SectionList

SectionList

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>.

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>, and thus inherits it's 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 ands 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.

Props

ItemSeparatorComponent?: ?ReactClass<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.

ListEmptyComponent?: ?ReactClass<any> | React.Element<any>

Rendered when the list is empty. Can be a React Component Class, a render function, or a rendered element.

ListFooterComponent?: ?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.

ListHeaderComponent?: ?ReactClass<any> | React.Element<any>

Rendered at the very beginning of the list. Can be a React Component Class, a render function, or a rendered element.

SectionSeparatorComponent?: ?ReactClass<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.

extraData?: 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.

initialNumToRender: number

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.

keyExtractor: (item: Item, index: number) => string

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.

legacyImplementation?: ?boolean

onEndReached?: ?(info: {distanceFromEnd: number}) => void

Called once when the scroll position gets within onEndReachedThreshold of the rendered content.

onEndReachedThreshold?: ?number

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.

onRefresh?: ?() => void

If provided, a standard RefreshControl will be added for "Pull to Refresh" functionality. Make sure to also set the refreshing prop correctly.

onViewableItemsChanged?: ?(info: { viewableItems: Array<ViewToken>, changed: Array<ViewToken>, }) => void

Called when the viewability of rows changes, as defined by the viewabilityConfig prop.

refreshing?: ?boolean

Set this true while waiting for new data from a refresh.

removeClippedSubviews?: boolean

Note: may have bugs (missing content) in some circumstances - use at your own risk.

This may improve scroll performance for large lists.

renderItem: (info: { item: Item, index: number, section: SectionT, separators: { highlight: () => void, unhighlight: () => void, updateProps: (select: 'leading' | 'trailing', newProps: Object) => void, }, }) => ?React.Element<any>

Default renderer for every item in every section. Can be over-ridden on a per-section basis.

renderSectionFooter?: ?(info: {section: SectionT}) => ?React.Element<any>

Rendered at the bottom of each section.

renderSectionHeader?: ?(info: {section: SectionT}) => ?React.Element<any>

Rendered at the top of each section. These stick to the top of the ScrollView by default on iOS. See stickySectionHeadersEnabled.

sections: $ReadOnlyArray<SectionT>

The actual data to render, akin to the data prop in <FlatList>.

General shape:

sections: $ReadOnlyArray<{
  data: $ReadOnlyArray<SectionItem>,
  renderItem?: ({item: SectionItem, ...}) => ?React.Element<*>,
  ItemSeparatorComponent?: ?ReactClass<{highlighted: boolean, ...}>,
}>

stickySectionHeadersEnabled?: boolean

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.

Methods

scrollToLocation(params: object)

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.

recordInteraction()

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.