android - Flutter:未定义命名参数 'decoration'

Question

我正在尝试为我的应用程序的顶部编写一个栏，但我收到一条错误消息“未定义命名参数‘decoration’。”

import 'package:flutter/material.dart';

class GradientAppBar extends StatelessWidget {
  final String title;
  final double barHeight = 66.0;

  GradientAppBar(this.title);

  @override
  Widget build(BuildContext context) {
    final double statusBarHeight = MediaQuery.of(context).padding.top;

    return new Container(
      padding: new EdgeInsets.only(top: statusBarHeight),
      height: statusBarHeight + barHeight,
      child: new Center(
        child: new Text(title,
            style: const TextStyle(
                color: Colors.white,
                fontFamily: 'Poppins',
                fontWeight: FontWeight.w600,
                fontSize: 36.0)),
        decoration: new BoxDecoration(
          gradient: new LinearGradient(
              colors: [const Color(0xFF3366FF), const Color(0xFF00CCFF)],
              begin: const FractionalOffset(0.0, 0.0),
              end: const FractionalOffset(0.5, 0.0),
              stops: [0.0, 0.5],
              tileMode: TileMode.clamp),
        ),
      ),
    );
  }
}

有谁知道我为什么会收到这个错误？感谢您的帮助。

Answer 1

decoration 属性来自 Container 而不是 Center 小部件，所以只需移动它即可。

     return new Container(
          padding: new EdgeInsets.only(top: statusBarHeight),
          height: statusBarHeight + barHeight,
          child: new Center(
            child: new Text(title,
                style: const TextStyle(
                    color: Colors.white,
                    fontFamily: 'Poppins',
                    fontWeight: FontWeight.w600,
                    fontSize: 36.0)),
          ),

            decoration: new BoxDecoration(
              gradient: new LinearGradient(
                  colors: [const Color(0xFF3366FF), const Color(0xFF00CCFF)],
                  begin: const FractionalOffset(0.0, 0.0),
                  end: const FractionalOffset(0.5, 0.0),
                  stops: [0.0, 0.5],
                  tileMode: TileMode.clamp),
            ),
        );