dcampogiani

class EitherViewModel : ViewModel() {

    private val mutableValidation: MutableLiveData<Either<String, Data>> = MutableLiveData()

    val validation: LiveData<Either<String, Data>>
        get() = mutableValidation


    fun validate(mail: String, phoneNumber: String) {
        mutableValidation.value = validateData(mail, phoneNumber)

dcampogiani

class EitherActivity : AppCompatActivity() {

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

        val viewModel = ViewModelProviders.of(this)[EitherViewModel::class.java]

        signup_button.setOnClickListener {
            viewModel.validate(email.text.toString(), number.text.toString())

dcampogiani

private fun handleLeft(error: String) {
        showMessage(error)
    }

dcampogiani

private fun handleRight(data: Data) {
        val message = "Mail: ${data.mail} Phone: ${data.phone}"
        showMessage(message)
    }

dcampogiani

sealed class ValidationError {
    object InvalidMail : ValidationError()
    object InvalidPhoneNumber : ValidationError()
}

dcampogiani

fun String.validatedMail(): Validated<Nel<ValidationError>, String> =
        when {
            validMail(this) -> this.valid()
            else -> ValidationError.InvalidMail.nel().invalid()
        }

fun String.validatedPhoneNumber(): Validated<Nel<ValidationError>, String> =
        when {
            validNumber(this) -> this.valid()
            else -> ValidationError.InvalidPhoneNumber.nel().invalid()

dcampogiani

class ValidatedNelValidationErrorViewModel : ViewModel() {

    private val mutableValidation: MutableLiveData<Validated<Nel<ValidationError>, Data>> = MutableLiveData()

    val validation: LiveData<Validated<Nel<ValidationError>, Data>>
        get() = mutableValidation


    fun validate(mail: String, phoneNumber: String) {
        mutableValidation.value = validateData(mail, phoneNumber)

dcampogiani

class ValidatedNelValidationErrorActivity : AppCompatActivity() {

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

        val viewModel = ViewModelProviders.of(this)[ValidatedNelValidationErrorViewModel::class.java]

        signup_button.setOnClickListener {
            viewModel.validate(email.text.toString(), number.text.toString())

dcampogiani

fun handleInvalid(errors: Nel<ValidationError>) {
        errors.map { handleInvalidField(it) }.all.forEach { it.second.error = it.first }
    }

fun handleInvalidField(validationError: ValidationError): Pair<String, TextInputLayout> =
    when (validationError) {
        ValidationError.InvalidMail -> Pair(getString(R.string.invalid_mail), emailWrapper)
        ValidationError.InvalidPhoneNumber -> Pair(getString(R.string.invalid_phone_number), numberWrapper)
    }

dcampogiani

private fun handleValid(data: Data) {
        val message = "Mail: ${data.mail} Phone: ${data.phone}"
        showMessage(message)
    }