1338 lines
45 KiB
JavaScript
1338 lines
45 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule VirtualizedList
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* @flow
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* @format
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*/
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'use strict';
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const Batchinator = require('Batchinator');
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const FillRateHelper = require('FillRateHelper');
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const PropTypes = require('prop-types');
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const React = require('React');
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const ReactNative = require('ReactNative');
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const RefreshControl = require('RefreshControl');
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const ScrollView = require('ScrollView');
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const StyleSheet = require('StyleSheet');
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const View = require('View');
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const ViewabilityHelper = require('ViewabilityHelper');
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const flattenStyle = require('flattenStyle');
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const infoLog = require('infoLog');
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const invariant = require('fbjs/lib/invariant');
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const warning = require('fbjs/lib/warning');
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const {computeWindowedRenderLimits} = require('VirtualizeUtils');
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import type {StyleObj} from 'StyleSheetTypes';
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import type {ViewabilityConfig, ViewToken} from 'ViewabilityHelper';
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type Item = any;
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type renderItemType = (info: any) => ?React.Element<any>;
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type RequiredProps = {
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renderItem: renderItemType,
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/**
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* The default accessor functions assume this is an Array<{key: string}> but you can override
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* getItem, getItemCount, and keyExtractor to handle any type of index-based data.
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*/
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data?: any,
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/**
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* A generic accessor for extracting an item from any sort of data blob.
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*/
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getItem: (data: any, index: number) => ?Item,
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/**
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* Determines how many items are in the data blob.
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*/
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getItemCount: (data: any) => number,
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};
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type OptionalProps = {
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/**
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* `debug` will turn on extra logging and visual overlays to aid with debugging both usage and
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* implementation, but with a significant perf hit.
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*/
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debug?: ?boolean,
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/**
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* DEPRECATED: Virtualization provides significant performance and memory optimizations, but fully
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* unmounts react instances that are outside of the render window. You should only need to disable
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* this for debugging purposes.
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*/
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disableVirtualization: boolean,
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/**
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* A marker property for telling the list to re-render (since it implements `PureComponent`). If
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* any of your `renderItem`, Header, Footer, etc. functions depend on anything outside of the
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* `data` prop, stick it here and treat it immutably.
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*/
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extraData?: any,
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getItemLayout?: (
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data: any,
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index: number,
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) => {length: number, offset: number, index: number}, // e.g. height, y
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horizontal?: ?boolean,
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/**
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* How many items to render in the initial batch. This should be enough to fill the screen but not
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* much more. Note these items will never be unmounted as part of the windowed rendering in order
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* to improve perceived performance of scroll-to-top actions.
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*/
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initialNumToRender: number,
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/**
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* Instead of starting at the top with the first item, start at `initialScrollIndex`. This
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* disables the "scroll to top" optimization that keeps the first `initialNumToRender` items
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* always rendered and immediately renders the items starting at this initial index. Requires
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* `getItemLayout` to be implemented.
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*/
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initialScrollIndex?: ?number,
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/**
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* Reverses the direction of scroll. Uses scale transforms of -1.
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*/
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inverted?: ?boolean,
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keyExtractor: (item: Item, index: number) => string,
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/**
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* Each cell is rendered using this element. Can be a React Component Class,
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* or a render function. Defaults to using View.
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*/
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CellRendererComponent?: ?React.ComponentType<any>,
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/**
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* Rendered when the list is empty. Can be a React Component Class, a render function, or
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* a rendered element.
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*/
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ListEmptyComponent?: ?(React.ComponentType<any> | React.Element<any>),
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/**
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* Rendered at the bottom of all the items. Can be a React Component Class, a render function, or
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* a rendered element.
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*/
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ListFooterComponent?: ?(React.ComponentType<any> | React.Element<any>),
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/**
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* Rendered at the top of all the items. Can be a React Component Class, a render function, or
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* a rendered element.
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*/
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ListHeaderComponent?: ?(React.ComponentType<any> | React.Element<any>),
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/**
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* The maximum number of items to render in each incremental render batch. The more rendered at
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* once, the better the fill rate, but responsiveness my suffer because rendering content may
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* interfere with responding to button taps or other interactions.
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*/
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maxToRenderPerBatch: number,
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onEndReached?: ?(info: {distanceFromEnd: number}) => void,
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onEndReachedThreshold?: ?number, // units of visible length
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onLayout?: ?Function,
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/**
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* If provided, a standard RefreshControl will be added for "Pull to Refresh" functionality. Make
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* sure to also set the `refreshing` prop correctly.
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*/
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onRefresh?: ?Function,
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/**
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* Called when the viewability of rows changes, as defined by the
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* `viewabilityConfig` prop.
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*/
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onViewableItemsChanged?: ?(info: {
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viewableItems: Array<ViewToken>,
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changed: Array<ViewToken>,
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}) => void,
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/**
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* Set this when offset is needed for the loading indicator to show correctly.
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* @platform android
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*/
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progressViewOffset?: number,
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/**
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* Set this true while waiting for new data from a refresh.
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*/
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refreshing?: ?boolean,
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/**
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* Note: may have bugs (missing content) in some circumstances - use at your own risk.
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*
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* This may improve scroll performance for large lists.
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*/
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removeClippedSubviews?: boolean,
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/**
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* Render a custom scroll component, e.g. with a differently styled `RefreshControl`.
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*/
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renderScrollComponent?: (props: Object) => React.Element<any>,
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/**
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* Amount of time between low-pri item render batches, e.g. for rendering items quite a ways off
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* screen. Similar fill rate/responsiveness tradeoff as `maxToRenderPerBatch`.
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*/
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updateCellsBatchingPeriod: number,
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viewabilityConfig?: ViewabilityConfig,
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/**
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* Determines the maximum number of items rendered outside of the visible area, in units of
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* visible lengths. So if your list fills the screen, then `windowSize={21}` (the default) will
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* render the visible screen area plus up to 10 screens above and 10 below the viewport. Reducing
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* this number will reduce memory consumption and may improve performance, but will increase the
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* chance that fast scrolling may reveal momentary blank areas of unrendered content.
