2a7c487463
* Re-factor postlist with VirtualizedList * Remove react-native-invertible-scroll-view dependency * Fix navigator not being pass to post * Feedback review * Feedback second review
54 lines
2.5 KiB
JavaScript
54 lines
2.5 KiB
JavaScript
// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
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// See License.txt for license information.
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import {VirtualizedList} from 'react-native';
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/* eslint-disable */
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export default class Virtualized extends VirtualizedList {
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_onScroll = (e) => {
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if (this.props.onScroll) {
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this.props.onScroll(e);
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}
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const timestamp = e.timeStamp;
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const visibleLength = this._selectLength(e.nativeEvent.layoutMeasurement);
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const contentLength = this._selectLength(e.nativeEvent.contentSize);
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const offset = this._selectOffset(e.nativeEvent.contentOffset);
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const dt = Math.max(1, timestamp - this._scrollMetrics.timestamp);
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const dOffset = offset - this._scrollMetrics.offset;
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const velocity = dOffset / dt;
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this._scrollMetrics = {contentLength, dt, offset, timestamp, velocity, visibleLength};
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const {data, getItemCount, onEndReached, onEndReachedThreshold, windowSize} = this.props;
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this._updateViewableItems(data);
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if (!data) {
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return;
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}
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const distanceFromEnd = contentLength - visibleLength - offset;
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const itemCount = getItemCount(data);
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if (this.state.last === itemCount - 1 &&
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distanceFromEnd <= onEndReachedThreshold &&
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(this._hasDataChangedSinceEndReached ||
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this._scrollMetrics.contentLength !== this._sentEndForContentLength)) {
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// Only call onEndReached once for a given dataset + content length.
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this._hasDataChangedSinceEndReached = false;
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this._sentEndForContentLength = this._scrollMetrics.contentLength;
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onEndReached({distanceFromEnd});
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}
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const {first, last} = this.state;
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if ((first > 0 && velocity < 0) || (last < itemCount - 1 && velocity > 0)) {
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const distanceToContentEdge = Math.min(
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Math.abs(this._getFrameMetricsApprox(first).offset - offset),
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Math.abs(this._getFrameMetricsApprox(last).offset - (offset + visibleLength)),
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);
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const hiPri = distanceToContentEdge < (windowSize * visibleLength / 4);
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if (hiPri) {
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// Don't worry about interactions when scrolling quickly; focus on filling content as fast
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// as possible.
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this._updateCellsToRenderBatcher.dispose({abort: true});
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this._updateCellsToRender();
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return;
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}
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}
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this._updateCellsToRenderBatcher.schedule();
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};
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}
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