Merge pull request #3 from vishnukvmd/patch-1

Provide the latest scroll index to DraggableScrollbar
deakjahn · Apr 20, 2021 · be55f05 · be55f05 · deakjahn · Apr 20, 2021
2 parents a3f1c3e + 98ff789
commit be55f05
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Showing 2 changed files with 7 additions and 4 deletions.
diff --git a/lib/src/draggable_scrollbar.dart b/lib/src/draggable_scrollbar.dart
@@ -35,6 +35,7 @@ class DraggableScrollbar extends StatefulWidget {
 
 class DraggableScrollbarState extends State<DraggableScrollbar> with TickerProviderStateMixin {
   double thumbOffset = 0.0;
+  int currentFirstIndex;
   bool isDragging = false;
 
   double get thumbMin => 0.0;
@@ -45,6 +46,7 @@ class DraggableScrollbarState extends State<DraggableScrollbar> with TickerProvi
   void initState() {
     super.initState();
 
+    this.currentFirstIndex = widget.currentFirstIndex;
     if (widget.initialScrollIndex > 0 && widget.totalCount > 1) {
       WidgetsBinding.instance?.addPostFrameCallback((_) {
         setState(() => thumbOffset = (widget.initialScrollIndex / widget.totalCount) * (thumbMax - thumbMin));
@@ -79,12 +81,13 @@ class DraggableScrollbarState extends State<DraggableScrollbar> with TickerProvi
           alignment: Alignment.topRight,
           margin: EdgeInsets.only(top: thumbOffset),
           padding: widget.padding,
-          child: widget.scrollThumbBuilder.call(widget.backgroundColor, widget.drawColor, widget.heightScrollThumb, widget.currentFirstIndex),
+          child: widget.scrollThumbBuilder.call(widget.backgroundColor, widget.drawColor, widget.heightScrollThumb, this.currentFirstIndex),
         ),
       );
 
-  void setPosition(double position) {
+  void setPosition(double position, int currentFirstIndex) {
     setState(() {
+      this.currentFirstIndex = currentFirstIndex;
       thumbOffset = position * (thumbMax - thumbMin);
     });
   }

diff --git a/lib/src/huge_listview.dart b/lib/src/huge_listview.dart
@@ -115,7 +115,7 @@ class HugeListViewState<T> extends State<HugeListView<T>> {
   void _sendScroll() {
     int current = _currentFirst();
     widget.firstShown?.call(current);
-    scrollKey.currentState?.setPosition(current / widget.totalCount);
+    scrollKey.currentState?.setPosition(current / widget.totalCount, current);
   }
 
   int _currentFirst() {
@@ -212,7 +212,7 @@ class HugeListViewState<T> extends State<HugeListView<T>> {
   /// Jump to the [position] in the list. [position] is between 0.0 (first item) and 1.0 (last item), practically currentIndex / totalCount.
   /// To jump to a specific item, use [ItemScrollController.jumpTo] or [ItemScrollController.scrollTo].
   void setPosition(double position) {
-    scrollKey.currentState?.setPosition(position);
+    scrollKey.currentState?.setPosition(position, _currentFirst());
   }
 }