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*/
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windowSize: number,
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};
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/* $FlowFixMe - this Props seems to be missing a bunch of stuff. Remove this
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* comment to see the errors */
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export type Props = RequiredProps & OptionalProps;
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let _usedIndexForKey = false;
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type State = {first: number, last: number};
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/**
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* Base implementation for the more convenient [`<FlatList>`](/react-native/docs/flatlist.html)
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* and [`<SectionList>`](/react-native/docs/sectionlist.html) components, which are also better
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* documented. In general, this should only really be used if you need more flexibility than
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* `FlatList` provides, e.g. for use with immutable data instead of plain arrays.
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*
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* Virtualization massively improves memory consumption and performance of large lists by
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* maintaining a finite render window of active items and replacing all items outside of the render
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* window with appropriately sized blank space. The window adapts to scrolling behavior, and items
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* are rendered incrementally with low-pri (after any running interactions) if they are far from the
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* visible area, or with hi-pri otherwise to minimize the potential of seeing blank space.
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*
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* Some caveats:
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*
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* - Internal state is not preserved when content scrolls out of the render window. Make sure all
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* your data is captured in the item data or external stores like Flux, Redux, or Relay.
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* - This is a `PureComponent` which means that it will not re-render if `props` remain shallow-
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* equal. Make sure that everything your `renderItem` function depends on is passed as a prop
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* (e.g. `extraData`) that is not `===` after updates, otherwise your UI may not update on
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* changes. This includes the `data` prop and parent component state.
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* - In order to constrain memory and enable smooth scrolling, content is rendered asynchronously
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* offscreen. This means it's possible to scroll faster than the fill rate ands momentarily see
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* blank content. This is a tradeoff that can be adjusted to suit the needs of each application,
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* and we are working on improving it behind the scenes.
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* - By default, the list looks for a `key` prop on each item and uses that for the React key.
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* Alternatively, you can provide a custom `keyExtractor` prop.
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*
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*/
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class VirtualizedList extends React.PureComponent<Props, State> {
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props: Props;
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// scrollToEnd may be janky without getItemLayout prop
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scrollToEnd(params?: ?{animated?: ?boolean}) {
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const animated = params ? params.animated : true;
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const veryLast = this.props.getItemCount(this.props.data) - 1;
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const frame = this._getFrameMetricsApprox(veryLast);
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const offset = Math.max(
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0,
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frame.offset +
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frame.length +
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this._footerLength -
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this._scrollMetrics.visibleLength,
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);
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found when
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* upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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this._scrollRef.scrollTo(
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found
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* when upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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this.props.horizontal ? {x: offset, animated} : {y: offset, animated},
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);
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}
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// scrollToIndex may be janky without getItemLayout prop
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scrollToIndex(params: {
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animated?: ?boolean,
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index: number,
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viewOffset?: number,
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viewPosition?: number,
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}) {
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const {data, horizontal, getItemCount, getItemLayout} = this.props;
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const {animated, index, viewOffset, viewPosition} = params;
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invariant(
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index >= 0 && index < getItemCount(data),
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`scrollToIndex out of range: ${index} vs ${getItemCount(data) - 1}`,
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);
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invariant(
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getItemLayout || index <= this._highestMeasuredFrameIndex,
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'scrollToIndex should be used in conjunction with getItemLayout, ' +
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'otherwise there is no way to know the location of an arbitrary index.',
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);
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const frame = this._getFrameMetricsApprox(index);
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const offset =
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Math.max(
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0,
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frame.offset -
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(viewPosition || 0) *
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(this._scrollMetrics.visibleLength - frame.length),
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) - (viewOffset || 0);
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found when
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* upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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this._scrollRef.scrollTo(
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found
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* when upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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horizontal ? {x: offset, animated} : {y: offset, animated},
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);
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}
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// scrollToItem may be janky without getItemLayout prop. Required linear scan through items -
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// use scrollToIndex instead if possible.
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scrollToItem(params: {
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animated?: ?boolean,
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item: Item,
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viewPosition?: number,
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}) {
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const {item} = params;
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const {data, getItem, getItemCount} = this.props;
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const itemCount = getItemCount(data);
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for (let index = 0; index < itemCount; index++) {
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if (getItem(data, index) === item) {
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this.scrollToIndex({...params, index});
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break;
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}
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}
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}
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/**
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* Scroll to a specific content pixel offset in the list.
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*
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* Param `offset` expects the offset to scroll to.
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* In case of `horizontal` is true, the offset is the x-value,
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* in any other case the offset is the y-value.
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*
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* Param `animated` (`true` by default) defines whether the list
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* should do an animation while scrolling.
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*/
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scrollToOffset(params: {animated?: ?boolean, offset: number}) {
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const {animated, offset} = params;
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found when
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* upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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this._scrollRef.scrollTo(
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found
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* when upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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this.props.horizontal ? {x: offset, animated} : {y: offset, animated},
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);
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}
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recordInteraction() {
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this._viewabilityHelper.recordInteraction();
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this._updateViewableItems(this.props.data);
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}
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flashScrollIndicators() {
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found when
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* upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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this._scrollRef.flashScrollIndicators();
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}
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/**
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* Provides a handle to the underlying scroll responder.
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* Note that `this._scrollRef` might not be a `ScrollView`, so we
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* need to check that it responds to `getScrollResponder` before calling it.
