解决 The argument type 'Icon' can't be assigned to the parameter type 'IconData'

IconData 类型

class IconData {
  /// Creates icon data.
  ///
  /// Rarely used directly. Instead, consider using one of the predefined icons
  /// like the [Icons] collection.
  ///
  /// The [fontPackage] argument must be non-null when using a font family that
  /// is included in a package. This is used when selecting the font.
  const IconData(
    this.codePoint, {
    this.fontFamily,
    this.fontPackage,
    this.matchTextDirection = false,
  });

  /// The Unicode code point at which this icon is stored in the icon font.
  final int codePoint;

  /// The font family from which the glyph for the [codePoint] will be selected.
  final String? fontFamily;

  /// The name of the package from which the font family is included.
  ///
  /// The name is used by the [Icon] widget when configuring the [TextStyle] so
  /// that the given [fontFamily] is obtained from the appropriate asset.
  ///
  /// See also:
  ///
  ///  * [TextStyle], which describes how to use fonts from other packages.
  final String? fontPackage;

  /// Whether this icon should be automatically mirrored in right-to-left
  /// environments.
  ///
  /// The [Icon] widget respects this value by mirroring the icon when the
  /// [Directionality] is [TextDirection.rtl].
  final bool matchTextDirection;

  @override
  bool operator ==(Object other) {
    if (other.runtimeType != runtimeType) {
      return false;
    }
    return other is IconData
        && other.codePoint == codePoint
        && other.fontFamily == fontFamily
        && other.fontPackage == fontPackage
        && other.matchTextDirection == matchTextDirection;
  }

  @override
  int get hashCode => Object.hash(codePoint, fontFamily, fontPackage, matchTextDirection);

  @override
  String toString() => 'IconData(U+${codePoint.toRadixString(16).toUpperCase().padLeft(5, '0')})';
}

使用

IconData(
  //code
  61454,
  //字体
  fontFamily: 'FontAwesome'
),

CupertinoIcons 的源码

class CupertinoIcons {
  // This class is not meant to be instantiated or extended; this constructor
  // prevents instantiation and extension.
  CupertinoIcons._();

  /// The icon font used for Cupertino icons.
  static const String iconFont = 'CupertinoIcons';

  /// The dependent package providing the Cupertino icons font.
  static const String iconFontPackage = 'cupertino_icons';

  // ===========================================================================
  // BEGIN LEGACY PRE SF SYMBOLS NAMES
  // We need to leave them as-is with the same codepoints for backward
  // compatibility with cupertino_icons <0.1.3.

  /// <i class='cupertino-icons md-36'>chevron_left</i> &#x2014; Cupertino icon for a thin left chevron.
  /// This is the same icon as [chevron_left] in cupertino_icons 1.0.0+.
  static const IconData left_chevron = IconData(0xf3d2, fontFamily: iconFont, fontPackage: iconFontPackage, matchTextDirection: true);

通过 CupertinoIcons.left_chevron 获取 IconData 类型的数据