Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
This is an example of Android development with MVP + Interactor in Kotlin
interface LoginContracts {
interface View {
fun presentHomeScreen(user: User)
fun showError(message: String)
}
interface Presenter {
fun onDestroy()
fun onLoginButtonPressed(username: String, password: String)
}
interface Interactor {
fun unregister()
fun login(username: String, password: String)
}
interface InteractorOutput {
fun onLoginSuccess(user: User)
fun onLoginError(message: String)
}
}
class LoginActivity: BaseActivity, LoginContracts.View {
var presenter: LoginContracts.Presenter? = null
//other fields
override fun onCreate() {
//...
presenter = LoginPresenter(this)
loginButton.setOnClickListener { onLoginButtonClicked() }
//...
}
override fun onDestroy() {
presenter?.onDestroy()
presenter = null
super.onDestroy()
}
private fun onLoginButtonClicked() {
presenter?.onLoginButtonClicked(usernameEditText.text, passwordEditText.text)
}
fun presentHomeScreen(user: User) {
val intent = Intent(view, HomeActivity::class.java)
intent.putExtra(Constants.IntentExtras.USER, user)
startActivity(intent)
}
fun showError(message: String) {
//shows the error on a dialog
}
}
class LoginPresenter(var view: LoginContract.View?): LoginContract.Presenter, LoginContract.InteractorOutput {
var interactor: LoginContract.Interactor? = LoginInteractor(this)
fun onDestroy() {
view = null
interactor?.unregister()
interactor = null
}
fun onLoginButtonPressed(username: String, password: String) {
interactor?.login(username, password)
}
fun onLoginSuccess(user: User) {
view?.presentNextScreen(user)
}
fun onLoginError(message: String) {
view?.showError(message)
}
}
class LoginInteractor(var output: LoginContract.InteractorOutput?): LoginContract.Interactor {
fun unregister() {
output = null
}
fun login(username: String, password: String) {
LoginApiManager.login(username, password)
?.subscribeOn(Schedulers.newThread())
?.observeOn(AndroidSchedulers.mainThread())
?.subscribe({ user ->
//does something with the user, like saving it or the token
output?.onLoginSuccess(user)
},
{ throwable -> output?.onLoginError(throwable.message ?: "Error!") })
}
}
@diegovillacis10

This comment has been minimized.

Copy link

commented Dec 8, 2017

Great example! Thank you very much for this. Just a little fix will be that the LoginPresenter has the function fun onLoginButtonPressed(username: String, password: String) but is called in the LoginActivity as presenter?.onLoginButtonClicked(usernameEditText.text, passwordEditText.text)
Again, awesome example!

@shubham171294

This comment has been minimized.

Copy link

commented Mar 18, 2018

Nice example !!!
I want to ask a question. How will you show the login success in the activity? I mean when the login API call is successful, how do you notify the user about it? Will you create an interface and implement that in the LoginActivity?

@shoaibmushtaq25

This comment has been minimized.

Copy link

commented Sep 7, 2018

@shubham171294
in Interactor class, on output?.onLoginSuccess(user) will execute. and this onLoginSuccess(user) is implemented in LoginPresenter class as fun onLoginSuccess(user: User) { view?.presentNextScreen(user) } and now here in LoginPresenter, view?.presentNextScreen(user) would be called and it's implemented in LoginActivity as fun presentHomeScreen(user: User) { val intent = Intent(view, HomeActivity::class.java) intent.putExtra(Constants.IntentExtras.USER, user) startActivity(intent) } and user will navigate from LoginActivity to HomeActivity so that's the way how callbacks would work...

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.