react-native/docs/virtualizedlist.md

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Base implementation for the more convenient <FlatList> and <SectionList> components, which are also better documented. In general, this should only really be used if you need more flexibility than FlatList provides, e.g. for use with immutable data instead of plain arrays.

Virtualization massively improves memory consumption and performance of large lists by maintaining a finite render window of active items and replacing all items outside of the render window with appropriately sized blank space. The window adapts to scrolling behavior, and items are rendered incrementally with low-pri (after any running interactions) if they are far from the visible area, or with hi-pri otherwise to minimize the potential of seeing blank space.

Some 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

Methods

Type Definitions


Reference

Props

last

Type Required
number Yes

first

Type Required
number Yes

horizontal

Type Required
No

initialNumToRender

Type Required
No

keyExtractor

Type Required
No

disableVirtualization

Type Required
No

maxToRenderPerBatch

Type Required
No

onEndReachedThreshold

Type Required
No

scrollEventThrottle

Type Required
No

updateCellsBatchingPeriod

Type Required
No

windowSize

Type Required
No

Methods

scrollToEnd()

scrollToEnd([params]: object)

scrollToIndex()

scrollToIndex(params: object)

scrollToItem()

scrollToItem(params: object)

scrollToOffset()

scrollToOffset(params: object)

Scroll to a specific content pixel offset in the list.

Param offset expects the offset to scroll to. In case of horizontal is true, the offset is the x-value, in any other case the offset is the y-value.

Param animated (true by default) defines whether the list should do an animation while scrolling.


recordInteraction()

recordInteraction()

flashScrollIndicators()

flashScrollIndicators()

Type Definitions

renderItemType

Type
FunctionTypeAnnotation

Props

Type
IntersectionTypeAnnotation