scroll to current rank

Signed-off-by: dom <githubaccount56556@proton.me>

lib/pages/rank/controller.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:PiliPlus/models/common/rank_type.dart';
 import 'package:PiliPlus/pages/common/common_controller.dart';
 import 'package:PiliPlus/pages/rank/zone/controller.dart';
+import 'package:flutter/foundation.dart' show clampDouble;
 import 'package:flutter/material.dart';
 import 'package:get/get.dart';
 
@@ -19,6 +20,22 @@ class RankController extends GetxController
   @override
   ScrollController get scrollController => controller.scrollController;
 
+  final tabScrollController = ScrollController();
+
+  void scrollToCurrentIndex(double tabHeight, int index) {
+    final position = tabScrollController.position;
+    final offset = clampDouble(
+      (tabHeight * (2 * index + 1) - position.viewportDimension) / 2.0 + 80.0,
+      position.minScrollExtent,
+      position.maxScrollExtent,
+    );
+    tabScrollController.animateTo(
+      offset,
+      duration: kTabScrollDuration,
+      curve: Curves.ease,
+    );
+  }
+
   @override
   void onInit() {
     super.onInit();
@@ -28,6 +45,7 @@ class RankController extends GetxController
   @override
   void onClose() {
     tabController.dispose();
+    tabScrollController.dispose();
     super.onClose();
   }