fix(dropdown): apply expanded_insets to the DropdownMenu when expand is set

CHANGELOG.md

@@ -7,6 +7,7 @@
 
 ### Bug fixes
 
+* Fix `Dropdown.expanded_insets` having no effect when `expand` is set ([#6895](https://github.com/flet-dev/flet/issues/6895), [#6896](https://github.com/flet-dev/flet/pull/6896)) by @xsalaices.
 * Fix `Tabs` ignoring a new `selected_index` set together with a new `length` - e.g. inserting a tab before the selected one and moving `selected_index` to follow it selected the inserted tab instead ([#6901](https://github.com/flet-dev/flet/pull/6901)) by @FeodorFitsner.
 * Fix controls losing their state (a `TextField` its focus and cursor, a list its scroll position) when a sibling before them in a `Column`, `Row` or other multi-child control became visible or hidden: children were matched by position, so the shift rebuilt them. Children are now matched by control id ([#6901](https://github.com/flet-dev/flet/pull/6901)) by @FeodorFitsner.
 * Fix `FilePicker.upload()` with several files uploading the wrong file to each URL: after the first upload, each file's `id` pointed at the next picked file, so a file's bytes went to another file's URL and the last file never uploaded (its caller waited forever). Picked files now keep their `id` across `upload()` calls, and files that can't be found report an upload error ([#6901](https://github.com/flet-dev/flet/pull/6901)) by @FeodorFitsner.

packages/flet/lib/src/controls/dropdown.dart

@@ -226,7 +226,9 @@ class _DropdownControlState extends State<DropdownControl> {
     _focusNode.canRequestFocus = editable;
 
     int expand = widget.control.getExpand("expand", 0)!;
-    EdgeInsets? expandedInsets = expand > 0 ? EdgeInsets.zero : null;
+    EdgeInsets? expandedInsets = expand > 0
+        ? widget.control.getPadding("expanded_insets", EdgeInsets.zero)
+        : null;
 
     Widget dropDown = DropdownMenu<String>(
       key: dropdownMenuKey,

packages/flet/test/widgets/dropdown_test.dart

@@ -0,0 +1,91 @@
+import 'package:flet/src/controls/dropdown.dart';
+import 'package:flet/src/flet_backend.dart';
+import 'package:flet/src/models/control.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+class _TestBackend extends FletBackend {
+  _TestBackend()
+      : super(
+            pageUri: Uri.parse('http://localhost'),
+            assetsDir: '',
+            extensions: [],
+            multiView: false);
+}
+
+void main() {
+  testWidgets('Dropdown.expanded_insets is applied when expand is set',
+      (tester) async {
+    final backend = _TestBackend();
+    final control = Control(
+        id: 1,
+        type: 'Dropdown',
+        properties: {
+          'expand': 1,
+          'expanded_insets': {
+            'left': 40.0,
+            'top': 0.0,
+            'right': 40.0,
+            'bottom': 0.0
+          },
+          'options': [],
+        },
+        backend: backend);
+
+    await tester.pumpWidget(
+        MaterialApp(home: Scaffold(body: DropdownControl(control: control))));
+
+    expect(tester.takeException(), isNull);
+    final menu =
+        tester.widget<DropdownMenu<String>>(find.byType(DropdownMenu<String>));
+    expect(menu.expandedInsets, const EdgeInsets.fromLTRB(40, 0, 40, 0));
+  });
+
+  testWidgets(
+      'Dropdown falls back to zero insets when expand is set without expanded_insets',
+      (tester) async {
+    final backend = _TestBackend();
+    final control = Control(
+        id: 1,
+        type: 'Dropdown',
+        properties: {
+          'expand': 1,
+          'options': [],
+        },
+        backend: backend);
+
+    await tester.pumpWidget(
+        MaterialApp(home: Scaffold(body: DropdownControl(control: control))));
+
+    expect(tester.takeException(), isNull);
+    final menu =
+        tester.widget<DropdownMenu<String>>(find.byType(DropdownMenu<String>));
+    expect(menu.expandedInsets, EdgeInsets.zero);
+  });
+
+  testWidgets('Dropdown has null expandedInsets when not expanded',
+      (tester) async {
+    final backend = _TestBackend();
+    final control = Control(
+        id: 1,
+        type: 'Dropdown',
+        properties: {
+          'expanded_insets': {
+            'left': 40.0,
+            'top': 0.0,
+            'right': 40.0,
+            'bottom': 0.0
+          },
+          'options': [],
+        },
+        backend: backend);
+
+    await tester.pumpWidget(
+        MaterialApp(home: Scaffold(body: DropdownControl(control: control))));
+
+    expect(tester.takeException(), isNull);
+    final menu =
+        tester.widget<DropdownMenu<String>>(find.byType(DropdownMenu<String>));
+    expect(menu.expandedInsets, isNull);
+  });
+}