Fixing example
diff --git a/packages/flutter/lib/src/material/reorderable_list.dart b/packages/flutter/lib/src/material/reorderable_list.dart
index 1b874ef..ed6b815 100644
--- a/packages/flutter/lib/src/material/reorderable_list.dart
+++ b/packages/flutter/lib/src/material/reorderable_list.dart
@@ -23,7 +23,19 @@
/// removing the item at oldIndex from the list will
/// reduce the list's length by one.
/// Implementations will need to account for this
-/// when inserting before newIndex.
+/// when inserting before newIndex. Typically the [onReorder]
+/// callback adjusts its index parameters like this:
+///
+/// ```
+/// onReorder: (int oldIndex, int newIndex) {
+/// if (oldIndex < newIndex) {
+/// // removing the item at oldIndex will shorten the list by 1.
+/// newIndex -= 1;
+/// }
+/// ....
+/// }
+/// ```
+///
///
/// {@tool dartpad}
///
