Onboarding Screen

onboarding_screen.dart

class Screen extends StatelessWidget {
  const Screen({
    Key key,
    this.topFlex = 1,
    this.topText = "",
    this.topImageUri = "",
    this.bottomFlex = 1,
    this.bottomText = "",
    this.bottomImageUri = "",
  }) : super(key: key);

  final int topFlex;
  final String topText;
  final String topImageUri;
  final int bottomFlex;
  final String bottomText;
  final String bottomImageUri;

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: <Widget>[
        Expanded(
          child: Container(
            color: topImageUri == ""
                ? Theme.of(context).scaffoldBackgroundColor
                : null,
            padding: topImageUri == ""
                ? const EdgeInsets.all(16)
                : const EdgeInsets.fromLTRB(16, 0, 16, 0),
            alignment: topImageUri == "" ? Alignment.center : null,
            child: topImageUri != ""
                ? Image.asset(
                    topImageUri,
                    fit: BoxFit.cover,
                    alignment: Alignment.bottomCenter,
                  )
                : Text(
                    topText,
                    style: Theme.of(context).textTheme.display2,
                    textAlign: TextAlign.center,
                  ),
          ),
          flex: topFlex,
        ),
        Expanded(
          child: Container(
            color: bottomImageUri == ""
                ? Theme.of(context).scaffoldBackgroundColor
                : null,
            alignment: bottomImageUri == "" ? Alignment.center : null,
            padding: bottomImageUri == ""
                ? const EdgeInsets.all(30)
                : const EdgeInsets.fromLTRB(40, 30, 40, 0),
            child: bottomImageUri != ""
                ? Image.asset(
                    bottomImageUri,
                    fit: BoxFit.cover,
                    alignment: Alignment.topCenter,
                  )
                : Text(
                    bottomText,
                    style: Theme.of(context).textTheme.display2,
                    textAlign: TextAlign.center,
                  ),
          ),
          flex: bottomFlex,
        ),
      ],
    );
  }
}