Ability added to use custom icons along with default icons in Node Le…

packages/flutter_simple_treeview/example/lib/trees/controller_usage.dart

@@ -59,18 +59,20 @@ class _ControllerUsageState extends State<ControllerUsage> {
   Widget buildTree() {
     return TreeView(
       treeController: _controller,
+      primaryIcon: Icon(Icons.check_box_outline_blank),
+      secondaryIcon: Icon(Icons.check_box),
       nodes: [
         TreeNode(content: Text("node 1")),
         TreeNode(
-          content: Icon(Icons.audiotrack),
+          content: Text("Icons.audiotrack"),
           children: [
             TreeNode(content: Text("node 21")),
             TreeNode(
               content: Text("node 22"),
               key: _key,
               children: [
                 TreeNode(
-                  content: Icon(Icons.sentiment_very_satisfied),
+                  content: Text("Icons.sentiment_very_satisfied"),
                 ),
               ],
             ),

packages/flutter_simple_treeview/lib/src/builder.dart

@@ -11,8 +11,14 @@ import 'primitives/tree_controller.dart';
 import 'primitives/tree_node.dart';
 
 /// Builds set of [nodes] respecting [state], [indent] and [iconSize].
-Widget buildNodes(Iterable<TreeNode> nodes, double? indent,
-    TreeController state, double? iconSize) {
+Widget buildNodes(
+  Iterable<TreeNode> nodes,
+  double? indent,
+  TreeController state,
+  double? iconSize,
+    Widget? primaryIcon,
+    Widget? secondaryIcon,
+) {
   return Column(
     crossAxisAlignment: CrossAxisAlignment.start,
     children: [
@@ -22,6 +28,8 @@ Widget buildNodes(Iterable<TreeNode> nodes, double? indent,
           indent: indent,
           state: state,
           iconSize: iconSize,
+          primaryIcon: primaryIcon,
+          secondaryIcon: secondaryIcon,
         )
     ],
   );

packages/flutter_simple_treeview/lib/src/node_widget.dart

@@ -16,23 +16,26 @@ class NodeWidget extends StatefulWidget {
   final double? indent;
   final double? iconSize;
   final TreeController state;
+  final Widget? primaryIcon;
+  final Widget? secondaryIcon;
 
-  const NodeWidget(
-      {Key? key,
-      required this.treeNode,
-      this.indent,
-      required this.state,
-      this.iconSize})
-      : super(key: key);
+  const NodeWidget({
+    Key? key,
+    required this.treeNode,
+    this.indent,
+    required this.state,
+    this.iconSize,
+    this.primaryIcon,
+    this.secondaryIcon,
+  }) : super(key: key);
 
   @override
   _NodeWidgetState createState() => _NodeWidgetState();
 }
 
 class _NodeWidgetState extends State<NodeWidget> {
   bool get _isLeaf {
-    return widget.treeNode.children == null ||
-        widget.treeNode.children!.isEmpty;
+    return widget.treeNode.children == null || widget.treeNode.children!.isEmpty;
   }
 
   bool get _isExpanded {
@@ -44,32 +47,40 @@ class _NodeWidgetState extends State<NodeWidget> {
     var icon = _isLeaf
         ? null
         : _isExpanded
-            ? Icons.expand_more
-            : Icons.chevron_right;
+            ? widget.secondaryIcon ?? Icon(Icons.expand_more)
+            : widget.primaryIcon ?? Icon(Icons.chevron_right);
 
-    var onIconPressed = _isLeaf
-        ? null
-        : () => setState(
-            () => widget.state.toggleNodeExpanded(widget.treeNode.key!));
+    var onIconPressed = _isLeaf ? null : () => setState(() => widget.state.toggleNodeExpanded(widget.treeNode.key!));
 
     return Column(
       crossAxisAlignment: CrossAxisAlignment.start,
       children: [
         Row(
           children: [
-            IconButton(
-              iconSize: widget.iconSize ?? 24.0,
-              icon: Icon(icon),
-              onPressed: onIconPressed,
+            Material(
+              child: InkWell(
+                borderRadius: BorderRadius.circular(2.00),
+                child: SizedBox.square(
+                  dimension: widget.iconSize ?? 24.0,
+                  child: icon,
+                ),
+                onTap: onIconPressed,
+              ),
             ),
             widget.treeNode.content,
           ],
         ),
         if (_isExpanded && !_isLeaf)
           Padding(
             padding: EdgeInsets.only(left: widget.indent!),
-            child: buildNodes(widget.treeNode.children!, widget.indent,
-                widget.state, widget.iconSize),
+            child: buildNodes(
+              widget.treeNode.children!,
+              widget.indent,
+              widget.state,
+              widget.iconSize,
+              widget.primaryIcon,
+              widget.secondaryIcon,
+            ),
           )
       ],
     );

packages/flutter_simple_treeview/lib/src/tree_view.dart

@@ -25,13 +25,21 @@ class TreeView extends StatefulWidget {
   /// Tree controller to manage the tree state.
   final TreeController? treeController;
 
-  TreeView(
-      {Key? key,
-      required List<TreeNode> nodes,
-      this.indent = 40,
-      this.iconSize,
-      this.treeController})
-      : nodes = copyTreeNodes(nodes),
+  /// This widget will be takes place of default icon when Node will not be in expanded state
+  final Widget? primaryIcon;
+
+  /// This widget will be takes place of default icon when Node will be in expanded state
+  final Widget? secondaryIcon;
+
+  TreeView({
+    Key? key,
+    required List<TreeNode> nodes,
+    this.indent = 40,
+    this.iconSize,
+    this.treeController,
+    this.primaryIcon,
+    this.secondaryIcon,
+  })  : nodes = copyTreeNodes(nodes),
         super(key: key);
 
   @override
@@ -50,6 +58,12 @@ class _TreeViewState extends State<TreeView> {
   @override
   Widget build(BuildContext context) {
     return buildNodes(
-        widget.nodes, widget.indent, _controller!, widget.iconSize);
+      widget.nodes,
+      widget.indent,
+      _controller!,
+      widget.iconSize,
+      widget.primaryIcon,
+      widget.secondaryIcon,
+    );
   }
 }