shiang / flutter-form-with-validation-bloc

This form and validation functions are created by using the BLOC pattern with RxDart instead of using StatefulWidget

BLOC Pattern Login Form

A login form with validation created with Flutter.

Getting Started

For help getting started with Flutter, view our online documentation.

About the app

• This form and validation functions are created by using the BLOC pattern with RxDart instead of using StatefulWidget

This app covers the following concepts from flutter, Dart and RxDart:

• BLOC pattern to share information/state in the app between different sections/screens
• Concept of Single Global Instance BLOC and Scoped Instance BLOC based on the scale of the app
• Single Global Instance: Single source of truth of your app state
• Scoped Instance: Multiple sources of truth divided based on sections/screens of the app
• StreamBuilder Widget to access streams/methods in the Bloc from another Widget
• Intro to RxDart for additional functionalities on Stream and StreamController
• Dart(Stream) => RxDart(Observable), Dart(StreamController) => RxDart(Subject)
• Using RxDart Observable to merge streams as one for form submission
• Concept of Single-Subscription Stream and Broadcast Stream
• Intro to BehaviorSubject to replace StreamController.broadcast for additional function to go back in time to retrieve the latest stream values for form submission
• Best practice on adding dispose function in Bloc class for the ability to close streams (or IDE might complain with warning)
• Best practice on setting StreamController as private instance method to avoid confusion from newcomers working on the same project

flutter-form-with-validation-bloc's Issues

How to use BLOC pattern to validate 'Confirm Password' text field?

I am using a Stream/Observable to validate 'Password' text field like final _emailController = BehaviorSubject(); Stream get email => _emailController.stream.transform(validateEmail); where valdiateEmail is a StreamTransformer<String,String> to validate whether the password length is at least 6. I am trying to use the similar idea for 'Confirm Password' but the validate function would take two inputs: password, confirmPassword; not sure how to handle this using StreamTransformer.

How to show validation on submit?

How to show validation on submit?

submit() {
    final validEmail = _emailController.value;
    final validPassword = _passwordController.value;

    print('Email is $validEmail, and password is $validPassword');
  }