react-native/Libraries/Lists/SectionList.js

334 lines
12 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule SectionList
* @flow
* @format
*/
'use strict';
const MetroListView = require('MetroListView');
const Platform = require('Platform');
const React = require('React');
const VirtualizedSectionList = require('VirtualizedSectionList');
import type {ViewToken} from 'ViewabilityHelper';
import type {Props as VirtualizedSectionListProps} from 'VirtualizedSectionList';
type Item = any;
type SectionBase<SectionItemT> = {
/**
* The data for rendering items in this section.
*/
data: $ReadOnlyArray<SectionItemT>,
/**
* Optional key to keep track of section re-ordering. If you don't plan on re-ordering sections,
* the array index will be used by default.
*/
key?: string,
// Optional props will override list-wide props just for this section.
renderItem?: ?(info: {
item: SectionItemT,
index: number,
section: SectionBase<SectionItemT>,
separators: {
highlight: () => void,
unhighlight: () => void,
updateProps: (select: 'leading' | 'trailing', newProps: Object) => void,
},
}) => ?React.Element<any>,
ItemSeparatorComponent?: ?ReactClass<any>,
keyExtractor?: (item: SectionItemT) => string,
// TODO: support more optional/override props
// onViewableItemsChanged?: ...
};
type RequiredProps<SectionT: SectionBase<any>> = {
/**
* The actual data to render, akin to the `data` prop in [`<FlatList>`](/react-native/docs/flatlist.html).
*
* General shape:
*
* sections: $ReadOnlyArray<{
* data: $ReadOnlyArray<SectionItem>,
* renderItem?: ({item: SectionItem, ...}) => ?React.Element<*>,
* ItemSeparatorComponent?: ?ReactClass<{highlighted: boolean, ...}>,
* }>
*/
sections: $ReadOnlyArray<SectionT>,
};
type OptionalProps<SectionT: SectionBase<any>> = {
/**
* Default renderer for every item in every section. Can be over-ridden on a per-section basis.
*/
renderItem: (info: {
item: Item,
index: number,
section: SectionT,
separators: {
highlight: () => void,
unhighlight: () => void,
updateProps: (select: 'leading' | 'trailing', newProps: Object) => void,
},
}) => ?React.Element<any>,
/**
* Rendered in between each item, but not at the top or bottom. By default, `highlighted`,
* `section`, and `[leading/trailing][Item/Separator]` props are provided. `renderItem` provides
* `separators.highlight`/`unhighlight` which will update the `highlighted` prop, but you can also
* add custom props with `separators.updateProps`.
*/
ItemSeparatorComponent?: ?ReactClass<any>,
/**
* Rendered at the very beginning of the list. Can be a React Component Class, a render function, or
* a rendered element.
*/
ListHeaderComponent?: ?(ReactClass<any> | React.Element<any>),
/**
* Rendered when the list is empty. Can be a React Component Class, a render function, or
* a rendered element.
*/
ListEmptyComponent?: ?(ReactClass<any> | React.Element<any>),
/**
* Rendered at the very end of the list. Can be a React Component Class, a render function, or
* a rendered element.
*/
ListFooterComponent?: ?(ReactClass<any> | React.Element<any>),
/**
* Rendered at the top and bottom of each section (note this is different from
* `ItemSeparatorComponent` which is only rendered between items). These are intended to separate
* sections from the headers above and below and typically have the same highlight response as
* `ItemSeparatorComponent`. Also receives `highlighted`, `[leading/trailing][Item/Separator]`,
* and any custom props from `separators.updateProps`.
*/
SectionSeparatorComponent?: ?ReactClass<any>,
/**
* A marker property for telling the list to re-render (since it implements `PureComponent`). If
* any of your `renderItem`, Header, Footer, etc. functions depend on anything outside of the
* `data` prop, stick it here and treat it immutably.
*/
extraData?: any,
/**
* How many items to render in the initial batch. This should be enough to fill the screen but not
* much more. Note these items will never be unmounted as part of the windowed rendering in order
* to improve perceived performance of scroll-to-top actions.
*/
initialNumToRender: number,
/**
* Reverses the direction of scroll. Uses scale transforms of -1.
*/
inverted?: ?boolean,
/**
* Used to extract a unique key for a given item at the specified index. Key is used for caching
* and as the react key to track item re-ordering. The default extractor checks item.key, then
* falls back to using the index, like react does. Note that this sets keys for each item, but
* each overall section still needs its own key.
*/
keyExtractor: (item: Item, index: number) => string,
/**
* Called once when the scroll position gets within `onEndReachedThreshold` of the rendered
* content.
*/
onEndReached?: ?(info: {distanceFromEnd: number}) => void,
/**
* How far from the end (in units of visible length of the list) the bottom edge of the
* list must be from the end of the content to trigger the `onEndReached` callback.
* Thus a value of 0.5 will trigger `onEndReached` when the end of the content is
* within half the visible length of the list.
*/
onEndReachedThreshold?: ?number,
/**
* If provided, a standard RefreshControl will be added for "Pull to Refresh" functionality. Make
* sure to also set the `refreshing` prop correctly.
*/
onRefresh?: ?() => void,
/**
* Called when the viewability of rows changes, as defined by the
* `viewabilityConfig` prop.
*/
onViewableItemsChanged?: ?(info: {
viewableItems: Array<ViewToken>,
changed: Array<ViewToken>,
}) => void,
/**
* Set this true while waiting for new data from a refresh.
