[two_dimensional_scrollables] Adds generics to the callbacks and builders of TreeView

packages/two_dimensional_scrollables/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.1
+
+* Adds generics to the callbacks and builders of TreeView.
+
 ## 0.3.0
 
 * Adds new TreeView widget and associated classes.

packages/two_dimensional_scrollables/example/lib/tree_view/custom_tree.dart

@@ -105,7 +105,7 @@ class CustomTreeExampleState extends State<CustomTreeExample> {
 
   Widget _treeNodeBuilder(
     BuildContext context,
-    TreeViewNode<Object?> node,
+    TreeViewNode<String> node,
     AnimationStyle toggleAnimationStyle,
   ) {
     final bool isParentNode = node.children.isNotEmpty;
@@ -144,7 +144,7 @@ class CustomTreeExampleState extends State<CustomTreeExample> {
         // Spacer
         const SizedBox(width: 8.0),
         // Content
-        Text(node.content.toString()),
+        Text(node.content),
       ],
     );
   }
@@ -188,14 +188,14 @@ class CustomTreeExampleState extends State<CustomTreeExample> {
               controller: _horizontalController,
             ),
             tree: _tree,
-            onNodeToggle: (TreeViewNode<Object?> node) {
+            onNodeToggle: (TreeViewNode<String> node) {
               setState(() {
-                _selectedNode = node as TreeViewNode<String>;
+                _selectedNode = node;
               });
             },
             treeNodeBuilder: _treeNodeBuilder,
-            treeRowBuilder: (TreeViewNode<Object?> node) {
-              if (_selectedNode == (node as TreeViewNode<String>)) {
+            treeRowBuilder: (TreeViewNode<String> node) {
+              if (_selectedNode == node) {
                 return TreeRow(
                   extent: FixedTreeRowExtent(
                     node.children.isNotEmpty ? 60.0 : 50.0,

packages/two_dimensional_scrollables/example/lib/tree_view/simple_tree.dart

@@ -100,13 +100,13 @@ class TreeExampleState extends State<TreeExample> {
               controller: horizontalController,
             ),
             tree: _tree,
-            onNodeToggle: (TreeViewNode<Object?> node) {
+            onNodeToggle: (TreeViewNode<String> node) {
               setState(() {
-                _selectedNode = node as TreeViewNode<String>;
+                _selectedNode = node;
               });
             },
-            treeRowBuilder: (TreeViewNode<Object?> node) {
-              if (_selectedNode == (node as TreeViewNode<String>)) {
+            treeRowBuilder: (TreeViewNode<String> node) {
+              if (_selectedNode == node) {
                 return TreeView.defaultTreeRowBuilder(node).copyWith(
                   recognizerFactories: _getTapRecognizer(node),
                   backgroundDecoration: TreeRowDecoration(

packages/two_dimensional_scrollables/lib/src/tree_view/tree.dart

@@ -338,14 +338,14 @@ class TreeView<T> extends StatefulWidget {
   ///
   /// By default, if this is unset, the [TreeView.defaultTreeNodeBuilder] is
   /// used.
-  final TreeViewNodeBuilder treeNodeBuilder;
+  final TreeViewNodeBuilder<T> treeNodeBuilder;
 
   /// Builds the [TreeRow] that describes the row for the provided
   /// [TreeViewNode].
   ///
   /// By default, if this is unset, the [TreeView.defaultTreeRowBuilder]
   /// is used.
-  final TreeViewRowBuilder treeRowBuilder;
+  final TreeViewRowBuilder<T> treeRowBuilder;
 
   /// If provided, the controller can be used to expand and collapse
   /// [TreeViewNode]s, or lookup information about the current state of the
@@ -360,7 +360,7 @@ class TreeView<T> extends StatefulWidget {
   /// a result of being toggled.
   ///
   /// This will not be called if a [TreeViewNode] does not have any children.
-  final TreeViewNodeCallback? onNodeToggle;
+  final TreeViewNodeCallback<T>? onNodeToggle;
 
   /// The default [AnimationStyle] for expanding and collapsing nodes in the
   /// [TreeView].

