Flutter how to fill gredient color for raised button?

Question

I'm trying to render gradient button but on some device, gradient colors are not expanded like image below.

How can I fix this?
Thanks!

Code

class GradientButton extends StatelessWidget {
  final Widget child;
  final VoidCallback onPressed;
  const GradientButton({@required this.child, @required this.onPressed});
  @override
  Widget build(BuildContext context) {
    return RaisedButton(
      textColor: Colors.white,
      shape: StadiumBorder(),
      padding: const EdgeInsets.all(0.0),
      child: Container(
        decoration: BoxDecoration(
          gradient: LinearGradient(
            colors: <Color>[Color(0xff00F260), Color(0xff0575E6)],
          ),
        ),
        padding: EdgeInsets.all(8.0),
        child: child
        onPressed: onPressed,
      ),
    );
  }
}

Answer 1

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';

class GradientButton extends StatelessWidget {
  final Widget child;
  final VoidCallback onPressed;

  const GradientButton({Key key, this.onPressed, this.child}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      decoration: ShapeDecoration(
        shape: const StadiumBorder(),
        gradient: LinearGradient(
          colors: [Color(0xff00F260), Color(0xff0575E6)],
        ),
      ),
      child: MaterialButton(
        materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
        shape: const StadiumBorder(),
        child: child,
        onPressed: onPressed,
      ),
    );
  }
}

You also get some MaterialButton effects like Ripple on tap, Disabled when onPressed is null, etc. For the elevation set shadows property in ShapeDecoration

shadows: [
  BoxShadow(
      color: Colors.black54,
      spreadRadius: 0.5,
      blurRadius: 3,
      offset: Offset(1, 1))
]