react-native/Libraries/Experimental/VirtualizedSectionList.js

318 lines
11 KiB
JavaScript

/**
* Copyright (c) 2013-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.
*
* Facebook, Inc. ("Facebook") owns all right, title and interest, including
* all intellectual property and other proprietary rights, in and to the React
* Native CustomComponents software (the "Software"). Subject to your
* compliance with these terms, you are hereby granted a non-exclusive,
* worldwide, royalty-free copyright license to (1) use and copy the Software;
* and (2) reproduce and distribute the Software as part of your own software
* ("Your Software"). Facebook reserves all rights not expressly granted to
* you in this license agreement.
*
* THE SOFTWARE AND DOCUMENTATION, IF ANY, ARE PROVIDED "AS IS" AND ANY EXPRESS
* OR IMPLIED WARRANTIES (INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE) ARE DISCLAIMED.
* IN NO EVENT SHALL FACEBOOK OR ITS AFFILIATES, OFFICERS, DIRECTORS OR
* EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THE SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @providesModule VirtualizedSectionList
* @flow
*/
'use strict';
const React = require('React');
const View = require('View');
const VirtualizedList = require('VirtualizedList');
const invariant = require('invariant');
const warning = require('warning');
import type {Viewable} from 'ViewabilityHelper';
import type {Props as VirtualizedListProps} from 'VirtualizedList';
type Item = any;
type SectionItem = any;
type SectionBase = {
// Must be provided directly on each section.
data: Array<SectionItem>,
key: string,
// Optional props will override list-wide props just for this section.
ItemComponent?: ?ReactClass<{item: SectionItem, index: number}>,
SeparatorComponent?: ?ReactClass<*>,
keyExtractor?: (item: SectionItem) => string,
// TODO: support more optional/override props
// FooterComponent?: ?ReactClass<*>,
// HeaderComponent?: ?ReactClass<*>,
// onViewableItemsChanged?: ({viewableItems: Array<Viewable>, changed: Array<Viewable>}) => void,
// TODO: support recursive sections
// SectionHeaderComponent?: ?ReactClass<{section: SectionBase}>,
// sections?: ?Array<Section>;
};
type RequiredProps<SectionT: SectionBase> = {
sections: Array<SectionT>,
};
type OptionalProps<SectionT: SectionBase> = {
/**
* Rendered after the last item in the last section.
*/
FooterComponent?: ?ReactClass<*>,
/**
* Default renderer for every item in every section.
*/
ItemComponent: ReactClass<{item: Item, index: number}>,
/**
* Rendered at the top of each section. In the future, a sticky option will be added.
*/
SectionHeaderComponent?: ?ReactClass<{section: SectionT}>,
/**
* Rendered at the bottom of every Section, except the very last one, in place of the normal
* SeparatorComponent.
*/
SectionSeparatorComponent?: ?ReactClass<*>,
/**
* Rendered at the bottom of every Item except the very last one in the last section.
*/
SeparatorComponent?: ?ReactClass<*>,
/**
* Warning: Virtualization can drastically improve memory consumption for long lists, but trashes
* the state of items when they scroll out of the render window, so make sure all relavent data is
* stored outside of the recursive `ItemComponent` instance tree.
*/
enableVirtualization?: ?boolean,
keyExtractor: (item: Item, index: number) => string,
onEndReached?: ?({distanceFromEnd: number}) => void,
/**
* If provided, a standard RefreshControl will be added for "Pull to Refresh" functionality. Make
* sure to also set the `refreshing` prop correctly.
*/
onRefresh?: ?Function,
/**
* Called when the viewability of rows changes, as defined by the
* `viewablePercentThreshold` prop.
*/
onViewableItemsChanged?: ?({viewableItems: Array<Viewable>, changed: Array<Viewable>}) => void,
/**
* Set this true while waiting for new data from a refresh.
*/
refreshing?: ?boolean,
/**
* This is an optional optimization to minimize re-rendering items.
*/
shouldItemUpdate: (
prevProps: {item: Item, index: number},
nextProps: {item: Item, index: number}
) => boolean,
};
export type Props<SectionT> =
RequiredProps<SectionT> &
OptionalProps<SectionT> &
VirtualizedListProps;
type DefaultProps = (typeof VirtualizedList.defaultProps) & {data: Array<Item>};
type State = {childProps: VirtualizedListProps};
/**
* Right now this just flattens everything into one list and uses VirtualizedList under the
* hood. The only operation that might not scale well is concatting the data arrays of all the
* sections when new props are received, which should be plenty fast for up to ~10,000 items.