packages/two_dimensional_scrollables/lib/src/tree_view/tree_core.dart

@@ -21,7 +21,7 @@ import 'tree.dart';
 ///
 ///   * [TreeViewNode.toggleNode], for controlling node expansion
 ///     programmatically.
-typedef TreeViewNodeCallback = void Function(TreeViewNode<Object?> node);
+typedef TreeViewNodeCallback<T> = void Function(TreeViewNode<T> node);
 
 /// A mixin for classes implementing a tree structure as expected by a
 /// [TreeViewController].

packages/two_dimensional_scrollables/lib/src/tree_view/tree_delegate.dart

@@ -12,16 +12,16 @@ import 'tree_span.dart';
 ///
 /// Used by the [TreeViewDelegateMixin.buildRow] to configure rows in the
 /// [TreeView].
-typedef TreeViewRowBuilder = TreeRow Function(TreeViewNode<Object?> node);
+typedef TreeViewRowBuilder<T> = TreeRow Function(TreeViewNode<T> node);
 
 /// Signature for a function that creates a [Widget] to represent the given
 /// [TreeViewNode] in the [TreeView].
 ///
 /// Used by [TreeView.treeRowBuilder] to build rows on demand for the
 /// tree.
-typedef TreeViewNodeBuilder = Widget Function(
+typedef TreeViewNodeBuilder<T> = Widget Function(
   BuildContext context,
-  TreeViewNode<Object?> node,
+  TreeViewNode<T> node,
   AnimationStyle toggleAnimationStyle,
 );
 

packages/two_dimensional_scrollables/pubspec.yaml

@@ -1,6 +1,6 @@
 name: two_dimensional_scrollables
 description: Widgets that scroll using the two dimensional scrolling foundation.
-version: 0.3.0
+version: 0.3.1
 repository: https://github.com/flutter/packages/tree/main/packages/two_dimensional_scrollables
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+two_dimensional_scrollables%22+
 

packages/two_dimensional_scrollables/test/tree_view/render_tree_test.dart

@@ -141,10 +141,10 @@ void main() {
       final List<String> log = <String>[];
       final TreeView<String> treeView = TreeView<String>(
         tree: treeNodes,
-        treeRowBuilder: (TreeViewNode<Object?> node) {
+        treeRowBuilder: (TreeViewNode<String> node) {
           if (node.depth! == 0) {
             return getTappableRow(
-              node as TreeViewNode<String>,
+              node,
               () {
                 log.add(node.content);
                 tapCounter++;
@@ -174,7 +174,7 @@ void main() {
       int exitCounter = 0;
       final TreeView<String> treeView = TreeView<String>(
         tree: treeNodes,
-        treeRowBuilder: (TreeViewNode<Object?> node) {
+        treeRowBuilder: (TreeViewNode<String> node) {
           if (node.depth! == 0) {
             return getMouseTrackingRow(
               onEnter: (_) => enterCounter++,
@@ -397,7 +397,7 @@ void main() {
 
         treeView = TreeView<String>(
           tree: treeNodes,
-          treeRowBuilder: (TreeViewNode<Object?> node) {
+          treeRowBuilder: (TreeViewNode<String> node) {
             if (node.depth! == 1) {
               // extent == 100
               return row;
@@ -766,7 +766,7 @@ void main() {
             controller: horizontalController,
           ),
           tree: treeNodes,
-          treeRowBuilder: (TreeViewNode<Object?> node) {
+          treeRowBuilder: (TreeViewNode<String> node) {
             return row.copyWith(
               backgroundDecoration: node.depth! == 0
                   ? rootBackgroundDecoration

