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 quick 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 renders all its react child components at once, but 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, 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.

Example

import React from "react";

import { StyleSheet, Text, SafeAreaView, ScrollView } from "tbox/ui";

import Constants from "expo-constants";

const App = () => {

return (

<SafeAreaView style={styles.container}>

<ScrollView style={styles.scrollView}>

<Text style={styles.text}>

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do

eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad

minim veniam, quis nostrud exercitation ullamco laboris nisi ut

aliquip ex ea commodo consequat. Duis aute irure dolor in

reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla

pariatur. Excepteur sint occaecat cupidatat non proident, sunt in

culpa qui officia deserunt mollit anim id est laborum.

</Text>

</ScrollView>

</SafeAreaView>

);

};

const styles = StyleSheet.create({

container: {

flex: 1,

marginTop: Constants.statusBarHeight,

},

scrollView: {

backgroundColor: "pink",

marginHorizontal: 20,

},

text: {

fontSize: 42,

},

});

export default App;

---

Reference

Props

Inherits View Props.

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

---

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

---

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

---

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
StyleSheetPropType(View Style props)	No

---

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' (the default), 0.998 on iOS, 0.985 on Android.
• 'fast', 0.99 on iOS, 0.9 on Android.

Type	Required
enum('fast', 'normal'), ,number	No

---

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

---

disableIntervalMomentum

When true, the scroll view stops on the next index (in relation to scroll position at release) regardless of how fast the gesture is. This can be used for horizontal pagination when the page is less than the width of the ScrollView. The default value is false.

Type	Required
bool	No

---

disableScrollViewPanResponder

When true, the default JS pan responder on the ScrollView is disabled, and full control over touches inside the ScrollView is left to its child components. This is particularly useful if snapToInterval is enabled, since it does not follow typical touch patterns. Do not use this on regular ScrollView use cases without snapToInterval as it may cause unexpected touches to occur while scrolling. The default value is false.

Type	Required
bool	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

---

fadingEdgeLength

Fades out the edges of the the scroll content.

If the value is greater than 0, the fading edges will be set accordingly to the current scroll direction and position, indicating if there is more content to show.

Type	Required	Default	Platform
number	No	0	Android

---

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

---

indicatorStyle

The style of the scroll indicators.

• 'default' (the default), same as black.
• '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

---

invertStickyHeaders

If sticky headers should stick at the bottom instead of the top of the ScrollView. This is usually used with inverted ScrollViews.

Type	Required
bool	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 children of the scroll view (or captured by an ancestor).
• false, deprecated, use 'never' instead
• true, deprecated, use 'always' instead

Type	Required
enum('always', 'never', 'handled', false, true)	No

---

maintainVisibleContentPosition

When set, the scroll view will adjust the scroll position so that the first child that is currently visible and at or beyond minIndexForVisible will not change position. This is useful for lists that are loading content in both directions, e.g. a chat thread, where new messages coming in might otherwise cause the scroll position to jump. A value of 0 is common, but other values such as 1 can be used to skip loading spinners or other content that should not maintain position.

The optional autoscrollToTopThreshold can be used to make the content automatically scroll to the top after making the adjustment if the user was within the threshold of the top before the adjustment was made. This is also useful for chat-like applications where you want to see new messages scroll into place, but not if the user has scrolled up a ways and it would be disruptive to scroll a bunch.

Caveat 1: Reordering elements in the scrollview with this enabled will probably cause jumpiness and jank. It can be fixed, but there are currently no plans to do so. For now, don't re-order the content of any ScrollViews or Lists that use this feature.

Caveat 2: This uses contentOffset and frame.origin in native code to compute visibility. Occlusion, transforms, and other complexity won't be taken into account as to whether content is "visible" or not.

Type	Required	Platform
object: { minIndexForVisible: number, autoscrollToTopThreshold: number }	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

---

nestedScrollEnabled

Enables nested scrolling for Android API level 21+. Nested scrolling is supported by default on iOS.

Type	Required	Platform
bool	No	Android

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 starts gliding).

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. The event has the following shape (all values are numbers):

{

nativeEvent: {

contentInset: {bottom, left, right, top},

contentOffset: {x, y},

contentSize: {height, width},

layoutMeasurement: {height, width},

zoomScale

}

}

Type	Required
function	No

---

onScrollBeginDrag

Called when the user begins to drag the scroll view.

Type	Required
function	No

---

onScrollEndDrag

Called when the user stops dragging the scroll view and it either stops or begins to glide.

Type	Required
function	No

---

onScrollToTop

Fires when the scroll view scrolls to top after the status bar has been tapped.

Type	Required	Platform
function	No	iOS

---

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

---

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

---

persistentScrollbar

Causes the scrollbars not to turn transparent when they are not in use. The default value is false.

Type	Required	Platform
bool	No	Android

---

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

---

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.

Type	Required
bool	No

---

scrollBarThumbImage

Optionally an image can be used for the scroll bar thumb. This will override the color. While the image is loading or the image fails to load the color will be used instead. Use an alpha of 0 in the color to avoid seeing it while the image is loading.

• uri, a string representing the resource identifier for the image, which should be either a local file path or the name of a static image resource.
• number, opaque type returned by something like import IMAGE from './image.jpg'.

Type	Required	Platform
number	No	VR

---

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

---

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 sent 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

---

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

---

scrollToOverflowEnabled

When true, the scroll view can be programmatically scrolled beyond its content size. The default value is false.

Type	Required	Platform
bool	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

---

DEPRECATED_sendUpdatedChildFrames

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

---

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

---

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

---

snapToEnd

Use in conjunction with snapToOffsets. By default, the end of the list counts as a snap offset. Set snapToEnd to false to disable this behavior and allow the list to scroll freely between its end and the last snapToOffsets offset. The default value is true.

Type	Required
boolean	No

---

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
number	No

---

snapToOffsets

When set, causes the scroll view to stop at the defined offsets. This can be used for paginating through variously sized children that have lengths smaller than the scroll view. Typically used in combination with decelerationRate="fast". Overrides less configurable pagingEnabled and snapToInterval props.

Type	Required
array of number	No

---

snapToStart

Use in conjunction with snapToOffsets. By default, the beginning of the list counts as a snap offset. Set snapToStart to false to disable this behavior and allow the list to scroll freely between its start and the first snapToOffsets offset. The default value is true.

Type	Required
boolean	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

---

zoomScale

The current scale of the scroll view content. The default value is 1.0.

Type	Required	Platform
number	No	iOS

Methods

flashScrollIndicators()

flashScrollIndicators();

Displays the scroll indicators momentarily.

---

scrollTo()

scrollTo(

options?: {x?: number, y?: number, animated?: boolean} | number,

deprecatedX?: number,

deprecatedAnimated?: boolean,

);

Scrolls to a given x, y offset, either immediately, 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]: { animated: boolean, duration: number }));

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. For Android, you may specify a duration, e.g. scrollToEnd({duration: 500}) for a controlled duration scroll. If no options are passed, animated defaults to true.

---

scrollWithoutAnimationTo()

scrollWithoutAnimationTo(y, x);

Deprecated, use scrollTo instead.