如何在应用栏 Flutter 中创建线性渐变？

Question

我正在尝试在 appBar 中添加线性渐变，但到目前为止我还没有设法做到这一点。 有人知道我如何在我的 appBar 中添加它吗？ 谢谢

decoration: BoxDecoration(
                gradient: LinearGradient(
                    colors: [const Color(0xFFF06292), const Color(0xff2A75BC)]),

我的代码看起来像这样

class RegisterAgree extends StatefulWidget {
  @override
  _RegisterAgreeState createState() => _RegisterAgreeState();
}

class _RegisterAgreeState extends State<RegisterAgree> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.pink,
        title: Row(
          children: <Widget>[
            Image.asset(
              'assets/images/logox.png',
              fit: BoxFit.cover,
              height: 45.0,
            )
          ],
        ),
      ),
    );
  }
}

Answer 1

你也可以使用这个：

appBar: AppBar(

  title: Text('Flutter Demo'),
  flexibleSpace: Container(
    decoration: BoxDecoration(
      gradient: LinearGradient(
        begin: Alignment.centerLeft,
        end: Alignment.centerRight,
        colors: <Color>[
          Colors.red,
          Colors.blue
        ],
      ),
    ),
  ),
),

Answer 2

您可以通过将AppBar包装在带有渐变的Container中来创建自己的可重用 appbar 小部件：

class GradientAppBar extends StatelessWidget with PreferredSizeWidget {
  static const _defaultHeight = 56.0;

  final double elevation;
  final Gradient gradient;
  final Widget title;
  final double barHeight;

  GradientAppBar(
      {this.elevation = 3.0,
      this.gradient,
      this.title,
      this.barHeight = _defaultHeight});

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 56.0,
      decoration: BoxDecoration(gradient: gradient, boxShadow: [
        BoxShadow(
          offset: Offset(0, elevation),
          color: Colors.black.withOpacity(0.3),
          blurRadius: 3,
        ),
      ]),
      child: AppBar(
        title: title,
        elevation: 0.0,
        backgroundColor: Colors.transparent,
      ),
    );
  }

  @override
  Size get preferredSize => Size.fromHeight(barHeight);
}

在 DartPad 上尝试完整的示例

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