packages/two_dimensional_scrollables/test/tree_view/tree_test.dart

@@ -130,7 +130,7 @@ void main() {
           controller: controller,
           treeNodeBuilder: (
             BuildContext context,
-            TreeViewNode<Object?> node,
+            TreeViewNode<String> node,
             AnimationStyle toggleAnimationStyle,
           ) {
             returnedController ??= TreeViewController.of(context);
@@ -153,7 +153,7 @@ void main() {
           tree: simpleNodeSet,
           treeNodeBuilder: (
             BuildContext context,
-            TreeViewNode<Object?> node,
+            TreeViewNode<String> node,
             AnimationStyle toggleAnimationStyle,
           ) {
             returnedController ??= TreeViewController.maybeOf(context);
@@ -454,9 +454,9 @@ void main() {
         home: TreeView<String>(
           tree: simpleNodeSet,
           controller: controller,
-          onNodeToggle: (TreeViewNode<Object?> node) {
+          onNodeToggle: (TreeViewNode<String> node) {
             toggled = true;
-            toggledNode = node as TreeViewNode<String>;
+            toggledNode = node;
           },
         ),
       ));
@@ -476,13 +476,13 @@ void main() {
         home: TreeView<String>(
           tree: simpleNodeSet,
           controller: controller,
-          onNodeToggle: (TreeViewNode<Object?> node) {
+          onNodeToggle: (TreeViewNode<String> node) {
             toggled = true;
-            toggledNode = node as TreeViewNode<String>;
+            toggledNode = node;
           },
           treeNodeBuilder: (
             BuildContext context,
-            TreeViewNode<Object?> node,
+            TreeViewNode<String> node,
             AnimationStyle toggleAnimationStyle,
           ) {
             final Duration animationDuration = toggleAnimationStyle.duration ??
@@ -510,7 +510,7 @@ void main() {
                   // Spacer
                   const SizedBox(width: 8.0),
                   // Content
-                  Text(node.content.toString()),
+                  Text(node.content),
                 ]),
               ),
             );
@@ -535,11 +535,11 @@ void main() {
           tree: simpleNodeSet,
           treeNodeBuilder: (
             BuildContext context,
-            TreeViewNode<Object?> node,
+            TreeViewNode<String> node,
             AnimationStyle toggleAnimationStyle,
           ) {
             style ??= toggleAnimationStyle;
-            return Text(node.content.toString());
+            return Text(node.content);
           },
         ),
       ));
@@ -558,11 +558,11 @@ void main() {
           toggleAnimationStyle: AnimationStyle.noAnimation,
           treeNodeBuilder: (
             BuildContext context,
-            TreeViewNode<Object?> node,
+            TreeViewNode<String> node,
             AnimationStyle toggleAnimationStyle,
           ) {
             style = toggleAnimationStyle;
-            return Text(node.content.toString());
+            return Text(node.content);
           },
         ),
       ));
@@ -580,11 +580,11 @@ void main() {
           ),
           treeNodeBuilder: (
             BuildContext context,
-            TreeViewNode<Object?> node,
+            TreeViewNode<String> node,
             AnimationStyle toggleAnimationStyle,
           ) {
             style ??= toggleAnimationStyle;
-            return Text(node.content.toString());
+            return Text(node.content);
           },
         ),
       ));
@@ -693,6 +693,31 @@ void main() {
       expect(find.text('Child 2:1'), findsNothing);
       expect(find.text('Root 3'), findsOneWidget);
     });
+
+    test('should use the generic type for callbacks and builders', () {
+      final TreeView<String> treeView = TreeView<String>(
+        tree: simpleNodeSet,
+        treeNodeBuilder: (
+          BuildContext context,
+          TreeViewNode<String> node,
+          AnimationStyle animationStyle,
+        ) {
+          return TreeView.defaultTreeNodeBuilder(
+            context,
+            node,
+            animationStyle,
+          );
+        },
+        treeRowBuilder: (TreeViewNode<String> node) {
+          return TreeView.defaultTreeRowBuilder(node);
+        },
+        onNodeToggle: (TreeViewNode<String> node) {},
+      );
+
+      expect(treeView.onNodeToggle, isA<TreeViewNodeCallback<String>>());
+      expect(treeView.treeNodeBuilder, isA<TreeViewNodeBuilder<String>>());
+      expect(treeView.treeRowBuilder, isA<TreeViewRowBuilder<String>>());
+    });
   });
 
   group('TreeViewport', () {