TvLazyListState
class TvLazyListState : ScrollableState
A state object that can be hoisted to control and observe scrolling.
In most cases, this will be created via rememberTvLazyListState.
Summary
Public companion properties |
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Saver<TvLazyListState, *> |
The default |
Public constructors |
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TvLazyListState( |
Public functions |
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suspend Unit |
animateScrollToItem(index: Int, scrollOffset: Int)Animate (smooth scroll) to the given item. |
open Float |
dispatchRawDelta(delta: Float) |
open suspend Unit |
scroll(scrollPriority: MutatePriority, block: suspend ScrollScope.() -> Unit)Call this function to take control of scrolling and gain the ability to send scroll events via |
suspend Unit |
scrollToItem(index: Int, scrollOffset: Int)Instantly brings the item at |
Public properties |
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open Boolean |
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open Boolean |
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Int |
The index of the first item that is visible. |
Int |
The scroll offset of the first visible item. |
InteractionSource |
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open Boolean |
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TvLazyListLayoutInfo |
The object of |
Inherited properties |
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Public companion properties
Saver
val Saver: Saver<TvLazyListState, *>
The default Saver implementation for TvLazyListState.
Public constructors
TvLazyListState
TvLazyListState(
firstVisibleItemIndex: Int = 0,
firstVisibleItemScrollOffset: Int = 0
)
| Parameters | |
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firstVisibleItemIndex: Int = 0 |
the initial value for |
firstVisibleItemScrollOffset: Int = 0 |
the initial value for |
Public functions
animateScrollToItem
suspend fun animateScrollToItem(index: Int, scrollOffset: Int = 0): Unit
Animate (smooth scroll) to the given item.
| Parameters | |
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index: Int |
the index to which to scroll. Must be non-negative. |
scrollOffset: Int = 0 |
the offset that the item should end up after the scroll. Note that positive offset refers to forward scroll, so in a top-to-bottom list, positive offset will scroll the item further upward (taking it partly offscreen). |
scroll
open suspend fun scroll(scrollPriority: MutatePriority, block: suspend ScrollScope.() -> Unit): Unit
Call this function to take control of scrolling and gain the ability to send scroll events via ScrollScope.scrollBy. All actions that change the logical scroll position must be performed within a scroll block (even if they don't call any other methods on this object) in order to guarantee that mutual exclusion is enforced.
If scroll is called from elsewhere, this will be canceled.
scrollToItem
suspend fun scrollToItem(index: Int, scrollOffset: Int = 0): Unit
Instantly brings the item at index to the top of the viewport, offset by scrollOffset pixels.
| Parameters | |
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index: Int |
the index to which to scroll. Must be non-negative. |
scrollOffset: Int = 0 |
the offset that the item should end up after the scroll. Note that positive offset refers to forward scroll, so in a top-to-bottom list, positive offset will scroll the item further upward (taking it partly offscreen). |
Public properties
firstVisibleItemIndex
val firstVisibleItemIndex: Int
The index of the first item that is visible.
Note that this property is observable and if you use it in the composable function it will be recomposed on every change causing potential performance issues.
If you want to run some side effects like sending an analytics event or updating a state based on this value consider using "snapshotFlow".
If you need to use it in the composition then consider wrapping the calculation into a derived state in order to only have recompositions when the derived value changes.
firstVisibleItemScrollOffset
val firstVisibleItemScrollOffset: Int
The scroll offset of the first visible item. Scrolling forward is positive - i.e., the amount that the item is offset backwards.
Note that this property is observable and if you use it in the composable function it will be recomposed on every scroll causing potential performance issues.
| See also | |
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firstVisibleItemIndex |
for samples with the recommended usage patterns. |
interactionSource
val interactionSource: InteractionSource
InteractionSource that will be used to dispatch drag events when this list is being dragged. If you want to know whether the fling (or animated scroll) is in progress, use isScrollInProgress.
layoutInfo
val layoutInfo: TvLazyListLayoutInfo
The object of TvLazyListLayoutInfo calculated during the last layout pass. For example, you can use it to calculate what items are currently visible.
Note that this property is observable and is updated after every scroll or remeasure. If you use it in the composable function it will be recomposed on every change causing potential performance issues including infinity recomposition loop. Therefore, avoid using it in the composition.
If you want to run some side effects like sending an analytics event or updating a state based on this value consider using "snapshotFlow"