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*/
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getScrollResponder() {
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if (this._scrollRef && this._scrollRef.getScrollResponder) {
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found
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* when upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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return this._scrollRef.getScrollResponder();
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}
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}
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getScrollableNode() {
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if (this._scrollRef && this._scrollRef.getScrollableNode) {
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found
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* when upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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return this._scrollRef.getScrollableNode();
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} else {
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return ReactNative.findNodeHandle(this._scrollRef);
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}
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}
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setNativeProps(props: Object) {
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if (this._scrollRef) {
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/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
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* error when upgrading Flow's support for React. Common errors found
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* when upgrading Flow's React support are documented at
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* https://fburl.com/eq7bs81w */
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this._scrollRef.setNativeProps(props);
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}
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}
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static defaultProps = {
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disableVirtualization: false,
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horizontal: false,
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initialNumToRender: 10,
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keyExtractor: (item: Item, index: number) => {
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if (item.key != null) {
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return item.key;
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}
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_usedIndexForKey = true;
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return String(index);
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},
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maxToRenderPerBatch: 10,
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onEndReachedThreshold: 2, // multiples of length
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scrollEventThrottle: 50,
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updateCellsBatchingPeriod: 50,
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windowSize: 21, // multiples of length
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};
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static contextTypes = {
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virtualizedList: PropTypes.shape({
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horizontal: PropTypes.bool,
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}),
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};
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static childContextTypes = {
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virtualizedList: PropTypes.shape({
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horizontal: PropTypes.bool,
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}),
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};
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getChildContext() {
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return {
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virtualizedList: {
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horizontal: this.props.horizontal,
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// TODO: support nested virtualization and onViewableItemsChanged
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},
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};
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}
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state: State;
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constructor(props: Props, context: Object) {
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super(props, context);
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invariant(
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!props.onScroll || !props.onScroll.__isNative,
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'Components based on VirtualizedList must be wrapped with Animated.createAnimatedComponent ' +
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'to support native onScroll events with useNativeDriver',
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);
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invariant(
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!(this._isNestedWithSameOrientation() && props.onViewableItemsChanged),
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'Nesting lists that scroll in the same direction does not support onViewableItemsChanged' +
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'on the inner list.',
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);
|
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this._fillRateHelper = new FillRateHelper(this._getFrameMetrics);
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this._updateCellsToRenderBatcher = new Batchinator(
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this._updateCellsToRender,
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this.props.updateCellsBatchingPeriod,
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);
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this._viewabilityHelper = new ViewabilityHelper(
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this.props.viewabilityConfig,
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);
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this.state = {
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first: this.props.initialScrollIndex || 0,
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last:
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Math.min(
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this.props.getItemCount(this.props.data),
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(this.props.initialScrollIndex || 0) + this.props.initialNumToRender,
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) - 1,
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};
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}
|
|
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componentDidMount() {
|
|
if (this.props.initialScrollIndex) {
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this._initialScrollIndexTimeout = setTimeout(
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() =>
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this.scrollToIndex({
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animated: false,
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index: this.props.initialScrollIndex,
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}),
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0,
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);
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}
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}
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componentWillUnmount() {
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this._updateViewableItems(null);
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this._updateCellsToRenderBatcher.dispose();
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this._viewabilityHelper.dispose();
