Added iconColor and textColor properties to ExpansionTile (#78281)

packages/flutter/lib/src/material/expansion_tile.dart

@@ -20,12 +20,17 @@ const Duration _kExpand = Duration(milliseconds: 200);
 /// [ExpansionTile] to save and restore its expanded state when it is scrolled
 /// in and out of view.
 ///
+/// This class overrides the [ListTileTheme.iconColor] and [ListTileTheme.textColor]
+/// theme properties for its [ListTile]. These colors animate between values when
+/// the tile is expanded and collapsed: between [iconColor], [collapsedIconColor] and
+/// between [textColor] and [collapsedTextColor].
+///
 /// See also:
 ///
 ///  * [ListTile], useful for creating expansion tile [children] when the
 ///    expansion tile represents a sublist.
-///  * The "Expand/collapse" section of
-///    <https://material.io/components/lists#types>.
+///  * The "Expand and collapse" section of
+///    <https://material.io/components/lists#types>
 class ExpansionTile extends StatefulWidget {
   /// Creates a single-line [ListTile] with a trailing button that expands or collapses
   /// the tile to reveal or hide the [children]. The [initiallyExpanded] property must
@@ -35,7 +40,6 @@ class ExpansionTile extends StatefulWidget {
     this.leading,
     required this.title,
     this.subtitle,
-    this.backgroundColor,
     this.onExpansionChanged,
     this.children = const <Widget>[],
     this.trailing,
@@ -45,7 +49,12 @@ class ExpansionTile extends StatefulWidget {
     this.expandedCrossAxisAlignment,
     this.expandedAlignment,
     this.childrenPadding,
+    this.backgroundColor,
     this.collapsedBackgroundColor,
+    this.textColor,
+    this.collapsedTextColor,
+    this.iconColor,
+    this.collapsedIconColor,
   }) : assert(initiallyExpanded != null),
        assert(maintainState != null),
        assert(
@@ -147,6 +156,29 @@ class ExpansionTile extends StatefulWidget {
   /// When the value is null, the value of `childrenPadding` is [EdgeInsets.zero].
   final EdgeInsetsGeometry? childrenPadding;
 
+  /// The icon color of tile's [trailing] expansion icon when the
+  /// sublist is expanded.
+  ///
+  /// Used to override to the [ListTileTheme.iconColor].
+  final Color? iconColor;
+
+  /// The icon color of tile's [trailing] expansion icon when the
+  /// sublist is collapsed.
+  ///
+  /// Used to override to the [ListTileTheme.iconColor].
+  final Color? collapsedIconColor;
+
+
+  /// The color of the tile's titles when the sublist is expanded.
+  ///
+  /// Used to override to the [ListTileTheme.textColor].
+  final Color? textColor;
+
+  /// The color of the tile's titles when the sublist is collapsed.
+  ///
+  /// Used to override to the [ListTileTheme.textColor].
+  final Color? collapsedTextColor;
+
   @override
   _ExpansionTileState createState() => _ExpansionTileState();
 }
@@ -259,11 +291,11 @@ class _ExpansionTileState extends State<ExpansionTile> with SingleTickerProvider
     final ThemeData theme = Theme.of(context);
     _borderColorTween.end = theme.dividerColor;
     _headerColorTween
-      ..begin = theme.textTheme.subtitle1!.color
-      ..end = theme.accentColor;
+      ..begin = widget.collapsedTextColor ?? theme.textTheme.subtitle1!.color
+      ..end = widget.textColor ?? theme.accentColor;
     _iconColorTween
-      ..begin = theme.unselectedWidgetColor
-      ..end = theme.accentColor;
+      ..begin = widget.collapsedIconColor ?? theme.unselectedWidgetColor
+      ..end = widget.iconColor ?? theme.accentColor;
     _backgroundColorTween
       ..begin = widget.collapsedBackgroundColor
       ..end = widget.backgroundColor;

packages/flutter/test/material/expansion_tile_test.dart

@@ -520,4 +520,42 @@ void main() {
 
     expect(boxDecoration.color, backgroundColor);
   });
+
+  testWidgets('ExpansionTile iconColor, textColor', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/pull/78281
+
+    const Color iconColor = Color(0xff00ff00);
+    const Color collapsedIconColor = Color(0xff0000ff);
+    const Color textColor = Color(0xff00ffff);
+    const Color collapsedTextColor = Color(0xffff00ff);
+
+    await tester.pumpWidget(const MaterialApp(
+      home: Material(
+        child: ExpansionTile(
+          iconColor: iconColor,
+          collapsedIconColor: collapsedIconColor,
+          textColor: textColor,
+          collapsedTextColor: collapsedTextColor,
+          initiallyExpanded: false,
+          title: TestText('title'),
+          trailing: TestIcon(),
+          children: <Widget>[
+            SizedBox(height: 100, width: 100),
+          ],
+        ),
+      ),
+    ));
+
+    Color getIconColor() => tester.state<TestIconState>(find.byType(TestIcon)).iconTheme.color!;
+    Color getTextColor() => tester.state<TestTextState>(find.byType(TestText)).textStyle.color!;
+
+    expect(getIconColor(), collapsedIconColor);
+    expect(getTextColor(), collapsedTextColor);
+
+    await tester.tap(find.text('title'));
+    await tester.pumpAndSettle();
+
+    expect(getIconColor(), iconColor);
+    expect(getTextColor(), textColor);
+  });
 }