Test Retrofit

gistfile1.txt

**Dependencias**

```gradle
   implementation 'androidx.lifecycle:lifecycle-extensions:2.1.0'

    //Kotlin Coroutines
    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.1.1'
    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.2'

    //gson
    implementation 'com.google.code.gson:gson:2.8.6'

    //retrofit
    implementation 'com.squareup.retrofit2:retrofit:2.6.1'
    implementation 'com.squareup.retrofit2:converter-gson:2.6.1'
```

## Modelos

TodoModel = modelo normal
TodoResponse = modelo usando para leer los datos json en retrofit

```kotlin
data class TodoModel(
    val id: Int = 0,
    val title: String = "",
    val completed: Boolean = false
)

data class TodoResponse(

    @SerializedName("userId") val userId: Int,
    @SerializedName("id") val id: Int,
    @SerializedName("title") val title: String,
    @SerializedName("completed") val completed: Boolean
)
```

## Otros

```kotlin
class AppException(val exceptin: Throwable?): Exception()
```

MainActivity.kt

class MainActivity : AppCompatActivity() {

    companion object {
        val TAG: String = MainActivity::class.java.simpleName
    }

    private val mViewModel: MyViewModel by lazy {
        ViewModelProviders.of(this).get(MyViewModel::class.java)
    }

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

        /* mViewModel.getFirstTodo().observe(this, Observer<TodoModel> {
             tv_display.text = it.toString()
         })*/

        /*mViewModel.getFirstTodo().observe(this, Observer<Resource<TodoModel>> { value ->
            value?.let {
                when (value.status) {
                    Resource.Status.LOADING -> {
                        Log.d(TAG, "Loading...." + value.data)
                        tv_display.setText(R.string.app_name)
                    }
                    Resource.Status.SUCCESS -> {
                        Log.d(TAG, "Success....")
                        Log.d(TAG, value.data.toString())
                        tv_display.text = value.data.toString()
                    }
                    Resource.Status.ERROR -> {
                        Log.d(TAG, "Error....")
                    }
                }
            }

        })
*/

        mViewModel.getAllTodos2().observe(this, Observer<Resource<List<TodoModel>>> { value ->
            value?.let {
                when (value.status) {
                    Resource.Status.LOADING -> {
                        Log.d(TAG, "Loading...." + value.data)
                        tv_display.setText(R.string.app_name)
                    }
                    Resource.Status.SUCCESS -> {
                        Log.d(TAG, "Success....")
                        Log.d(TAG, value.data.toString())
                        tv_display.text = value.data?.size.toString()
                    }
                    Resource.Status.ERROR -> {
                        Log.d(TAG, "Error....")
                    }
                }
            }

        })



        fab.setOnClickListener { view ->
            toast("Hello world!")
            //mViewModel.sayHelloWorld()
        }
    }

    fun Context.toast(message: CharSequence) =
        Toast.makeText(this, message, Toast.LENGTH_SHORT).show()

}

MyViewModel.kt

class MyViewModel : ViewModel() {

    private val viewModelJob = SupervisorJob()
    private val uiScope = CoroutineScope(Dispatchers.Default + viewModelJob)

    val respuesta: MutableLiveData<Resource<TodoModel>> = MutableLiveData()

    val respuesta2: MutableLiveData<Resource<List<TodoModel>>> = MutableLiveData()

    val repository: TodoRepository = TodoRepository(TodoApiServiceFactory.todobApi)

    //private val productDataMapper: Mapper<TodoResponse, TodoModel>

    fun getFirstTodo(): LiveData<Resource<TodoModel>> {
        return repository.getTodo(2)
    }

    fun getFirstTodo2(): LiveData<Resource<TodoModel>> {
        uiScope.launch(Dispatchers.IO) {
            val datos = repository.getTodo2(4)
            //respuesta.postValue(Resource.success(TodoModel(1,"prueba",true)))
            respuesta.postValue(datos)
        }
        return respuesta
    }

    fun getAllTodos(): LiveData<Resource<List<TodoModel>>> {
        return repository.getTodosList(2)
    }

    fun getAllTodos2(): LiveData<Resource<List<TodoModel>>> {
        uiScope.launch(Dispatchers.IO) {
            val datos = repository.getTodoList2()
            //respuesta.postValue(Resource.success(TodoModel(1,"prueba",true)))
            respuesta2.postValue(datos)
        }
        return respuesta2
    }



    override fun onCleared() {
        super.onCleared()
        uiScope.coroutineContext.cancelChildren()
    }
}

Resource.kt

class Resource<T> private constructor(
    val status: Status,
    val data: T?,
    val exception: AppException?
) {
    enum class Status {
        SUCCESS, ERROR, LOADING
    }

    companion object {
        fun <T> success(data: T?): Resource<T> {
            return Resource(
                Status.SUCCESS,
                data,
                null
            )
        }

        fun <T> error(exception: AppException?): Resource<T> {
            return Resource(
                Status.ERROR,
                null,
                exception
            )
        }

        fun <T> loading(data: T?): Resource<T> {
            return Resource(
                Status.LOADING,
                data,
                null
            )
        }
    }
}