*/
refreshing?: ?boolean,
/**
* Note: may have bugs (missing content) in some circumstances - use at your own risk.
*
* This may improve scroll performance for large lists.
*/
removeClippedSubviews?: boolean,
/**
* Rendered at the top of each section. These stick to the top of the `ScrollView` by default on
* iOS. See `stickySectionHeadersEnabled`.
*/
renderSectionHeader?: ?(info: {section: SectionT}) => ?React.Element<any>,
/**
* Rendered at the bottom of each section.
*/
renderSectionFooter?: ?(info: {section: SectionT}) => ?React.Element<any>,
/**
* Makes section headers stick to the top of the screen until the next one pushes it off. Only
* enabled by default on iOS because that is the platform standard there.
*/
stickySectionHeadersEnabled?: boolean,
legacyImplementation?: ?boolean,
};
type Props<SectionT> = RequiredProps<SectionT> &
OptionalProps<SectionT> &
VirtualizedSectionListProps<SectionT>;
const defaultProps = {
...VirtualizedSectionList.defaultProps,
stickySectionHeadersEnabled: Platform.OS === 'ios',
};
type DefaultProps = typeof defaultProps;
/**
* A performant interface for rendering sectioned lists, supporting the most handy features:
*
* - Fully cross-platform.
* - Configurable viewability callbacks.
* - List header support.
* - List footer support.
* - Item separator support.
* - Section header support.
* - Section separator support.
* - Heterogeneous data and item rendering support.
* - Pull to Refresh.
* - Scroll loading.
*
* If you don't need section support and want a simpler interface, use
* [`<FlatList>`](/react-native/docs/flatlist.html).
*
* Simple Examples:
*
* <SectionList
* renderItem={({item}) => <ListItem title={item.title} />}
* renderSectionHeader={({section}) => <H1 title={section.title} />}
* sections={[ // homogenous rendering between sections
* {data: [...], title: ...},
* {data: [...], title: ...},
* {data: [...], title: ...},
* ]}
* />
*
* <SectionList
* sections={[ // heterogeneous rendering between sections
* {data: [...], title: ..., renderItem: ...},
* {data: [...], title: ..., renderItem: ...},
* {data: [...], title: ..., renderItem: ...},
* ]}
* />
*
* This is a convenience wrapper around [`<VirtualizedList>`](docs/virtualizedlist.html),
* and thus inherits its props (as well as those of `ScrollView`) that aren't explicitly listed
* here, along with the following caveats:
*
* - Internal state is not preserved when content scrolls out of the render window. Make sure all
* your data is captured in the item data or external stores like Flux, Redux, or Relay.
* - This is a `PureComponent` which means that it will not re-render if `props` remain shallow-
* equal. Make sure that everything your `renderItem` function depends on is passed as a prop
* (e.g. `extraData`) that is not `===` after updates, otherwise your UI may not update on
* changes. This includes the `data` prop and parent component state.
* - In order to constrain memory and enable smooth scrolling, content is rendered asynchronously
* offscreen. This means it's possible to scroll faster than the fill rate and momentarily see
* blank content. This is a tradeoff that can be adjusted to suit the needs of each application,
* and we are working on improving it behind the scenes.
* - By default, the list looks for a `key` prop on each item and uses that for the React key.
* Alternatively, you can provide a custom `keyExtractor` prop.
*
*/
class SectionList<SectionT: SectionBase<any>> extends React.PureComponent<
DefaultProps,
Props<SectionT>,
void,
> {
props: Props<SectionT>;
static defaultProps: DefaultProps = defaultProps;
/**
* Scrolls to the item at the specified `sectionIndex` and `itemIndex` (within the section)
* positioned in the viewable area such that `viewPosition` 0 places it at the top (and may be
* covered by a sticky header), 1 at the bottom, and 0.5 centered in the middle. `viewOffset` is a
* fixed number of pixels to offset the final target position, e.g. to compensate for sticky
* headers.
*
* Note: cannot scroll to locations outside the render window without specifying the
* `getItemLayout` prop.
*/
scrollToLocation(params: {
animated?: ?boolean,
itemIndex: number,
sectionIndex: number,
viewOffset?: number,
viewPosition?: number,
}) {
this._wrapperListRef.scrollToLocation(params);
}
/**
* Tells the list an interaction has occured, which should trigger viewability calculations, e.g.
* if `waitForInteractions` is true and the user has not scrolled. This is typically called by
* taps on items or by navigation actions.
*/
recordInteraction() {
const listRef = this._wrapperListRef && this._wrapperListRef.getListRef();
listRef && listRef.recordInteraction();
}
/**
* Displays the scroll indicators momentarily.
*
* @platform ios
*/
flashScrollIndicators() {
const listRef = this._wrapperListRef && this._wrapperListRef.getListRef();
listRef && listRef.flashScrollIndicators();
}
/**
* Provides a handle to the underlying scroll responder.
*/
getScrollResponder() {
const listRef = this._wrapperListRef && this._wrapperListRef.getListRef();
if (listRef) {
return listRef.getScrollResponder();
}
}
getScrollableNode() {
const listRef = this._wrapperListRef && this._wrapperListRef.getListRef();
if (listRef) {
return listRef.getScrollableNode();
}
}
render() {
const List = this.props.legacyImplementation
? MetroListView
: VirtualizedSectionList;
return <List {...this.props} ref={this._captureRef} />;
}
_wrapperListRef: MetroListView | VirtualizedSectionList<any>;
_captureRef = ref => {
this._wrapperListRef = ref;
};
}
module.exports = SectionList;