Template for ThemeData Material Design App Flutter

theme.dart

//  in main.dart: 
//  import 'package:fly_library/res/theme.dart' as Theme;

import 'package:flutter/material.dart';

final ThemeData myAppTheme = new ThemeData(
    brightness: Brightness.light,
    primarySwatch: Colors.blue,
    primaryColor: Colors.blue[500],
    primaryColorBrightness: Brightness.light,
    accentColor: Colors.pinkAccent[200],
    accentColorBrightness: Brightness.light);

theme_note.md

Create a [ThemeData] given a set of preferred values. Default values will be derived for arguments that are omitted.

The most useful values to give are, in order of importance:

• The desired theme [brightness].
• The primary color palette (the [primarySwatch]), chosen from one of the swatches defined by the material design spec. This should be one of the maps from the [Colors] class that do not have "accent" in their name.
• The [accentColor], sometimes called the secondary color, and, if the accent color is specified, its brightness ([accentColorBrightness]), so that the right contrasting text color will be used over the accent color.

See https://material.google.com/style/color.html for more discussion on how to pick the right colors.

https://docs.flutter.io/flutter/material/ThemeData-class.html