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this._fillRateHelper.deactivateAndFlush();
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clearTimeout(this._initialScrollIndexTimeout);
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}
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componentWillReceiveProps(newProps: Props) {
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const {data, extraData, getItemCount, maxToRenderPerBatch} = newProps;
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// first and last could be stale (e.g. if a new, shorter items props is passed in), so we make
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// sure we're rendering a reasonable range here.
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this.setState({
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first: Math.max(
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0,
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Math.min(
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this.state.first,
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getItemCount(data) - 1 - maxToRenderPerBatch,
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),
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),
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last: Math.max(0, Math.min(this.state.last, getItemCount(data) - 1)),
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});
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if (data !== this.props.data || extraData !== this.props.extraData) {
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this._hasDataChangedSinceEndReached = true;
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}
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}
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_pushCells(
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cells: Array<Object>,
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stickyHeaderIndices: Array<number>,
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stickyIndicesFromProps: Set<number>,
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first: number,
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last: number,
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inversionStyle: ?StyleObj,
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) {
|
|
const {
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CellRendererComponent,
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ItemSeparatorComponent,
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|
data,
|
|
getItem,
|
|
getItemCount,
|
|
keyExtractor,
|
|
} = this.props;
|
|
const stickyOffset = this.props.ListHeaderComponent ? 1 : 0;
|
|
const end = getItemCount(data) - 1;
|
|
let prevCellKey;
|
|
last = Math.min(end, last);
|
|
for (let ii = first; ii <= last; ii++) {
|
|
const item = getItem(data, ii);
|
|
invariant(item, 'No item for index ' + ii);
|
|
const key = keyExtractor(item, ii);
|
|
if (stickyIndicesFromProps.has(ii + stickyOffset)) {
|
|
stickyHeaderIndices.push(cells.length);
|
|
}
|
|
cells.push(
|
|
<CellRenderer
|
|
CellRendererComponent={CellRendererComponent}
|
|
ItemSeparatorComponent={ii < end ? ItemSeparatorComponent : undefined}
|
|
cellKey={key}
|
|
fillRateHelper={this._fillRateHelper}
|
|
index={ii}
|
|
inversionStyle={inversionStyle}
|
|
item={item}
|
|
key={key}
|
|
prevCellKey={prevCellKey}
|
|
onUpdateSeparators={this._onUpdateSeparators}
|
|
onLayout={e => this._onCellLayout(e, key, ii)}
|
|
onUnmount={this._onCellUnmount}
|
|
parentProps={this.props}
|
|
ref={ref => {
|
|
this._cellRefs[key] = ref;
|
|
}}
|
|
/>,
|
|
);
|
|
prevCellKey = key;
|
|
}
|
|
}
|
|
|
|
_onUpdateSeparators = (keys: Array<?string>, newProps: Object) => {
|
|
keys.forEach(key => {
|
|
const ref = key != null && this._cellRefs[key];
|
|
ref && ref.updateSeparatorProps(newProps);
|
|
});
|
|
};
|
|
|
|
_isVirtualizationDisabled(): boolean {
|
|
return (
|
|
this.props.disableVirtualization || this._isNestedWithSameOrientation()
|
|
);
|
|
}
|
|
|
|
_isNestedWithSameOrientation(): boolean {
|
|
const nestedContext = this.context.virtualizedList;
|
|
return !!(
|
|
nestedContext && !!nestedContext.horizontal === !!this.props.horizontal
|
|
);
|
|
}
|
|
|
|
render() {
|
|
if (__DEV__) {
|
|
const flatStyles = flattenStyle(this.props.contentContainerStyle);
|
|
warning(
|
|
flatStyles == null || flatStyles.flexWrap !== 'wrap',
|
|
'`flexWrap: `wrap`` is not supported with the `VirtualizedList` components.' +
|
|
'Consider using `numColumns` with `FlatList` instead.',
|
|
);
|
|
}
|
|
|
|
const {
|
|
ListEmptyComponent,
|
|
ListFooterComponent,
|
|
ListHeaderComponent,
|
|
} = this.props;
|
|
const {data, horizontal} = this.props;
|
|
const isVirtualizationDisabled = this._isVirtualizationDisabled();
|
|
const inversionStyle = this.props.inverted
|
|
? this.props.horizontal
|
|
? styles.horizontallyInverted
|
|
: styles.verticallyInverted
|
|
: null;
|
|
const cells = [];
|
|
const stickyIndicesFromProps = new Set(this.props.stickyHeaderIndices);
|
|
const stickyHeaderIndices = [];
|
|
if (ListHeaderComponent) {
|
|
const element = React.isValidElement(ListHeaderComponent)
|
|
? ListHeaderComponent // $FlowFixMe
|
|
: <ListHeaderComponent />;
|
|
cells.push(
|
|
/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
|
|
* error when upgrading Flow's support for React. Common errors found
|
|
* when upgrading Flow's React support are documented at
|
|
* https://fburl.com/eq7bs81w */
|
|
<View
|
|
key="$header"
|
|
onLayout={this._onLayoutHeader}
|
|
style={inversionStyle}>
|
|
{element}
|
|
</View>,
|
|
);
|
|
}
|
|
const itemCount = this.props.getItemCount(data);
|
|
if (itemCount > 0) {
|
|
_usedIndexForKey = false;
|
|
const spacerKey = !horizontal ? 'height' : 'width';
|
|
const lastInitialIndex = this.props.initialScrollIndex
|
|
? -1
|
|
: this.props.initialNumToRender - 1;
|
|
const {first, last} = this.state;
|
|
this._pushCells(
|
|
cells,
|
|
stickyHeaderIndices,
|
|
stickyIndicesFromProps,
|
|
0,
|
|
lastInitialIndex,
|
|
inversionStyle,
|
|
);
|
|
const firstAfterInitial = Math.max(lastInitialIndex + 1, first);
|
|
if (!isVirtualizationDisabled && first > lastInitialIndex + 1) {
|
|
let insertedStickySpacer = false;
|
|
if (stickyIndicesFromProps.size > 0) {
|
|
const stickyOffset = ListHeaderComponent ? 1 : 0;
|
|
// See if there are any sticky headers in the virtualized space that we need to render.
|
|
for (let ii = firstAfterInitial - 1; ii > lastInitialIndex; ii--) {
|
|
if (stickyIndicesFromProps.has(ii + stickyOffset)) {
|
|
const initBlock = this._getFrameMetricsApprox(lastInitialIndex);
|
|
const stickyBlock = this._getFrameMetricsApprox(ii);
|
|
const leadSpace =
|
|
stickyBlock.offset - (initBlock.offset + initBlock.length);
|
|
cells.push(
|
|
<View key="$sticky_lead" style={{[spacerKey]: leadSpace}} />,
|
|
);
|
|
this._pushCells(
|
|
cells,
|
|
stickyHeaderIndices,
|
|
stickyIndicesFromProps,
|
|
ii,
|
|
ii,
|
|
inversionStyle,
|
|
);
|
|
const trailSpace =
|
|
this._getFrameMetricsApprox(first).offset -
|
|
(stickyBlock.offset + stickyBlock.length);
|
|
cells.push(
|
|
<View key="$sticky_trail" style={{[spacerKey]: trailSpace}} />,
|
|
);
|
|
insertedStickySpacer = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (!insertedStickySpacer) {
|
|
const initBlock = this._getFrameMetricsApprox(lastInitialIndex);
|
|
const firstSpace =
|
|
this._getFrameMetricsApprox(first).offset -
|
|
(initBlock.offset + initBlock.length);
|
|
cells.push(
|
|
<View key="$lead_spacer" style={{[spacerKey]: firstSpace}} />,
|
|
);
|
|
}
|
|
}
|
|
this._pushCells(
|
|
cells,
|
|
stickyHeaderIndices,
|
|
stickyIndicesFromProps,
|
|
firstAfterInitial,
|
|
last,
|
|
inversionStyle,
|
|
);
|
|
if (!this._hasWarned.keys && _usedIndexForKey) {
|
|
console.warn(
|
|
'VirtualizedList: missing keys for items, make sure to specify a key property on each ' +
|
|
'item or provide a custom keyExtractor.',
|
|
);
|
|
this._hasWarned.keys = true;
|
|
}
|
|
if (!isVirtualizationDisabled && last < itemCount - 1) {
|
|
const lastFrame = this._getFrameMetricsApprox(last);
|
|
// Without getItemLayout, we limit our tail spacer to the _highestMeasuredFrameIndex to
|
|
// prevent the user for hyperscrolling into un-measured area because otherwise content will
|
|
// likely jump around as it renders in above the viewport.
