19 KiB
id | title | layout | category | permalink | next | previous |
---|---|---|---|---|---|---|
scrollview | ScrollView | docs | components | docs/scrollview.html | sectionlist | refreshcontrol |
Component that wraps platform ScrollView while providing integration with touch locking "responder" system.
Keep in mind that ScrollViews must have a bounded height in order to work,
since they contain unbounded-height children into a bounded container (via
a scroll interaction). In order to bound the height of a ScrollView, either
set the height of the view directly (discouraged) or make sure all parent
views have bounded height. Forgetting to transfer {flex: 1}
down the
view stack can lead to errors here, which the element inspector makes
easy to debug.
Doesn't yet support other contained responders from blocking this scroll view from becoming the responder.
<ScrollView>
vs <FlatList>
- which one to use?
ScrollView
simply renders all its react child components at once. That
makes it very easy to understand and use.
On the other hand, this has a performance downside. Imagine you have a very long list of items you want to display, maybe several screens worth of content. Creating JS components and native views for everything all at once, much of which may not even be shown, will contribute to slow rendering and increased memory usage.
This is where FlatList
comes into play. FlatList
renders items lazily,
just when they are about to appear, and removes items that scroll way off
screen to save memory and processing time.
FlatList
is also handy if you want to render separators between your items,
multiple columns, infinite scroll loading, or any number of other features it
supports out of the box.
Props
- View props...
alwaysBounceVertical
contentContainerStyle
keyboardDismissMode
keyboardShouldPersistTaps
onContentSizeChange
onMomentumScrollBegin
onMomentumScrollEnd
onScroll
pagingEnabled
refreshControl
removeClippedSubviews
scrollEnabled
showsHorizontalScrollIndicator
showsVerticalScrollIndicator
stickyHeaderIndices
endFillColor
overScrollMode
scrollPerfTag
alwaysBounceHorizontal
horizontal
automaticallyAdjustContentInsets
bounces
bouncesZoom
canCancelContentTouches
centerContent
contentInset
contentInsetAdjustmentBehavior
contentOffset
decelerationRate
directionalLockEnabled
indicatorStyle
maximumZoomScale
minimumZoomScale
pinchGestureEnabled
scrollEventThrottle
scrollIndicatorInsets
scrollsToTop
snapToAlignment
snapToInterval
zoomScale
DEPRECATED_sendUpdatedChildFrames
Methods
Reference
Props
alwaysBounceVertical
When true, the scroll view bounces vertically when it reaches the end
even if the content is smaller than the scroll view itself. The default
value is false when horizontal={true}
and true otherwise.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
contentContainerStyle
These styles will be applied to the scroll view content container which wraps all of the child views. Example:
return (
<ScrollView contentContainerStyle={styles.contentContainer}>
</ScrollView>
);
...
const styles = StyleSheet.create({
contentContainer: {
paddingVertical: 20
}
});
Type | Required |
---|---|
style | No |
keyboardDismissMode
Determines whether the keyboard gets dismissed in response to a drag.
Cross platform
'none'
(the default), drags do not dismiss the keyboard.'on-drag'
, the keyboard is dismissed when a drag begins.
iOS Only
'interactive'
, the keyboard is dismissed interactively with the drag and moves in synchrony with the touch; dragging upwards cancels the dismissal. On android this is not supported and it will have the same behavior as 'none'.
Type | Required |
---|---|
enum('none', 'on-drag', 'interactive') | No |
keyboardShouldPersistTaps
Determines when the keyboard should stay visible after a tap.
'never'
(the default), tapping outside of the focused text input when the keyboard is up dismisses the keyboard. When this happens, children won't receive the tap.'always'
, the keyboard will not dismiss automatically, and the scroll view will not catch taps, but children of the scroll view can catch taps.'handled'
, the keyboard will not dismiss automatically when the tap was handled by a children, (or captured by an ancestor).false
, deprecated, use 'never' insteadtrue
, deprecated, use 'always' instead
Type | Required |
---|---|
enum('always', 'never', 'handled', false, true) | No |
onContentSizeChange
Called when scrollable content view of the ScrollView changes.
Handler function is passed the content width and content height as parameters:
(contentWidth, contentHeight)
It's implemented using onLayout handler attached to the content container which this ScrollView renders.
Type | Required |
---|---|
function | No |
onMomentumScrollBegin
Called when the momentum scroll starts (scroll which occurs as the ScrollView glides to a stop).
Type | Required |
---|---|
function | No |
onMomentumScrollEnd
Called when the momentum scroll ends (scroll which occurs as the ScrollView glides to a stop).
