/RxViewModel-Simple-Example

Primary LanguageKotlin

RxViewModel Simple Example - Login (Android)

This is an simple Android app using RxViewModel. RxViewModel is a library that making MVVM implementation easier.

The requirements are

  • User needs to enter username and password to login
  • The minimum length of username is 3
  • The minimum length of password is 5
  • If login button is disabled if the username or password is invalid
  • Show a "Login Successful" toast if username is admin and password is admin
  • Show a "Login Failed" toast if username is not admin or password is not admin
  • Show a "Login Error" toast if there is an unexpected exception happens.
  • The app produces an unexpected exception when the username is error and password is error

Clean Code - View layer

The view (LoginActivity) is super clean. It only does two things.

  • Render the Live Data (coming from RxJava Observable) in the ViewModel
  • Tell ViewModel to execute actions

No logic in the View

Clean code - ViewModel

The main idea of the RxViewModel is Action, State and ViewModel.

  • We have three Actions in this simple app. They are SetUsername, SetPassword and Login.
  • The State represent the data of the ViewModel.
  • The LoginViewModel is the core. It generate a next State based on action and current state. ViewModel also reveals the LiveData for View to render. And those LiveData are coming form the RxJava observables that RxViewMode provides.

The RxJava observables that RxViewModel provides

  • stateObservable
  • actionOnCompleteObservable
  • actionOnNextObservable
  • isLoadingObservable
  • errorObservable
  • actionErrorObservable

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