|
|
const end = this.props.getItemLayout
|
|
? itemCount - 1
|
|
: Math.min(itemCount - 1, this._highestMeasuredFrameIndex);
|
|
const endFrame = this._getFrameMetricsApprox(end);
|
|
const tailSpacerLength =
|
|
endFrame.offset +
|
|
endFrame.length -
|
|
(lastFrame.offset + lastFrame.length);
|
|
cells.push(
|
|
<View key="$tail_spacer" style={{[spacerKey]: tailSpacerLength}} />,
|
|
);
|
|
}
|
|
} else if (ListEmptyComponent) {
|
|
const element = React.isValidElement(ListEmptyComponent)
|
|
? ListEmptyComponent // $FlowFixMe
|
|
: <ListEmptyComponent />;
|
|
cells.push(
|
|
/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
|
|
* error when upgrading Flow's support for React. Common errors found
|
|
* when upgrading Flow's React support are documented at
|
|
* https://fburl.com/eq7bs81w */
|
|
<View
|
|
key="$empty"
|
|
onLayout={this._onLayoutEmpty}
|
|
style={inversionStyle}>
|
|
{element}
|
|
</View>,
|
|
);
|
|
}
|
|
if (ListFooterComponent) {
|
|
const element = React.isValidElement(ListFooterComponent)
|
|
? ListFooterComponent // $FlowFixMe
|
|
: <ListFooterComponent />;
|
|
cells.push(
|
|
/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
|
|
* error when upgrading Flow's support for React. Common errors found
|
|
* when upgrading Flow's React support are documented at
|
|
* https://fburl.com/eq7bs81w */
|
|
<View
|
|
key="$footer"
|
|
onLayout={this._onLayoutFooter}
|
|
style={inversionStyle}>
|
|
{element}
|
|
</View>,
|
|
);
|
|
}
|
|
const scrollProps = {
|
|
...this.props,
|
|
onContentSizeChange: this._onContentSizeChange,
|
|
onLayout: this._onLayout,
|
|
onScroll: this._onScroll,
|
|
onScrollBeginDrag: this._onScrollBeginDrag,
|
|
onScrollEndDrag: this._onScrollEndDrag,
|
|
onMomentumScrollEnd: this._onMomentumScrollEnd,
|
|
scrollEventThrottle: this.props.scrollEventThrottle, // TODO: Android support
|
|
stickyHeaderIndices,
|
|
};
|
|
if (inversionStyle) {
|
|
scrollProps.style = [inversionStyle, this.props.style];
|
|
}
|
|
const ret = React.cloneElement(
|
|
(this.props.renderScrollComponent || this._defaultRenderScrollComponent)(
|
|
scrollProps,
|
|
),
|
|
{
|
|
ref: this._captureScrollRef,
|
|
},
|
|
cells,
|
|
);
|
|
if (this.props.debug) {
|
|
return (
|
|
<View style={{flex: 1}}>
|
|
{ret}
|
|
{this._renderDebugOverlay()}
|
|
</View>
|
|
);
|
|
} else {
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
componentDidUpdate() {
|
|
this._scheduleCellsToRenderUpdate();
|
|
}
|
|
|
|
_averageCellLength = 0;
|
|
_cellRefs = {};
|
|
_hasDataChangedSinceEndReached = true;
|
|
_hasWarned = {};
|
|
_highestMeasuredFrameIndex = 0;
|
|
_headerLength = 0;
|
|
_initialScrollIndexTimeout = 0;
|
|
_fillRateHelper: FillRateHelper;
|
|
_frames = {};
|
|
_footerLength = 0;
|
|
_scrollMetrics = {
|
|
contentLength: 0,
|
|
dOffset: 0,
|
|
dt: 10,
|
|
offset: 0,
|
|
timestamp: 0,
|
|
velocity: 0,
|
|
visibleLength: 0,
|
|
};
|
|
_scrollRef = (null: any);
|
|
_sentEndForContentLength = 0;
|
|
_totalCellLength = 0;
|
|
_totalCellsMeasured = 0;
|
|
_updateCellsToRenderBatcher: Batchinator;
|
|
_viewabilityHelper: ViewabilityHelper;
|
|
|
|
_captureScrollRef = ref => {
|
|
this._scrollRef = ref;
|
|
};
|
|
|
|
_computeBlankness() {
|
|
this._fillRateHelper.computeBlankness(
|
|
this.props,
|
|
this.state,
|
|
this._scrollMetrics,
|
|
);
|
|
}
|
|
|
|
_defaultRenderScrollComponent = props => {
|
|
if (this._isNestedWithSameOrientation()) {
|
|
return <View {...props} />;
|
|
} else if (props.onRefresh) {
|
|
invariant(
|
|
typeof props.refreshing === 'boolean',
|
|
'`refreshing` prop must be set as a boolean in order to use `onRefresh`, but got `' +
|
|
JSON.stringify(props.refreshing) +
|
|
'`',
|
|
);
|
|
return (
|
|
/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
|
|
* error found when Flow v0.53 was deployed. To see the error delete
|
|
* this comment and run Flow. */
|
|
<ScrollView
|
|
{...props}
|
|
refreshControl={
|
|
/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment
|
|
* suppresses an error found when Flow v0.53 was deployed. To see
|
|
* the error delete this comment and run Flow. */
|
|
<RefreshControl
|
|
refreshing={props.refreshing}
|
|
onRefresh={props.onRefresh}
|
|
progressViewOffset={props.progressViewOffset}
|
|
/>
|
|
}
|
|
/>
|
|
);
|
|
} else {
|
|
/* $FlowFixMe(>=0.53.0 site=react_native_fb) This comment suppresses an
|
|
* error found when Flow v0.53 was deployed. To see the error delete this
|
|
* comment and run Flow. */
|
|
return <ScrollView {...props} />;
|
|
}
|
|
};
|
|
|
|
_onCellLayout(e, cellKey, index) {
|
|
const layout = e.nativeEvent.layout;
|
|
const next = {
|
|
offset: this._selectOffset(layout),
|
|
length: this._selectLength(layout),
|
|
index,
|
|
inLayout: true,
|
|
};
|
|
const curr = this._frames[cellKey];
|
|
if (
|
|
!curr ||
|
|
next.offset !== curr.offset ||
|
|
next.length !== curr.length ||
|
|
index !== curr.index
|
|
) {
|
|
this._totalCellLength += next.length - (curr ? curr.length : 0);
|
|
this._totalCellsMeasured += curr ? 0 : 1;
|
|
this._averageCellLength =
|
|
this._totalCellLength / this._totalCellsMeasured;
|
|
this._frames[cellKey] = next;
|
|
this._highestMeasuredFrameIndex = Math.max(
|
|
this._highestMeasuredFrameIndex,
|
|
index,
|
|
);
|
|
this._scheduleCellsToRenderUpdate();
|
|
} else {
|
|
this._frames[cellKey].inLayout = true;
|
|
}
|
|
this._computeBlankness();
|
|
}
|
|
|
|
_onCellUnmount = (cellKey: string) => {
|
|
const curr = this._frames[cellKey];
|
|
if (curr) {
|
|
this._frames[cellKey] = {...curr, inLayout: false};
|
|
}
|
|
};
|
|
|
|
_onLayout = (e: Object) => {
|
|
this._scrollMetrics.visibleLength = this._selectLength(
|
|
e.nativeEvent.layout,
|
