YaruCompactLayout: replace "page item" with indexed builders (#250)

Same as #248 but for the compact layout.

example/lib/main.dart

@@ -82,13 +82,20 @@ class _CompactPage extends StatelessWidget {
   Widget build(BuildContext context) {
     final width = MediaQuery.of(context).size.width;
 
+    final pageItems = [configItem] + examplePageItems;
+
     return YaruCompactLayout(
       style: width > 1000
           ? YaruNavigationRailStyle.labelledExtended
           : width > 500
               ? YaruNavigationRailStyle.labelled
               : YaruNavigationRailStyle.compact,
-      pageItems: [configItem] + examplePageItems,
+      length: pageItems.length,
+      iconBuilder: (context, index, selected) =>
+          pageItems[index].iconBuilder(context, selected),
+      titleBuilder: (context, index, selected) =>
+          pageItems[index].titleBuilder(context),
+      pageBuilder: (context, index) => pageItems[index].builder(context),
     );
   }
 }

lib/src/pages/layouts/yaru_compact_layout.dart

@@ -2,18 +2,36 @@ import 'package:flutter/material.dart';
 import 'package:yaru/yaru.dart';
 import '../../../yaru_widgets.dart';
 
+typedef YaruCompactLayoutBuilder = Widget Function(
+  BuildContext context,
+  int index,
+  bool selected,
+);
+
 /// A page layout which use a [YaruNavigationRail] on left for page navigation
 class YaruCompactLayout extends StatefulWidget {
   const YaruCompactLayout({
     super.key,
-    required this.pageItems,
+    required this.length,
+    required this.iconBuilder,
+    required this.titleBuilder,
+    required this.pageBuilder,
     this.style = YaruNavigationRailStyle.compact,
     this.initialIndex = 0,
     this.onSelected,
   });
 
-  /// A list of page destinations
-  final List<YaruPageItem> pageItems;
+  /// The total number of pages.
+  final int length;
+
+  /// A builder that is called for each page to build its icon.
+  final YaruCompactLayoutBuilder iconBuilder;
+
+  /// A builder that is called for each page to build its title.
+  final YaruCompactLayoutBuilder titleBuilder;
+
+  /// A builder that is called for each page to build its content.
+  final IndexedWidgetBuilder pageBuilder;
 
   /// Define the navigation rail style, see [YaruNavigationRailStyle]
   final YaruNavigationRailStyle style;
@@ -78,15 +96,14 @@ class _YaruCompactLayoutState extends State<YaruCompactLayout> {
             style: widget.style,
             selectedIndex: _index,
             onDestinationSelected: (index) {
-              if (widget.pageItems[index].onTap != null) {
-                widget.pageItems[index].onTap!.call(context);
-              }
               setState(() {
                 _index = index;
                 widget.onSelected?.call(index);
               });
             },
-            destinations: widget.pageItems,
+            length: widget.length,
+            iconBuilder: widget.iconBuilder,
+            titleBuilder: widget.titleBuilder,
           ),
         ),
       ),
@@ -107,9 +124,9 @@ class _YaruCompactLayoutState extends State<YaruCompactLayout> {
           pages: [
             MaterialPage(
               key: ValueKey(_index),
-              child: widget.pageItems.length > _index
-                  ? widget.pageItems[_index].builder(context)
-                  : widget.pageItems[0].builder(context),
+              child: widget.length > _index
+                  ? widget.pageBuilder(context, _index)
+                  : widget.pageBuilder(context, 0),
             ),
           ],
           onPopPage: (route, result) => route.didPop(result),

lib/src/pages/layouts/yaru_navigation_rail.dart

@@ -19,22 +19,26 @@ const _kSelectedIconAnimationDuration = Duration(milliseconds: 250);
 class YaruNavigationRail extends StatelessWidget {
   const YaruNavigationRail({
     super.key,
-    required this.destinations,
+    required this.length,
+    required this.iconBuilder,
+    required this.titleBuilder,
     required this.selectedIndex,
     required this.onDestinationSelected,
     this.style = YaruNavigationRailStyle.compact,
-  })  : assert(destinations.length >= 2),
+  })  : assert(length >= 2),
         assert(
           selectedIndex == null ||
-              (0 <= selectedIndex && selectedIndex < destinations.length),
+              (0 <= selectedIndex && selectedIndex < length),
         );
 
-  /// Defines the appearance of the button items that are arrayed within the
-  /// navigation rail.
-  ///
-  /// The value must be a list of two or more [YaruPageItem]
-  /// values.
-  final List<YaruPageItem> destinations;
+  /// The total number of pages.
+  final int length;
+
+  /// A builder that is called for each page to build its icon.
+  final YaruCompactLayoutBuilder iconBuilder;
+
+  /// A builder that is called for each page to build its title.
+  final YaruCompactLayoutBuilder titleBuilder;
 
   /// The index into [destinations] for the current selected
   /// [YaruPageItem] or null if no destination is selected.
@@ -56,11 +60,12 @@ class YaruNavigationRail extends StatelessWidget {
       padding: const EdgeInsets.symmetric(vertical: 5),
       child: Column(
         children: <Widget>[
-          for (int i = 0; i < destinations.length; i += 1)
+          for (int i = 0; i < length; i += 1)
             _YaruNavigationRailItem(
               i,
               i == selectedIndex,
-              destinations[i],
+              iconBuilder,
+              titleBuilder,
               onDestinationSelected,
               style,
             )
@@ -74,14 +79,16 @@ class _YaruNavigationRailItem extends StatefulWidget {
   const _YaruNavigationRailItem(
     this.index,
     this.selected,
-    this.destination,
+    this.iconBuilder,
+    this.titleBuilder,
     this.onDestinationSelected,
     this.style,
   );
 
   final int index;
   final bool selected;
-  final YaruPageItem destination;
+  final YaruCompactLayoutBuilder iconBuilder;
+  final YaruCompactLayoutBuilder titleBuilder;
   final ValueChanged<int>? onDestinationSelected;
   final YaruNavigationRailStyle style;
 
@@ -199,8 +206,9 @@ class _YaruNavigationRailItemState extends State<_YaruNavigationRailItem> {
           vertical: 2,
           horizontal: 10,
         ),
-        child: widget.destination.iconBuilder(
+        child: widget.iconBuilder(
           context,
+          widget.index,
           widget.selected,
         ),
       ),
@@ -216,7 +224,7 @@ class _YaruNavigationRailItemState extends State<_YaruNavigationRailItem> {
   }
 
   Widget _buildLabel(BuildContext context) {
-    var label = widget.destination.titleBuilder(context);
+    var label = widget.titleBuilder(context, widget.index, widget.selected);
 
     if (label is YaruPageItemTitle) {
       label = DefaultTextStyle.merge(