Fix scroll value issue when scrollOffset is less than distance from w…

…indow (#223)
Flipkart · Aug 3, 2018 · a0e665c · a0e665c
1 parent 9ccfbdb
commit a0e665c
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Showing 2 changed files with 8 additions and 5 deletions.
diff --git a/src/core/RecyclerListView.tsx b/src/core/RecyclerListView.tsx
@@ -300,11 +300,7 @@ export default class RecyclerListView<P extends RecyclerListViewProps, S extends
 
     public getCurrentScrollOffset(): number {
         const viewabilityTracker = this._virtualRenderer.getViewabilityTracker();
-        let currentOffset = (viewabilityTracker ? viewabilityTracker.getLastOffset() : 0);
-        if (currentOffset > this.props.distanceFromWindow!) {
-            currentOffset += this.props.distanceFromWindow!;
-        }
-        return currentOffset;
+        return viewabilityTracker ? viewabilityTracker.getLastActualOffset() + this.props.distanceFromWindow! : 0;
     }
 
     public findApproxFirstVisibleIndex(): number {

diff --git a/src/core/ViewabilityTracker.ts b/src/core/ViewabilityTracker.ts
@@ -19,6 +19,7 @@ export default class ViewabilityTracker {
     public onEngagedRowsChanged: TOnItemStatusChanged | null;
 
     private _currentOffset: number;
+    private _actualOffset: number;
     private _maxOffset: number;
     private _renderAheadOffset: number;
     private _visibleWindow: Range;
@@ -32,6 +33,7 @@ export default class ViewabilityTracker {
 
     constructor(renderAheadOffset: number, initialOffset: number) {
         this._currentOffset = Math.max(0, initialOffset);
+        this._actualOffset = this._currentOffset;
         this._maxOffset = 0;
         this._renderAheadOffset = renderAheadOffset;
         this._visibleWindow = { start: 0, end: 0 };
@@ -75,6 +77,7 @@ export default class ViewabilityTracker {
     }
 
     public updateOffset(offset: number): void {
+        this._actualOffset = offset;
         offset = Math.min(this._maxOffset, Math.max(0, offset));
         if (this._currentOffset !== offset) {
             this._currentOffset = offset;
@@ -91,6 +94,10 @@ export default class ViewabilityTracker {
         return this._currentOffset;
     }
 
+    public getLastActualOffset(): number {
+        return this._actualOffset;
+    }
+
     public getEngagedIndexes(): number[] {
         return this._engagedIndexes;
     }