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Fix bug in onAdd and onRemove

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Signed-off-by: RMidhunSuresh <rmidhunsuresh@gmail.com>
This commit is contained in:
RMidhunSuresh 2021-08-11 12:23:26 +05:30 committed by Bruno Windels
parent 1165683f69
commit 3ae52ea1ca
1 changed files with 11 additions and 7 deletions
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18
src/platform/web/ui/general/LazyListView.js
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@ -271,9 +271,15 @@ export class LazyListView extends ListView {
if (this._renderRange.containsIndex(idx)) { if (this._renderRange.containsIndex(idx)) {
const normalizedIdx = this._renderRange.normalize(idx); const normalizedIdx = this._renderRange.normalize(idx);
if (bottomCount === 0) { if (bottomCount === 0) {
// We're completely scrolled; so the extra element needs to be removed from top /*
this._removeChild(this._childInstances.shift()); If we're at the bottom of the list, we need to render the additional item
this._renderRange = new ItemRange(topCount + 1, renderCount, bottomCount); without removing another item from the list.
We can't increment topCount because the index topCount is not affected by the
add operation (and any modification will thus break ItemRange.normalize()).
We can't increment bottomCount because there's not enough items left to trigger
a further render.
*/
this._renderRange = new ItemRange(topCount, renderCount + 1, bottomCount);
} }
else { else {
// Remove the last element, render the new element // Remove the last element, render the new element
@ -295,10 +301,8 @@ export class LazyListView extends ListView {
const normalizedIdx = this._renderRange.normalize(idx); const normalizedIdx = this._renderRange.normalize(idx);
super.onRemove(normalizedIdx, value); super.onRemove(normalizedIdx, value);
if (bottomCount === 0) { if (bottomCount === 0) {
const child = this._childCreator(this._itemAtIndex(topCount - 1)); // See onAdd for explanation
this._childInstances.unshift(child); this._renderRange = new ItemRange(topCount, renderCount - 1, bottomCount);
this._root.insertBefore(mountView(child, this._mountArgs), this._root.firstChild);
this._renderRange = new ItemRange(topCount - 1, renderCount, bottomCount);
} }
else { else {
const child = this._childCreator(this._itemAtIndex(this._renderRange.lastIndex - 1)); const child = this._childCreator(this._itemAtIndex(this._renderRange.lastIndex - 1));