|
);
|
|
this.props.onLayout && this.props.onLayout(e);
|
|
this._scheduleCellsToRenderUpdate();
|
|
this._maybeCallOnEndReached();
|
|
};
|
|
|
|
_onLayoutEmpty = e => {
|
|
this.props.onLayout && this.props.onLayout(e);
|
|
};
|
|
|
|
_onLayoutFooter = e => {
|
|
this._footerLength = this._selectLength(e.nativeEvent.layout);
|
|
};
|
|
|
|
_onLayoutHeader = e => {
|
|
this._headerLength = this._selectLength(e.nativeEvent.layout);
|
|
};
|
|
|
|
_renderDebugOverlay() {
|
|
const normalize =
|
|
this._scrollMetrics.visibleLength / this._scrollMetrics.contentLength;
|
|
const framesInLayout = [];
|
|
const itemCount = this.props.getItemCount(this.props.data);
|
|
for (let ii = 0; ii < itemCount; ii++) {
|
|
const frame = this._getFrameMetricsApprox(ii);
|
|
if (frame.inLayout) {
|
|
framesInLayout.push(frame);
|
|
}
|
|
}
|
|
const windowTop = this._getFrameMetricsApprox(this.state.first).offset;
|
|
const frameLast = this._getFrameMetricsApprox(this.state.last);
|
|
const windowLen = frameLast.offset + frameLast.length - windowTop;
|
|
const visTop = this._scrollMetrics.offset;
|
|
const visLen = this._scrollMetrics.visibleLength;
|
|
const baseStyle = {position: 'absolute', top: 0, right: 0};
|
|
return (
|
|
<View
|
|
style={{
|
|
...baseStyle,
|
|
bottom: 0,
|
|
width: 20,
|
|
borderColor: 'blue',
|
|
borderWidth: 1,
|
|
}}>
|
|
{framesInLayout.map((f, ii) =>
|
|
<View
|
|
key={'f' + ii}
|
|
style={{
|
|
...baseStyle,
|
|
left: 0,
|
|
top: f.offset * normalize,
|
|
height: f.length * normalize,
|
|
backgroundColor: 'orange',
|
|
}}
|
|
/>,
|
|
)}
|
|
<View
|
|
style={{
|
|
...baseStyle,
|
|
left: 0,
|
|
top: windowTop * normalize,
|
|
height: windowLen * normalize,
|
|
borderColor: 'green',
|
|
borderWidth: 2,
|
|
}}
|
|
/>
|
|
<View
|
|
style={{
|
|
...baseStyle,
|
|
left: 0,
|
|
top: visTop * normalize,
|
|
height: visLen * normalize,
|
|
borderColor: 'red',
|
|
borderWidth: 2,
|
|
}}
|
|
/>
|
|
</View>
|
|
);
|
|
}
|
|
|
|
_selectLength(metrics: {height: number, width: number}): number {
|
|
return !this.props.horizontal ? metrics.height : metrics.width;
|
|
}
|
|
|
|
_selectOffset(metrics: {x: number, y: number}): number {
|
|
return !this.props.horizontal ? metrics.y : metrics.x;
|
|
}
|
|
|
|
_maybeCallOnEndReached() {
|
|
const {
|
|
data,
|
|
getItemCount,
|
|
onEndReached,
|
|
onEndReachedThreshold,
|
|
} = this.props;
|
|
const {contentLength, visibleLength, offset} = this._scrollMetrics;
|
|
const distanceFromEnd = contentLength - visibleLength - offset;
|
|
if (
|
|
onEndReached &&
|
|
this.state.last === getItemCount(data) - 1 &&
|
|
distanceFromEnd < onEndReachedThreshold * visibleLength &&
|
|
(this._hasDataChangedSinceEndReached ||
|
|
this._scrollMetrics.contentLength !== this._sentEndForContentLength)
|
|
) {
|
|
// Only call onEndReached once for a given dataset + content length.
|
|
this._hasDataChangedSinceEndReached = false;
|
|
this._sentEndForContentLength = this._scrollMetrics.contentLength;
|
|
onEndReached({distanceFromEnd});
|
|
}
|
|
}
|
|
|
|
_onContentSizeChange = (width: number, height: number) => {
|
|
if (this.props.onContentSizeChange) {
|
|
this.props.onContentSizeChange(width, height);
|
|
}
|
|
this._scrollMetrics.contentLength = this._selectLength({height, width});
|
|
this._scheduleCellsToRenderUpdate();
|
|
this._maybeCallOnEndReached();
|
|
};
|
|
|
|
_onScroll = (e: Object) => {
|
|
if (this.props.onScroll) {
|
|
this.props.onScroll(e);
|
|
}
|
|
const timestamp = e.timeStamp;
|
|
const visibleLength = this._selectLength(e.nativeEvent.layoutMeasurement);
|
|
const contentLength = this._selectLength(e.nativeEvent.contentSize);
|
|
const offset = this._selectOffset(e.nativeEvent.contentOffset);
|
|
const dt = this._scrollMetrics.timestamp
|
|
? Math.max(1, timestamp - this._scrollMetrics.timestamp)
|
|
: 1;
|
|
if (
|
|
dt > 500 &&
|
|
this._scrollMetrics.dt > 500 &&
|
|
contentLength > 5 * visibleLength &&
|
|
!this._hasWarned.perf
|
|
) {
|
|
infoLog(
|
|
'VirtualizedList: You have a large list that is slow to update - make sure your ' +
|
|
'renderItem function renders components that follow React performance best practices ' +
|
|
'like PureComponent, shouldComponentUpdate, etc.',
|
|
{dt, prevDt: this._scrollMetrics.dt, contentLength},
|
|
);
|
|
this._hasWarned.perf = true;
|
|
}
|
|
const dOffset = offset - this._scrollMetrics.offset;
|
|
const velocity = dOffset / dt;
|
|
this._scrollMetrics = {
|
|
contentLength,
|
|
dt,
|
|
dOffset,
|
|
offset,
|
|
timestamp,
|
|
velocity,
|
|
visibleLength,
|
|
};
|
|
this._updateViewableItems(this.props.data);
|
|
if (!this.props) {
|
|
return;
|
|
}
|
|
this._maybeCallOnEndReached();
|
|
if (velocity !== 0) {
|
|
this._fillRateHelper.activate();
|
|
}
|
|
this._computeBlankness();
|
|
this._scheduleCellsToRenderUpdate();
|
|
};
|
|
|
|
_scheduleCellsToRenderUpdate() {
|
|
const {first, last} = this.state;
|
|
const {offset, visibleLength, velocity} = this._scrollMetrics;
|
|
const itemCount = this.props.getItemCount(this.props.data);
|
|
let hiPri = false;
|
|
if (first > 0 || last < itemCount - 1) {
|
|
const distTop = offset - this._getFrameMetricsApprox(first).offset;
|
|
const distBottom =
|
|
this._getFrameMetricsApprox(last).offset - (offset + visibleLength);
|
|
const scrollingThreshold =
|
|
this.props.onEndReachedThreshold * visibleLength / 2;
|
|
hiPri =
|
|
Math.min(distTop, distBottom) < 0 ||
|
|
(velocity < -2 && distTop < scrollingThreshold) ||
|
|
(velocity > 2 && distBottom < scrollingThreshold);
|
|
}
|
|
// Only trigger high-priority updates if we've actually rendered cells,
|
|
// and with that size estimate, accurately compute how many cells we should render.
