Added RenderBox? childAt(int index); to FloatColumnChildManager and related changes.

Author: ronjb

lib/src/float_column.dart

@@ -249,6 +249,12 @@ class _FloatColumnElement extends RenderObjectElement
   @override
   List<Object> get textAndWidgets => (widget as FloatColumn)._textAndWidgets;
 
+  @override
+  RenderBox? childAt(int index) {
+    // dmPrint('_FloatColumnElement childAt');
+    return _childElements[index]?.renderObject as RenderBox?;
+  }
+
   @override
   RenderBox? addOrUpdateChild(int index, {required RenderBox? after}) {
     // dmPrint('_FloatColumnElement createChild');

lib/src/float_column_child_manager.dart

@@ -9,6 +9,9 @@ abstract class FloatColumnChildManager {
   /// The resulting child widgets, built from `textAndWidgets`.
   HashMap<int, Widget?> get childWidgets;
 
+  /// Returns the child RenderBox at the given index.
+  RenderBox? childAt(int index);
+
   /// Adds or updates the child element at the given index.
   RenderBox? addOrUpdateChild(int index, {required RenderBox? after});
 

lib/src/render_float_column_ext.dart

@@ -472,6 +472,17 @@ class _RenderCursor {
     index--;
   }
 
+  /// Jumps to the child at the given index, if it exists.
+  bool jumpToIndex(int index) {
+    final newChild = rfc.childManager.childAt(index);
+    if (newChild == null) return false;
+    maybeChild = newChild;
+    previousChild =
+        (previousChild!.parentData! as FloatColumnParentData).previousSibling;
+    this.index = index;
+    return true;
+  }
+
   /// Updates the current child's widget and associated element.
   void updateCurrentChildWidget(Widget widget) {
     rfc.childManager.childWidgets[index] = widget;