepository {
var client: Webservice = RetrofitClient.webservice
suspend fun getTodo(id: Int) = client.getTodo(id)
}

MainViewModel.kt

class MainViewModel : ViewModel() {
val repository: TodoRepository = TodoRepository()

val firstTodo = liveData(Dispatchers.IO) {
    val retrivedTodo = repository.getTodo(1)

    emit(retrivedTodo)
    }
}

MainAcitvity.kt

class MainActivity : AppCompatActivity() {

lateinit var viewModel: MainViewModel

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    viewModel = ViewModelProviders.of(this).get(MainViewModel::class.java)

    showFirstTodo()
}

private fun showFirstTodo() {
    viewModel.getFirstTodo().observe(this, Observer {
        titleTextView.text = it.title
    })
}
}

Answer 1

You can change your viewModel code something like this

 private val _todo = MutableLiveData<Todo>()
 val todo : LiveData<Todo> get() =_todo

 //Call this method from activity
 fun getTodo(arg : Int)
 {
  val result = //Call Coroutines here
  _todo.postValue(result)
 }

Answer 2

There is a difference between Path and Query in GET request.
You can easily pass query string like this:

interface Webservice {

    @GET("/todos/{id}")
    suspend fun getTodo(@Path(value = "id") todoId: Int, @Query("name") name: String?): Todo
    }