|
|
// Otherwise, it would just render as many cells as it can (of zero dimension),
|
|
// each time through attempting to render more (limited by maxToRenderPerBatch),
|
|
// starving the renderer from actually laying out the objects and computing _averageCellLength.
|
|
if (hiPri && this._averageCellLength) {
|
|
// Don't worry about interactions when scrolling quickly; focus on filling content as fast
|
|
// as possible.
|
|
this._updateCellsToRenderBatcher.dispose({abort: true});
|
|
this._updateCellsToRender();
|
|
return;
|
|
} else {
|
|
this._updateCellsToRenderBatcher.schedule();
|
|
}
|
|
}
|
|
|
|
_onScrollBeginDrag = (e): void => {
|
|
this._viewabilityHelper.recordInteraction();
|
|
this.props.onScrollBeginDrag && this.props.onScrollBeginDrag(e);
|
|
};
|
|
|
|
_onScrollEndDrag = (e): void => {
|
|
const {velocity} = e.nativeEvent;
|
|
if (velocity) {
|
|
this._scrollMetrics.velocity = this._selectOffset(velocity);
|
|
}
|
|
this._computeBlankness();
|
|
this.props.onScrollEndDrag && this.props.onScrollEndDrag(e);
|
|
};
|
|
|
|
_onMomentumScrollEnd = (e): void => {
|
|
this._scrollMetrics.velocity = 0;
|
|
this._computeBlankness();
|
|
this.props.onMomentumScrollEnd && this.props.onMomentumScrollEnd(e);
|
|
};
|
|
|
|
_updateCellsToRender = () => {
|
|
const {data, getItemCount, onEndReachedThreshold} = this.props;
|
|
const isVirtualizationDisabled = this._isVirtualizationDisabled();
|
|
this._updateViewableItems(data);
|
|
if (!data) {
|
|
return;
|
|
}
|
|
this.setState(state => {
|
|
let newState;
|
|
if (!isVirtualizationDisabled) {
|
|
// If we run this with bogus data, we'll force-render window {first: 0, last: 0},
|
|
// and wipe out the initialNumToRender rendered elements.
|
|
// So let's wait until the scroll view metrics have been set up. And until then,
|
|
// we will trust the initialNumToRender suggestion
|
|
if (this._scrollMetrics.visibleLength) {
|
|
// If we have a non-zero initialScrollIndex and run this before we've scrolled,
|
|
// we'll wipe out the initialNumToRender rendered elements starting at initialScrollIndex.
|
|
// So let's wait until we've scrolled the view to the right place. And until then,
|
|
// we will trust the initialScrollIndex suggestion.