Type | Required |
---|---|
function | No |
onScroll
Fires at most once per frame during scrolling. The frequency of the
events can be controlled using the scrollEventThrottle
prop.
Type | Required |
---|---|
function | No |
pagingEnabled
When true, the scroll view stops on multiples of the scroll view's size when scrolling. This can be used for horizontal pagination. The default value is false.
Note: Vertical pagination is not supported on Android.
Type | Required |
---|---|
bool | No |
refreshControl
A RefreshControl component, used to provide pull-to-refresh
functionality for the ScrollView. Only works for vertical ScrollViews
(horizontal
prop must be false
).
See RefreshControl.
Type | Required |
---|---|
element | No |
removeClippedSubviews
Experimental: When true, offscreen child views (whose overflow
value is
hidden
) are removed from their native backing superview when offscreen.
This can improve scrolling performance on long lists. The default value is
true.
Type | Required |
---|---|
bool | No |
scrollEnabled
When false, the view cannot be scrolled via touch interaction. The default value is true.
Note that the view can always be scrolled by calling scrollTo
.
Type | Required |
---|---|
bool | No |
showsHorizontalScrollIndicator
When true, shows a horizontal scroll indicator. The default value is true.
Type | Required |
---|---|
bool | No |
showsVerticalScrollIndicator
When true, shows a vertical scroll indicator. The default value is true.
Type | Required |
---|---|
bool | No |
stickyHeaderIndices
An array of child indices determining which children get docked to the
top of the screen when scrolling. For example, passing
stickyHeaderIndices={[0]}
will cause the first child to be fixed to the
top of the scroll view. This property is not supported in conjunction
with horizontal={true}
.
Type | Required |
---|---|
array of number | No |
endFillColor
Sometimes a scrollview takes up more space than its content fills. When this is the case, this prop will fill the rest of the scrollview with a color to avoid setting a background and creating unnecessary overdraw. This is an advanced optimization that is not needed in the general case.
Type | Required | Platform |
---|---|---|
color | No | Android |
overScrollMode
Used to override default value of overScroll mode.
Possible values:
'auto'
- Default value, allow a user to over-scroll this view only if the content is large enough to meaningfully scroll.'always'
- Always allow a user to over-scroll this view.'never'
- Never allow a user to over-scroll this view.
Type | Required | Platform |
---|---|---|
enum('auto', 'always', 'never') | No | Android |
scrollPerfTag
Tag used to log scroll performance on this scroll view. Will force momentum events to be turned on (see sendMomentumEvents). This doesn't do anything out of the box and you need to implement a custom native FpsListener for it to be useful.
Type | Required | Platform |
---|---|---|
string | No | Android |
alwaysBounceHorizontal
When true, the scroll view bounces horizontally when it reaches the end
even if the content is smaller than the scroll view itself. The default
value is true when horizontal={true}
and false otherwise.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
horizontal
When true, the scroll view's children are arranged horizontally in a row instead of vertically in a column. The default value is false.
Type | Required |
---|---|
bool | No |
automaticallyAdjustContentInsets
Controls whether iOS should automatically adjust the content inset for scroll views that are placed behind a navigation bar or tab bar/ toolbar. The default value is true.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
bounces
When true, the scroll view bounces when it reaches the end of the
content if the content is larger then the scroll view along the axis of
the scroll direction. When false, it disables all bouncing even if
the alwaysBounce*
props are true. The default value is true.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
bouncesZoom
When true, gestures can drive zoom past min/max and the zoom will animate to the min/max value at gesture end, otherwise the zoom will not exceed the limits.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
canCancelContentTouches
When false, once tracking starts, won't try to drag if the touch moves. The default value is true.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
centerContent
When true, the scroll view automatically centers the content when the content is smaller than the scroll view bounds; when the content is larger than the scroll view, this property has no effect. The default value is false.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
contentInset
The amount by which the scroll view content is inset from the edges
of the scroll view. Defaults to {top: 0, left: 0, bottom: 0, right: 0}
.
Type | Required | Platform |
---|---|---|
object: {top: number, left: number, bottom: number, right: number} | No | iOS |
contentInsetAdjustmentBehavior
This property specifies how the safe area insets are used to modify the content area of the scroll view. The default value of this property is "never". Available on iOS 11 and later.
Type | Required | Platform |
---|---|---|
enum('automatic', 'scrollableAxes', 'never', 'always') | No | iOS |
contentOffset
Used to manually set the starting scroll offset.
The default value is {x: 0, y: 0}
.
