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>
.
Example
This is a convenience wrapper around <VirtualizedList>
, 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 ifprops
remain shallow-equal. Make sure that everything yourrenderItem
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 thedata
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 customkeyExtractor
prop.
Reference
Props
VirtualizedList Props
Inherits VirtualizedList Props.
RequiredrenderItem
Default renderer for every item in every section. Can be over-ridden on a per-section basis. Should return a React element.
Type |
---|
function |
The render function will be passed an object with the following keys:
- 'item' (object) - the item object as specified in this section's
data
key - 'index' (number) - Item's index within the section.
- 'section' (object) - The full section object as specified in
sections
. - 'separators' (object) - An object with the following keys:
- 'highlight' (function) -
() => void
- 'unhighlight' (function) -
() => void
- 'updateProps' (function) -
(select, newProps) => void
- 'select' (enum) - possible values are 'leading', 'trailing'
- 'newProps' (object)
- 'highlight' (function) -
Requiredsections
The actual data to render, akin to the data
prop in FlatList
.
Type |
---|
array of Sections |
extraData
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.
Type |
---|
any |
initialNumToRender
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.
Type | Default |
---|---|
number | 10 |
inverted
Reverses the direction of scroll. Uses scale transforms of -1.
Type | Default |
---|---|
boolean | false |
ItemSeparatorComponent
Rendered in between each item, but not at the top or bottom. By default, highlighted
, section
, and [leading/trailing][Item/Section]
props are provided. renderItem
provides separators.highlight
/unhighlight
which will update the highlighted
prop, but you can also add custom props with separators.updateProps
. Can be a React Component (e.g. SomeComponent
), or a React element (e.g. <SomeComponent />
).
Type |
---|
component, function, element |
keyExtractor
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.
Type |
---|
(item: object, index: number) => string |
ListEmptyComponent
Rendered when the list is empty. Can be a React Component (e.g. SomeComponent
), or a React element (e.g. <SomeComponent />
).
Type |
---|
component, element |
ListFooterComponent
Rendered at the very end of the list. Can be a React Component (e.g. SomeComponent
), or a React element (e.g. <SomeComponent />
).
Type |
---|
component, element |
ListHeaderComponent
Rendered at the very beginning of the list. Can be a React Component (e.g. SomeComponent
), or a React element (e.g. <SomeComponent />
).
Type |
---|
component, element |
onRefresh
If provided, a standard RefreshControl will be added for "Pull to Refresh" functionality. Make sure to also set the refreshing
prop correctly. To offset the RefreshControl from the top (e.g. by 100 pts), use progressViewOffset={100}
.
Type |
---|
function |
onViewableItemsChanged
Called when the viewability of rows changes, as defined by the viewabilityConfig
prop.
Type |
---|
(callback: {changed: ViewToken[], viewableItems: ViewToken[]}) => void |
refreshing
Set this true while waiting for new data from a refresh.
Type | Default |
---|---|
boolean | false |
removeClippedSubviews
Note: may have bugs (missing content) in some circumstances - use at your own risk.
This may improve scroll performance for large lists.
Type | Default |
---|---|
boolean | false |
renderSectionFooter
Rendered at the bottom of each section.
Type |
---|
(info: {section: Section}) => element | null |
renderSectionHeader
Rendered at the top of each section. These stick to the top of the ScrollView
by default on iOS. See stickySectionHeadersEnabled
.
Type |
---|
(info: {section: Section}) => element | null |
SectionSeparatorComponent
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/Section]
, and any custom props from separators.updateProps
.
Type |
---|
component, element |
stickySectionHeadersEnabled
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.
Type | Default |
---|---|
boolean | false Android true iOS |
Methods
flashScrollIndicators()
iOS
flashScrollIndicators();
Displays the scroll indicators momentarily.
recordInteraction()
recordInteraction();
Tells the list an interaction has occurred, 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.
scrollToLocation()
scrollToLocation(params: SectionListScrollParams);
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.
Note: Cannot scroll to locations outside the render window without specifying the
getItemLayout
oronScrollToIndexFailed
prop.
Parameters:
Name | Type |
---|---|
params Required | object |
Valid params
keys are:
- 'animated' (boolean) - Whether the list should do an animation while scrolling. Defaults to
true
. - 'itemIndex' (number) - Index within section for the item to scroll to. Required.
- 'sectionIndex' (number) - Index for section that contains the item to scroll to. Required.
- 'viewOffset' (number) - A fixed number of pixels to offset the final target position, e.g. to compensate for sticky headers.
- 'viewPosition' (number) - A value of
0
places the item specified by index at the top,1
at the bottom, and0.5
centered in the middle.
Type Definitions
Section
An object that identifies the data to be rendered for a given section.
Type |
---|
any |
Properties:
Name | Type | Description |
---|---|---|
data Required | array | The data for rendering items in this section. Array of objects, much like FlatList 's data prop. |
key | string | 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. |
renderItem | function | Optionally define an arbitrary item renderer for this section, overriding the default renderItem for the list. |
ItemSeparatorComponent | component, element | Optionally define an arbitrary item separator for this section, overriding the default ItemSeparatorComponent for the list. |
keyExtractor | function | Optionally define an arbitrary key extractor for this section, overriding the default keyExtractor . |