Flutter-渐变背景色

1. 创建渐变色GradientBackground类

import 'package:flutter/material.dart';

class GradientBackground extends StatelessWidget {
  final Widget child;
  final Color color;

  GradientBackground({@required this.child, @required this.color});

  @override
  Widget build(BuildContext context) {
    return AnimatedContainer(
      decoration: BoxDecoration(
        // Box decoration takes a gradient
        gradient: LinearGradient(
          // Where the linear gradient begins and ends
          begin: Alignment.topRight,
          end: Alignment.bottomLeft,
          // Add one stop for each color. Stops should increase from 0 to 1
          stops: [0.3, 0.5, 0.7, 0.9],
          colors: getColorList(color)
        ),
      ),
      curve: Curves.linear,
      child: child, duration: Duration(milliseconds: 500),
    );
  }

  List getColorList(Color color) {
    if (color is MaterialColor) {
      return [
           color[300],
           color[600],
           color[700],
           color[900],
          ];
    } else {
      return List.filled(4, color);
    }
  }
}

2. 使用方法

 @override
  Widget build(BuildContext context) {
      return GradientBackground(
        color: backgroundColor,
        child: Scaffold(
                   .........
                  ）
       );
  }