Make use of rxdart

Author: EQuimper

Courses/Dart And Flutter The Complete Developers Guide/login_bloc/lib/src/app.dart

@@ -1,14 +1,17 @@
 import 'package:flutter/material.dart';
-import './screens/login_screen.dart';
+import 'package:login_bloc/src/blocs/provider.dart';
+import 'package:login_bloc/src/screens/login_screen.dart';
 
 class App extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
-    return MaterialApp(
-      title: 'Log me In',
-      home: Scaffold(
-        body: LoginScreen(),
-      )
+    return Provider(
+      child: MaterialApp(
+        title: 'Log me In',
+        home: Scaffold(
+          body: LoginScreen(),
+        ),
+      ),
     );
   }
-}
+}

Courses/Dart And Flutter The Complete Developers Guide/login_bloc/lib/src/blocs/bloc.dart

@@ -1,28 +1,38 @@
 import 'dart:async';
 
+import 'package:rxdart/rxdart.dart';
+
 import 'validators.dart';
 
 class Bloc with Validators {
-  final _emailController = StreamController<String>();
+  final _emailController = BehaviorSubject<String>();
 
-  final _passwordController = StreamController<String>();
+  final _passwordController = BehaviorSubject<String>();
 
   // Add data to stream
   Stream<String> get email => _emailController.stream.transform(validateEmail);
-  
+
   Stream<String> get password =>
       _passwordController.stream.transform(validatePassword);
 
+  Stream<bool> get isValid =>
+      Observable.combineLatest2(email, password, (e, p) => true);
+
   // Change data
   Function(String) get changeEmail => _emailController.sink.add;
 
   Function(String) get changePassword => _passwordController.sink.add;
 
+  submit() {
+    final validEmail = _emailController.value;
+    final validPassword = _passwordController.value;
+
+    print('Email is $validEmail and password is $validPassword');
+  }
+
   // Clean up
   dispose() {
     _emailController.close();
     _passwordController.close();
   }
 }
-
-final bloc = Bloc();

Courses/Dart And Flutter The Complete Developers Guide/login_bloc/lib/src/blocs/provider.dart

@@ -0,0 +1,17 @@
+import 'package:flutter/material.dart';
+import 'package:login_bloc/src/blocs/bloc.dart';
+
+class Provider extends InheritedWidget {
+  final bloc = new Bloc();
+
+  Provider({Key key, Widget child}) : super(key: key, child: child);
+
+  @override
+  bool updateShouldNotify(InheritedWidget oldWidget) {
+    return true;
+  }
+
+  static Bloc of(BuildContext context) {
+    return (context.inheritFromWidgetOfExactType(Provider) as Provider).bloc;
+  }
+}

Courses/Dart And Flutter The Complete Developers Guide/login_bloc/lib/src/screens/login_screen.dart

@@ -1,25 +1,28 @@
 import 'package:flutter/material.dart';
 import 'package:login_bloc/src/blocs/bloc.dart';
+import 'package:login_bloc/src/blocs/provider.dart';
 
 class LoginScreen extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
+    final bloc = Provider.of(context);
+
     return Container(
       margin: EdgeInsets.all(20.0),
       child: Column(
         children: <Widget>[
-          emailField(),
-          passwordField(),
+          emailField(bloc),
+          passwordField(bloc),
           Container(
             margin: EdgeInsets.only(top: 25.0),
           ),
-          submitButton(),
+          submitButton(bloc),
         ],
       ),
     );
   }
 
-  Widget emailField() {
+  Widget emailField(Bloc bloc) {
     return StreamBuilder<Object>(
       stream: bloc.email,
       builder: (context, snapshot) {
@@ -36,7 +39,7 @@ class LoginScreen extends StatelessWidget {
     );
   }
 
-  Widget passwordField() {
+  Widget passwordField(Bloc bloc) {
     return StreamBuilder<Object>(
       stream: bloc.password,
       builder: (context, snapshot) {
@@ -53,11 +56,15 @@ class LoginScreen extends StatelessWidget {
     );
   }
 
-  Widget submitButton() {
-    return RaisedButton(
-      child: Text('Login'),
-      color: Colors.blue,
-      onPressed: () {},
+  Widget submitButton(Bloc bloc) {
+    return StreamBuilder<Object>(
+      stream: bloc.isValid,
+      builder: (context, snapshot) {
+        return RaisedButton(
+            child: Text('Login'),
+            color: Colors.blue,
+            onPressed: snapshot.hasData ? bloc.submit : null);
+      },
     );
   }
 }

Courses/Dart And Flutter The Complete Developers Guide/login_bloc/pubspec.lock

@@ -81,6 +81,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.1"
+  rxdart:
+    dependency: "direct main"
+    description:
+      name: rxdart
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.21.0"
   sky_engine:
     dependency: transitive
     description: flutter

Courses/Dart And Flutter The Complete Developers Guide/login_bloc/pubspec.yaml

@@ -24,6 +24,8 @@ dependencies:
   # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^0.1.2
 
+  rxdart: ^0.21.0
+
 dev_dependencies:
   flutter_test:
     sdk: flutter