如何为自定义Flutter按钮添加内置Padding参数替代Padding组件？

方案一：改为组合式Widget（推荐，适配你的使用场景） #

把SdPrimaryButton改成继承StatelessWidget，自由整合Padding、SizedBox和ElevatedButton，彻底省去嵌套外层组件的麻烦：

class SdPrimaryButton extends StatelessWidget {
  final String title;
  final VoidCallback? onPressed;
  final VoidCallback? onLongPress;
  final EdgeInsetsGeometry padding;
  final bool isFullWidth; // 可选参数，控制按钮是否占满父容器宽度

  const SdPrimaryButton({
    super.key,
    required this.title,
    required this.onPressed,
    this.onLongPress,
    this.padding = EdgeInsets.zero, // 默认无padding，可自定义
    this.isFullWidth = false, // 默认不占满宽度
  });

  @override
  Widget build(BuildContext context) {
    // 基础按钮组件
    Widget button = ElevatedButton(
      onPressed: onPressed,
      onLongPress: onLongPress,
      style: ElevatedButton.styleFrom(),
      child: Text(title),
    );

    // 如果需要占满宽度，包裹SizedBox
    if (isFullWidth) {
      button = SizedBox(width: double.infinity, child: button);
    }

    // 包裹外层Padding
    return Padding(
      padding: padding,
      child: button,
    );
  }
}

调用示例 #

现在直接设置padding和isFullWidth参数即可，无需再嵌套Padding和SizedBox：

SdPrimaryButton(
  title: appLocalizations.labelContinue,
  onPressed: () {
    if (widget.checkValidation()) {
      widget.pageController!.nextPage(
        duration: const Duration(milliseconds: 500),
        curve: Curves.easeInOut,
      );
      _scrollToTop();
    }
  },
  padding: const EdgeInsets.symmetric(horizontal: medium * 2),
  isFullWidth: true,
)

方案二：保留继承ElevatedButton（仅适用于按钮内部padding） #

如果只想给按钮内部的文本添加padding，而非外层容器padding，可以直接在styleFrom中传入padding参数：

class SdPrimaryButton extends ElevatedButton {
  SdPrimaryButton({
    required String title,
    required VoidCallback? onPressed,
    VoidCallback? onLongPress,
    Key? key,
    EdgeInsetsGeometry padding = EdgeInsets.zero, // 添加padding参数
  }) : super(
          key: key,
          onPressed: onPressed,
          onLongPress: onLongPress,
          style: ElevatedButton.styleFrom(
            padding: padding, // 将padding应用到按钮内部
          ),
          child: Text(title),
        );
}

内容的提问来源于stack exchange，提问作者Kathrin