TodoApiService.kt

interface TodoAPIService {

    @GET("/todos/{id}")
    fun getTodo(@Path("id") id: Int): Call<TodoResponse>

    @GET("/todos/{id}")
    suspend fun getTodo2(@Path("id") id: Int): TodoResponse

    @GET("/todos")
    fun getTodos(): Call<List<TodoResponse>>

    @GET("/todos")
    suspend fun getTodos2(): List<TodoResponse>

}

TodoApiServiceFactory.kt

/*
https://android.jlelse.eu/android-networking-in-2019-retrofit-with-kotlins-coroutines-aefe82c4d777
 */
object TodoApiServiceFactory {

    fun retrofit(): Retrofit = Retrofit.Builder()
        .baseUrl("https://jsonplaceholder.typicode.com/")
        .addConverterFactory(GsonConverterFactory.create())
        .build()

    val todobApi = retrofit()
        .create(TodoAPIService::class.java)

}

TodoRespository.kt

/*
https://proandroiddev.com/suspend-what-youre-doing-retrofit-has-now-coroutines-support-c65bd09ba067
https://proandroiddev.com/the-real-repository-pattern-in-android-efba8662b754
https://proandroiddev.com/demystifying-retrofit-network-call-with-kotlin-livedata-27437439137a
https://github.com/rifqimfahmi/android-mvvm-coroutine/blob/master/app/src/main/java/com/rifqimfahmi/foorballapps/data/source/SportRepository.kt
 */
class TodoRepository(private var todoApiService: TodoAPIService) {

    fun getTodo(id: Int): LiveData<Resource<TodoModel>> {
        val liveData = MutableLiveData<Resource<TodoModel>>()
        // Dispatchers.IO
        /* perform blocking network IO here */

        todoApiService.getTodo(id).enqueue(object : Callback<TodoResponse> {

            override fun onResponse(
                call: Call<TodoResponse>,
                response: Response<TodoResponse>
            ) {
                if (response.isSuccessful) {
                    liveData.value = Resource.success(
                        TodoModel(
                            response.body()!!.id,
                            response.body()!!.title,
                            response.body()!!.completed
                        )
                    )
                    // When data is available, populate LiveData
                    //liveData.value = response?.body()
                }
            }

            override fun onFailure(call: Call<TodoResponse>, t: Throwable) {
                t.printStackTrace()
                liveData.value = Resource.error(AppException(t.cause))
            }
        })
        // Synchronously return LiveData
        // Its value will be available onResponse
        return liveData

    }

    suspend fun getTodo2(id: Int): Resource<TodoModel> {

        // Dispatchers.IO
        /* perform blocking network IO here */
        return try {
            val datos = todoApiService.getTodo2(id)
            Resource.success(TodoModel(datos.id, datos.title, datos.completed))
        } catch (e: Exception) {
            println("Caught ArithmeticException")
            Resource.success(null)
        }
    }

    fun getTodosList(id: Int): LiveData<Resource<List<TodoModel>>> {

        val liveData = MutableLiveData<Resource<List<TodoModel>>>()
        // Dispatchers.IO
        /* perform blocking network IO here */

        todoApiService.getTodos().enqueue(object : Callback<List<TodoResponse>> {

            override fun onResponse(
                call: Call<List<TodoResponse>>,
                response: Response<List<TodoResponse>>
            ) {
                if (response.isSuccessful) {
                    Log.d(
                        "aaa", "size response" + response.body()?.size
                    )
                    val nameMap: List<TodoModel>? = response.body()?.map { TodoModel(it.id,it.title,it.completed) };
                    liveData.postValue(Resource.success(nameMap))
                }
            }

            override fun onFailure(call: Call<List<TodoResponse>>, t: Throwable) {
                t.printStackTrace()
                liveData.value = Resource.error(AppException(t.cause))
            }
        })
        // Synchronously return LiveData
        // Its value will be available onResponse


        return liveData

    }
    //val value = NetworkCall<TodoResponse>().makeCall(todoApiService.getTodo(id)).value?.data

    suspend fun getTodoList2(): Resource<List<TodoModel>> {

        // Dispatchers.IO
        /* perform blocking network IO here */
        return try {
            val datos = todoApiService.getTodos2()
            val nameMap: List<TodoModel>? = datos.map { TodoModel(it.id,it.title,it.completed) };

            Resource.success(nameMap)
        } catch (e: Exception) {
            println("Caught ArithmeticException")
            Resource.success(null)
        }
    }


    /*private lateinit var localDataSource: LocalDataSource
    private lateinit var remoteDataSource: RemoteDataSource

    operator fun invoke(context: Context): MyRepository {
        //...
        localDataSource = LocalDataSourceImpl.getInstance(context)
        remoteDataSource = RemoteDataSourceImpl.getInstance(context)
        return this
    }*/

}