Widget

Sizebox + Container
Divider的height实际为最外层高度，thickness才是真正的内容高，indent和endIndent为当margin实现

@override
  Widget build(BuildContext context) {
    final DividerThemeData dividerTheme = DividerTheme.of(context);
    final double height = this.height ?? dividerTheme.space ?? 16.0;
    final double thickness = this.thickness ?? dividerTheme.thickness ?? 0.0;
    final double indent = this.indent ?? dividerTheme.indent ?? 0.0;
    final double endIndent = this.endIndent ?? dividerTheme.endIndent ?? 0.0;
    return SizedBox(
      height: height,
      child: Center(
        child: Container(
          height: thickness,
          margin: EdgeInsetsDirectional.only(start: indent, end: endIndent),
          decoration: BoxDecoration(
            border: Border(
              bottom: createBorderSide(context, color: color, width: thickness),
            ),
          ),
        ),
      ),
    );
  }

style

用的直接是Divider皮肤

 final DividerThemeData dividerTheme = DividerTheme.of(context);