Type | Required | Platform |
---|---|---|
PointPropType | No | iOS |
decelerationRate
A floating-point number that determines how quickly the scroll view
decelerates after the user lifts their finger. You may also use string
shortcuts "normal"
and "fast"
which match the underlying iOS settings
for UIScrollViewDecelerationRateNormal
and
UIScrollViewDecelerationRateFast
respectively.
'normal'
: 0.998 (the default)'fast'
: 0.99
Type | Required | Platform |
---|---|---|
enum('fast', 'normal'), ,number | No | iOS |
directionalLockEnabled
When true, the ScrollView will try to lock to only vertical or horizontal scrolling while dragging. The default value is false.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
indicatorStyle
The style of the scroll indicators.
'default'
(the default), same asblack
.'black'
, scroll indicator is black. This style is good against a light background.'white'
, scroll indicator is white. This style is good against a dark background.
Type | Required | Platform |
---|---|---|
enum('default', 'black', 'white') | No | iOS |
maximumZoomScale
The maximum allowed zoom scale. The default value is 1.0.
Type | Required | Platform |
---|---|---|
number | No | iOS |
minimumZoomScale
The minimum allowed zoom scale. The default value is 1.0.
Type | Required | Platform |
---|---|---|
number | No | iOS |
pinchGestureEnabled
When true, ScrollView allows use of pinch gestures to zoom in and out. The default value is true.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
scrollEventThrottle
This controls how often the scroll event will be fired while scrolling (as a time interval in ms). A lower number yields better accuracy for code that is tracking the scroll position, but can lead to scroll performance problems due to the volume of information being send over the bridge. You will not notice a difference between values set between 1-16 as the JS run loop is synced to the screen refresh rate. If you do not need precise scroll position tracking, set this value higher to limit the information being sent across the bridge. The default value is zero, which results in the scroll event being sent only once each time the view is scrolled.
Type | Required | Platform |
---|---|---|
number | No | iOS |
scrollIndicatorInsets
The amount by which the scroll view indicators are inset from the edges
of the scroll view. This should normally be set to the same value as
the contentInset
. Defaults to {0, 0, 0, 0}
.
Type | Required | Platform |
---|---|---|
object: {top: number, left: number, bottom: number, right: number} | No | iOS |
scrollsToTop
When true, the scroll view scrolls to top when the status bar is tapped. The default value is true.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
snapToAlignment
When snapToInterval
is set, snapToAlignment
will define the relationship
of the snapping to the scroll view.
'start'
(the default) will align the snap at the left (horizontal) or top (vertical)'center'
will align the snap in the center'end'
will align the snap at the right (horizontal) or bottom (vertical)
Type | Required | Platform |
---|---|---|
enum('start', 'center', 'end') | No | iOS |
snapToInterval
When set, causes the scroll view to stop at multiples of the value of
snapToInterval
. This can be used for paginating through children
that have lengths smaller than the scroll view. Typically used in
combination with snapToAlignment
and decelerationRate="fast"
.
Overrides less configurable pagingEnabled
prop.
Type | Required | Platform |
---|---|---|
number | No | iOS |
zoomScale
The current scale of the scroll view content. The default value is 1.0.
Type | Required | Platform |
---|---|---|
number | No | iOS |
DEPRECATED_sendUpdatedChildFrames
Deprecated. When true, ScrollView will emit updateChildFrames data in scroll events,
otherwise will not compute or emit child frame data. This only exists
to support legacy issues, onLayout
should be used instead to retrieve
frame data.
The default value is false.
Type | Required | Platform |
---|---|---|
bool | No | iOS |
Methods
scrollTo()
scrollTo([y]: number, object, [x]: number, [animated]: boolean)
Scrolls to a given x, y offset, either immediately or with a smooth animation.
Example:
scrollTo({x: 0, y: 0, animated: true})
Note: The weird function signature is due to the fact that, for historical reasons, the function also accepts separate arguments as an alternative to the options object. This is deprecated due to ambiguity (y before x), and SHOULD NOT BE USED.
scrollToEnd()
scrollToEnd([options]: object)
If this is a vertical ScrollView scrolls to the bottom. If this is a horizontal ScrollView scrolls to the right.
Use scrollToEnd({animated: true})
for smooth animated scrolling,
scrollToEnd({animated: false})
for immediate scrolling.
If no options are passed, animated
defaults to true.
scrollWithoutAnimationTo()
scrollWithoutAnimationTo(y, x)
Deprecated, use scrollTo
instead.
flashScrollIndicators()
flashScrollIndicators()
Displays the scroll indicators momentarily.