|
|
if (!this.props.initialScrollIndex || this._scrollMetrics.offset) {
|
|
newState = computeWindowedRenderLimits(
|
|
this.props,
|
|
state,
|
|
this._getFrameMetricsApprox,
|
|
this._scrollMetrics,
|
|
);
|
|
}
|
|
}
|
|
} else {
|
|
const {contentLength, offset, visibleLength} = this._scrollMetrics;
|
|
const distanceFromEnd = contentLength - visibleLength - offset;
|
|
const renderAhead =
|
|
distanceFromEnd < onEndReachedThreshold * visibleLength
|
|
? this.props.maxToRenderPerBatch
|
|
: 0;
|
|
newState = {
|
|
first: 0,
|
|
last: Math.min(state.last + renderAhead, getItemCount(data) - 1),
|
|
};
|
|
}
|
|
return newState;
|
|
});
|
|
};
|
|
|
|
_createViewToken = (index: number, isViewable: boolean) => {
|
|
const {data, getItem, keyExtractor} = this.props;
|
|
const item = getItem(data, index);
|
|
invariant(item, 'Missing item for index ' + index);
|
|
return {index, item, key: keyExtractor(item, index), isViewable};
|
|
};
|
|
|
|
_getFrameMetricsApprox = (
|
|
index: number,
|
|
): {length: number, offset: number} => {
|
|
const frame = this._getFrameMetrics(index);
|
|
if (frame && frame.index === index) {
|
|
// check for invalid frames due to row re-ordering
|
|
return frame;
|
|
} else {
|
|
const {getItemLayout} = this.props;
|
|
invariant(
|
|
!getItemLayout,
|
|
'Should not have to estimate frames when a measurement metrics function is provided',
|
|
);
|
|
return {
|
|
length: this._averageCellLength,
|
|
offset: this._averageCellLength * index,
|
|
};
|
|
}
|
|
};
|
|
|
|
_getFrameMetrics = (
|
|
index: number,
|
|
): ?{
|
|
length: number,
|
|
offset: number,
|
|
index: number,
|
|
inLayout?: boolean,
|
|
} => {
|
|
const {
|
|
data,
|
|
getItem,
|
|
getItemCount,
|
|
getItemLayout,
|
|
keyExtractor,
|
|
} = this.props;
|
|
invariant(
|
|
getItemCount(data) > index,
|
|
'Tried to get frame for out of range index ' + index,
|
|
);
|
|
const item = getItem(data, index);
|
|
let frame = item && this._frames[keyExtractor(item, index)];
|
|
if (!frame || frame.index !== index) {
|
|
if (getItemLayout) {
|
|
frame = getItemLayout(data, index);
|
|
if (__DEV__) {
|
|
const frameType = PropTypes.shape({
|
|
length: PropTypes.number.isRequired,
|
|
offset: PropTypes.number.isRequired,
|
|
index: PropTypes.number.isRequired,
|
|
}).isRequired;
|
|
PropTypes.checkPropTypes(
|
|
{frame: frameType},
|
|
{frame},
|
|
'frame',
|
|
'VirtualizedList.getItemLayout',
|
|
);
|
|
}
|
|
}
|
|
}
|
|
return frame;
|
|
};
|
|
|
|
_updateViewableItems(data: any) {
|
|
const {getItemCount, onViewableItemsChanged} = this.props;
|
|
if (!onViewableItemsChanged) {
|
|
return;
|
|
}
|
|
this._viewabilityHelper.onUpdate(
|
|
getItemCount(data),
|
|
this._scrollMetrics.offset,
|
|
this._scrollMetrics.visibleLength,
|
|
this._getFrameMetrics,
|
|
this._createViewToken,
|
|
onViewableItemsChanged,
|
|
this.state,
|
|
);
|
|
}
|
|
}
|
|
|
|
class CellRenderer extends React.Component<{
|
|
CellRendererComponent?: ?React.ComponentType<any>,
|
|
ItemSeparatorComponent: ?React.ComponentType<*>,
|
|
cellKey: string,
|
|
fillRateHelper: FillRateHelper,
|
|
index: number,
|
|
inversionStyle: ?StyleObj,
|
|
item: Item,
|
|
onLayout: (event: Object) => void, // This is extracted by ScrollViewStickyHeader
|
|
onUnmount: (cellKey: string) => void,
|
|
onUpdateSeparators: (cellKeys: Array<?string>, props: Object) => void,
|
|
parentProps: {
|
|
getItemLayout?: ?Function,
|
|
renderItem: renderItemType,
|
|
},
|
|
prevCellKey: ?string,
|
|
}, $FlowFixMeState> {
|
|
state = {
|
|
separatorProps: {
|
|
highlighted: false,
|
|
leadingItem: this.props.item,
|
|
},
|
|
};
|
|
|
|
// TODO: consider factoring separator stuff out of VirtualizedList into FlatList since it's not
|
|
// reused by SectionList and we can keep VirtualizedList simpler.
|
|
_separators = {
|
|
highlight: () => {
|
|
const {cellKey, prevCellKey} = this.props;
|
|
this.props.onUpdateSeparators([cellKey, prevCellKey], {
|
|
highlighted: true,
|
|
});
|
|
},
|
|
unhighlight: () => {
|
|
const {cellKey, prevCellKey} = this.props;
|
|
this.props.onUpdateSeparators([cellKey, prevCellKey], {
|
|
highlighted: false,
|
|
});
|
|
},
|
|
updateProps: (select: 'leading' | 'trailing', newProps: Object) => {
|
|
const {cellKey, prevCellKey} = this.props;
|
|
this.props.onUpdateSeparators(
|
|
[select === 'leading' ? prevCellKey : cellKey],
|
|
newProps,
|
|
);
|
|
},
|
|
};
|
|
|
|
updateSeparatorProps(newProps: Object) {
|
|
this.setState(state => ({
|
|
separatorProps: {...state.separatorProps, ...newProps},
|
|
}));
|
|
}
|
|
|
|
componentWillUnmount() {
|
|
this.props.onUnmount(this.props.cellKey);
|
|
}
|
|
|
|
render() {
|
|
const {
|
|
CellRendererComponent,
|
|
ItemSeparatorComponent,
|
|
fillRateHelper,
|
|
item,
|
|
index,
|
|
inversionStyle,
|
|
parentProps,
|
|
} = this.props;
|
|
const {renderItem, getItemLayout} = parentProps;
|
|
invariant(renderItem, 'no renderItem!');
|
|
const element = renderItem({
|
|
item,
|
|
index,
|
|
separators: this._separators,
|
|
});
|
|
const onLayout =
|
|
getItemLayout && !parentProps.debug && !fillRateHelper.enabled()
|
|
? undefined
|
|
: this.props.onLayout;
|
|
// NOTE: that when this is a sticky header, `onLayout` will get automatically extracted and
|
|
// called explicitly by `ScrollViewStickyHeader`.
|
|
const itemSeparator =
|
|
ItemSeparatorComponent &&
|
|
<ItemSeparatorComponent {...this.state.separatorProps} />;
|
|
if (!CellRendererComponent) {
|
|
return (
|
|
<View style={inversionStyle} onLayout={onLayout}>
|
|
{element}
|
|
{itemSeparator}
|
|
</View>
|
|
);
|
|
}
|
|
return (
|
|
<CellRendererComponent
|
|
{...this.props}
|
|
style={inversionStyle}
|
|
onLayout={onLayout}>
|
|
{element}
|
|
{itemSeparator}
|
|
</CellRendererComponent>
|
|
);
|
|
}
|
|
}
|
|
|
|
const styles = StyleSheet.create({
|
|
verticallyInverted: {
|
|
transform: [{scaleY: -1}],
|
|
},
|
|
horizontallyInverted: {
|
|
transform: [{scaleX: -1}],
|
|
},
|
|
});
|
|
|
|
module.exports = VirtualizedList;
|