当标准flutter小部件具有硬编码主题（例如图标的颜色）时，扩展标准小部件的正确方法是什么？

2024-05-18 • 问答

我想更改标准颤动小部件 ExpansionPanel（）中使用的V形符号的颜色。这可以在 packages / flutter / lib / src / material / expansion_panel.dart 中找到。

但是我发现此人字形的图标颜色比 ExpandIcon（）中的图标颜色低一级。这在 packages / flutter / lib / src / material / expand_icon.dart

中

将expand_icon.dart拉入我的应用程序并更新/覆盖该硬编码颜色的正确方法是什么？

颜色定义如下：

  /// Default icon colors and opacities for when [Theme.brightness] is set to
  /// [Brightness.light] are based on the
  /// [Material Design system icon specifications](https://material.io/design/iconography/system-icons.html#color).
  /// Icon colors and opacities for [Brightness.dark] are based on the
  /// [Material Design dark theme specifications](https://material.io/design/color/dark-theme.html#ui-application)
  Color get _iconColor {
    if (widget.isExpanded && widget.expandedColor != null) {
      return widget.expandedColor;
    }

    if (widget.color != null) {
      return widget.color;
    }

    switch(Theme.of(context).brightness) {
      case Brightness.light:
        return Colors.black54;   // want to change this!!!
      case Brightness.dark:
        return Colors.white60;   // want to change this!!!

    }

    assert(false);
    return null;
  }

mixin MyNewColors { get newIconColor { //... switch (Theme.of(context).brightness) { case Brightness.light: return Colors.orange; // or the colors you want to change!!! case Brightness.dark: return Colors.blue; // or colors you want to change!!! } // ... } } class MyColor extends Color with MyNewColors { // ··· }

当标准flutter小部件具有硬编码主题（例如图标的颜色）时，扩展标准小部件的正确方法是什么？

aiai0525 回答：当标准flutter小部件具有硬编码主题（例如图标的颜色）时，扩展标准小部件的正确方法是什么？

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