*/
class VirtualizedSectionList<SectionT: SectionBase>
extends React.PureComponent<DefaultProps, Props<SectionT>, State>
{
props: Props<SectionT>;
state: State;
static defaultProps: DefaultProps = {
...VirtualizedList.defaultProps,
data: [],
};
_keyExtractor = (item: Item, index: number) => {
const info = this._subExtractor(index);
return (info && info.key) || String(index);
};
_subExtractor(
index: number,
): ?{
section: SectionT,
key: string, // Key of the section or combined key for section + item
index: ?number, // Relative index within the section
} {
let itemIndex = index;
const defaultKeyExtractor = this.props.keyExtractor;
for (let ii = 0; ii < this.props.sections.length; ii++) {
const section = this.props.sections[ii];
const key = section.key;
warning(
key != null,
'VirtualizedSectionList: A `section` you supplied is missing the `key` property.'
);
itemIndex -= 1; // The section itself is an item
if (itemIndex >= section.data.length) {
itemIndex -= section.data.length;
} else if (itemIndex === -1) {
return {section, key, index: null};
} else {
const keyExtractor = section.keyExtractor || defaultKeyExtractor;
return {
section,
key: key + ':' + keyExtractor(section.data[itemIndex], itemIndex),
index: itemIndex,
};
}
}
}
_convertViewable = (viewable: Viewable): ?Viewable => {
invariant(viewable.index != null, 'Received a broken Viewable');
const info = this._subExtractor(viewable.index);
if (!info) {
return null;
}
const keyExtractor = info.section.keyExtractor || this.props.keyExtractor;
return {
...viewable,
index: info.index,
key: keyExtractor(viewable.item, info.index),
section: info.section,
};
};
_onViewableItemsChanged = (
{viewableItems, changed}: {viewableItems: Array<Viewable>, changed: Array<Viewable>}
) => {
if (this.props.onViewableItemsChanged) {
this.props.onViewableItemsChanged({
viewableItems: viewableItems.map(this._convertViewable, this).filter(Boolean),
changed: changed.map(this._convertViewable, this).filter(Boolean),
});
}
}
_isItemSticky = (item, index) => {
const info = this._subExtractor(index);
return info && info.index == null;
};
_renderItem = ({item, index}: {item: Item, index: number}) => {
const info = this._subExtractor(index);
if (!info) {
return null;
} else if (info.index == null) {
const {SectionHeaderComponent} = this.props;
return SectionHeaderComponent ? <SectionHeaderComponent section={info.section} /> : null;
} else {
const ItemComponent = info.section.ItemComponent || this.props.ItemComponent;
const SeparatorComponent = this._getSeparatorComponent(index, info);
return (
<View>
<ItemComponent item={item} index={info.index} />
{SeparatorComponent && <SeparatorComponent />}
</View>
);
}
};
_getSeparatorComponent(index: number, info?: ?Object): ?ReactClass<*> {
info = info || this._subExtractor(index);
if (!info) {
return null;
}
const SeparatorComponent = info.section.SeparatorComponent || this.props.SeparatorComponent;
const {SectionSeparatorComponent} = this.props;
const isLastItemInList = index === this.state.childProps.getItemCount() - 1;
const isLastItemInSection = info.index === info.section.data.length - 1;
if (SectionSeparatorComponent && isLastItemInSection && !isLastItemInList) {
return SectionSeparatorComponent;
}
if (SeparatorComponent && !isLastItemInSection && !isLastItemInList) {
return SeparatorComponent;
}
return null;
}
_shouldItemUpdate = (prev, next) => {
const {shouldItemUpdate} = this.props;
if (!shouldItemUpdate || shouldItemUpdate(prev, next)) {
return true;
}
return this._getSeparatorComponent(prev.index) !== this._getSeparatorComponent(next.index);
}
_computeState(props: Props<SectionT>): State {
const itemCount = props.sections.reduce((v, section) => v + section.data.length + 1, 0);
return {
childProps: {
...props,
ItemComponent: this._renderItem,
SeparatorComponent: undefined, // Rendered with ItemComponent
data: props.sections,
getItemCount: () => itemCount,
getItem,
isItemSticky: this._isItemSticky,
keyExtractor: this._keyExtractor,
onViewableItemsChanged:
props.onViewableItemsChanged ? this._onViewableItemsChanged : undefined,
shouldItemUpdate: this._shouldItemUpdate,
},
};
}
constructor(props: Props<SectionT>, context: Object) {
super(props, context);
warning(
!props.stickySectionHeadersEnabled,
'VirtualizedSectionList: Sticky headers only supported with legacyImplementation for now.'
);
this.state = this._computeState(props);
}
componentWillReceiveProps(nextProps: Props<SectionT>) {
this.setState(this._computeState(nextProps));
}
render() {
return <VirtualizedList {...this.state.childProps} />;
}
}
function getItem(sections: ?Array<Item>, index: number): ?Item {
if (!sections) {
return null;
}
let itemIdx = index - 1;
for (let ii = 0; ii < sections.length; ii++) {
if (itemIdx === -1) {
return sections[ii]; // The section itself is the item
} else if (itemIdx < sections[ii].data.length) {
return sections[ii].data[itemIdx];
} else {
itemIdx -= (sections[ii].data.length + 1);
}
}
return null;
}
module.exports = VirtualizedSectionList;