From fd31bfad9f360ef415a0118c647e8fcf0097116c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B4=94=E6=99=A8=E6=99=96?= <catoldcui@gmail.com>
Date: Tue, 18 Dec 2018 00:32:11 +0800
Subject: [PATCH] correct offset when scrollController with initialScrollOffset

---
 lib/draggable_scrollbar.dart | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/draggable_scrollbar.dart b/lib/draggable_scrollbar.dart
index 9573486..dd3526c 100755
--- a/lib/draggable_scrollbar.dart
+++ b/lib/draggable_scrollbar.dart
@@ -346,6 +346,16 @@ class _DraggableScrollbarState extends State<DraggableScrollbar>
       parent: _labelAnimationController,
       curve: Curves.fastOutSlowIn,
     );
+
+    WidgetsBinding.instance.addPostFrameCallback((_) =>
+        _initOffsetForScrollInitialOffset());
+  }
+
+  /// init offset when widgets finish loading
+  void _initOffsetForScrollInitialOffset() {
+    _viewOffset = widget.controller.initialScrollOffset;
+    _barOffset = _viewOffset / viewMaxScrollExtent * barMaxScrollExtent;
+    setState(() {});
   }
 
   @override