final

lib/utils/shop_scroll_controller.dart

@@ -14,7 +14,7 @@ class ShopScrollController extends ScrollController {
     this.coordinator, {
     double initialScrollOffset = 0.0,
     this.keepScrollOffset = true,
-    this.debugLabel,
+    required this.debugLabel,
   })  : assert(initialScrollOffset != null),
         assert(keepScrollOffset != null),
         _initialScrollOffset = initialScrollOffset;
@@ -61,7 +61,7 @@ class ShopScrollController extends ScrollController {
         'ScrollController not attached to any scroll views.');
     assert(_positions.length == 1,
         'ScrollController attached to multiple scroll views.');
-    return _positions.single;
+    return _positions.single as ShopScrollPosition;
   }
 
   /// 可滚动小部件的当前滚动偏移量
@@ -83,12 +83,12 @@ class ShopScrollController extends ScrollController {
   /// 持续时间不能为零。 要在没有动画的情况下跳至特定值，请使用[jumpTo]。
   Future<void> animateTo(
     double offset, {
-    @required Duration duration,
-    @required Curve curve,
+    required Duration duration,
+    required Curve curve,
   }) {
     assert(_positions.isNotEmpty,
         'ScrollController not attached to any scroll views.');
-    final List<Future<void>> animations = List<Future<void>>(_positions.length);
+    final List<Future<void>> animations = List<Future<void>>.filled(_positions.length, Future<void>.value());
     for (int i = 0; i < _positions.length; i += 1)
       animations[i] =
           _positions[i].animateTo(offset, duration: duration, curve: curve);
@@ -149,7 +149,7 @@ class ShopScrollController extends ScrollController {
   ///     则它将是前一个实例。 当环境已更改并且[Scrollable]需要重新创建[ScrollPosition]
   ///     对象时，将使用此方法。 第一次创建[ScrollPosition]时为null。
   ScrollPosition createScrollPosition(ScrollPhysics physics,
-      ScrollContext context, ScrollPosition oldPosition) {
+      ScrollContext context, ScrollPosition? oldPosition) {
     return ShopScrollPosition(
       coordinator: coordinator,
       physics: physics,