Flutter

Flutter: How we're building a UI framework for tomorrow at Google" by Eric Seidel

Flutter is Google’s UI toolkit for building beautiful, natively compiled applications for mobile, web, and desktop from a single codebase.

https://api.flutter.dev/

https://flutter.dev/docs/resources/technical-overview

https://flutter.dev/docs/reference/tutorials

https://flutter.dev/
 flutter precache

 flutter doctor

Open plugin preferences (Preferences > Plugins on macOS, File > Settings > Plugins on Windows & Linux).

Select Marketplace, select the Flutter plugin and click Install.

1. In the target selector, select an Android device for running the app. If none are listed as available, select Tools> Android > AVD Manager and create one there. For details, see Managing AVDs.

dart:ui:1: Error: Not found: dart:ui. flutter/dart:

https://stackoverflow.com/questions/52483773/dartui1-error-not-found-dartui-flutter-dart

When running the app, you will find 2 main.dart Choose the one with the flutter icon beside it 

Magically if you add:

import 'package:flutter/widgets.dart';

at the top of that file, and delete the existing configuration, it will run as flutter instead of dart.
https://github.com/flutter/flutter/issues/27826

https://flutter.dev/docs/get-started/codelab

• This example creates a Material app. Material is a visual design language that is standard on mobile and the web. Flutter offers a rich set of Material widgets.
• The main() method uses arrow (=>) notation. Use arrow notation for one-line functions or methods.
• The app extends StatelessWidget which makes the app itself a widget. In Flutter, almost everything is a widget, including alignment, padding, and layout.
• The Scaffold widget, from the Material library, provides a default app bar, title, and a body property that holds the widget tree for the home screen. The widget subtree can be quite complex.
• A widget’s main job is to provide a build() method that describes how to display the widget in terms of other, lower level widgets.
• The body for this example consists of a Center widget containing a Text child widget. The Center widget aligns its widget subtree to the center of the screen.

The pubspec file manages the assets and dependencies for a Flutter app. In pubspec.yaml, 

1. While viewing the pubspec in Android Studio’s editor view, click Packages get. This pulls the package into your project. You should see the following in the console:
   
   

   $ flutter pub get
   Running "flutter pub get" in startup_namer...
   Process finished with exit code 0
   

   Performing Packages get also auto-generates the pubspec.lock file with a list of all packages pulled into the project and their version numbers.

source code:
https://github.com/flutter/codelabs/tree/master/startup_namer
If you would like to extend this app, proceed to part 2 on the Google Developers Codelabs site
https://codelabs.developers.google.com/