set default font for fllutter application code example

Example 1: flutter change android default font size

/// Android has different 'textscalefactor' settings, like:
  /// 'Small: 0.85', 'Default: 1.0', 'Large: 1.15', 'Largest: 1.3'
/// To make sure the text in your app stays as you intended it to,
  /// use the MediaQuery Widget to overwrite the system default:
@override
  Widget build(BuildContext context) {
    return MediaQuery(
      data: MediaQuery.of(context).copyWith(textScaleFactor: 1.15), // Large
      child: Scaffold(),
    ),
  };

Example 2: https://flutter.dev/custom-fonts/#from-packages

flutter:
  fonts:
    - family: Raleway
      fonts:
        - asset: fonts/Raleway-Regular.ttf
        - asset: fonts/Raleway-Italic.ttf
          style: italic
    - family: RobotoMono
      fonts:
        - asset: fonts/RobotoMono-Regular.ttf
        - asset: fonts/RobotoMono-Bold.ttf
          weight: 700