ScrollerCompat

class ScrollerCompat

kotlin.Any
↳	androidx.core.widget.ScrollerCompat

Provides access to new Scroller APIs when available.

This class provides a platform version-independent mechanism for obeying the current device's preferred scroll physics and fling behavior. It offers a subset of the APIs from Scroller or OverScroller.

Summary

Public methods
Int	`getCurrY()` Returns the current Y offset in the scroll.
Unit	`startScroll(startX: Int, startY: Int, dx: Int, dy: Int)` Start scrolling by providing a starting point and the distance to travel.
Unit	`startScroll(startX: Int, startY: Int, dx: Int, dy: Int, duration: Int)` Start scrolling by providing a starting point and the distance to travel.
Boolean	`computeScrollOffset()` Call this when you want to know the new location.
Unit	`abortAnimation()` Stops the animation.
Boolean	`isOverScrolled()` Returns whether the current Scroller is currently returning to a valid position.
Float	`getCurrVelocity()` Returns the current velocity on platform versions that support it.
Unit	`notifyVerticalEdgeReached(startY: Int, finalY: Int, overY: Int)` Notify the scroller that we've reached a vertical boundary.
Unit	`fling(startX: Int, startY: Int, velocityX: Int, velocityY: Int, minX: Int, maxX: Int, minY: Int, maxY: Int)` Start scrolling based on a fling gesture.
Unit	`fling(startX: Int, startY: Int, velocityX: Int, velocityY: Int, minX: Int, maxX: Int, minY: Int, maxY: Int, overX: Int, overY: Int)` Start scrolling based on a fling gesture.
Unit	`notifyHorizontalEdgeReached(startX: Int, finalX: Int, overX: Int)` Notify the scroller that we've reached a horizontal boundary.
Int	`getFinalY()`
Boolean	`isFinished()` Returns whether the scroller has finished scrolling.
Int	`getFinalX()`
Int	`getCurrX()` Returns the current X offset in the scroll.
Boolean	`springBack(startX: Int, startY: Int, minX: Int, maxX: Int, minY: Int, maxY: Int)` Call this when you want to 'spring back' into a valid coordinate range.
static ScrollerCompat!	`create(context: Context!)`
static ScrollerCompat!	`create(context: Context!, interpolator: Interpolator!)`

Public methods

getCurrY

fun getCurrY(): Int

Returns the current Y offset in the scroll.

Return
Int: The new Y offset as an absolute distance from the origin.

startScroll

fun startScroll(startX: Int, startY: Int, dx: Int, dy: Int): Unit

Start scrolling by providing a starting point and the distance to travel. The scroll will use the default value of 250 milliseconds for the duration.

Parameters
`startX`	Int: Starting horizontal scroll offset in pixels. Positive numbers will scroll the content to the left.
`startY`	Int: Starting vertical scroll offset in pixels. Positive numbers will scroll the content up.
`dx`	Int: Horizontal distance to travel. Positive numbers will scroll the content to the left.
`dy`	Int: Vertical distance to travel. Positive numbers will scroll the content up.

startScroll

fun startScroll(startX: Int, startY: Int, dx: Int, dy: Int, duration: Int): Unit

Start scrolling by providing a starting point and the distance to travel.

Parameters
`startX`	Int: Starting horizontal scroll offset in pixels. Positive numbers will scroll the content to the left.
`startY`	Int: Starting vertical scroll offset in pixels. Positive numbers will scroll the content up.
`dx`	Int: Horizontal distance to travel. Positive numbers will scroll the content to the left.
`dy`	Int: Vertical distance to travel. Positive numbers will scroll the content up.
`duration`	Int: Duration of the scroll in milliseconds.

computeScrollOffset

fun computeScrollOffset(): Boolean

Call this when you want to know the new location. If it returns true, the animation is not yet finished. loc will be altered to provide the new location.

abortAnimation

fun abortAnimation(): Unit

Stops the animation. Aborting the animation causes the scroller to move to the final x and y position.

isOverScrolled

fun isOverScrolled(): Boolean

Returns whether the current Scroller is currently returning to a valid position. Valid bounds were provided by the fling(int, int, int, int, int, int, int, int, int, int) method. One should check this value before calling startScroll(int, int, int, int) as the interpolation currently in progress to restore a valid position will then be stopped. The caller has to take into account the fact that the started scroll will start from an overscrolled position.

Return
Boolean: true when the current position is overscrolled and in the process of interpolating back to a valid value.

getCurrVelocity

fun getCurrVelocity(): Float

Returns the current velocity on platform versions that support it.

This method should only be used as input for nonessential visual effects such as EdgeEffectCompat.

Return
Float: The original velocity less the deceleration. Result may be negative.

notifyVerticalEdgeReached

fun notifyVerticalEdgeReached(startY: Int, finalY: Int, overY: Int): Unit

Notify the scroller that we've reached a vertical boundary. Normally the information to handle this will already be known when the animation is started, such as in a call to one of the fling functions. However there are cases where this cannot be known in advance. This function will animate a parabolic motion from startY to finalY.

Parameters
`startY`	Int: Starting/current Y position
`finalY`	Int: Desired final Y position
`overY`	Int: Magnitude of overscroll allowed. This should be the maximum desired distance from finalY. Absolute value - must be positive.

fling

fun fling(startX: Int, startY: Int, velocityX: Int, velocityY: Int, minX: Int, maxX: Int, minY: Int, maxY: Int): Unit

Start scrolling based on a fling gesture. The distance travelled will depend on the initial velocity of the fling.

Parameters
`startX`	Int: Starting point of the scroll (X)
`startY`	Int: Starting point of the scroll (Y)
`velocityX`	Int: Initial velocity of the fling (X) measured in pixels per second.
`velocityY`	Int: Initial velocity of the fling (Y) measured in pixels per second
`minX`	Int: Minimum X value. The scroller will not scroll past this point.
`maxX`	Int: Maximum X value. The scroller will not scroll past this point.
`minY`	Int: Minimum Y value. The scroller will not scroll past this point.
`maxY`	Int: Maximum Y value. The scroller will not scroll past this point.

fling

fun fling(startX: Int, startY: Int, velocityX: Int, velocityY: Int, minX: Int, maxX: Int, minY: Int, maxY: Int, overX: Int, overY: Int): Unit

Start scrolling based on a fling gesture. The distance travelled will depend on the initial velocity of the fling.

Parameters
`startX`	Int: Starting point of the scroll (X)
`startY`	Int: Starting point of the scroll (Y)
`velocityX`	Int: Initial velocity of the fling (X) measured in pixels per second.
`velocityY`	Int: Initial velocity of the fling (Y) measured in pixels per second
`minX`	Int: Minimum X value. The scroller will not scroll past this point.
`maxX`	Int: Maximum X value. The scroller will not scroll past this point.
`minY`	Int: Minimum Y value. The scroller will not scroll past this point.
`maxY`	Int: Maximum Y value. The scroller will not scroll past this point.
`overX`	Int: Overfling range. If > 0, horizontal overfling in either direction will be possible.
`overY`	Int: Overfling range. If > 0, vertical overfling in either direction will be possible.

notifyHorizontalEdgeReached

fun notifyHorizontalEdgeReached(startX: Int, finalX: Int, overX: Int): Unit

Notify the scroller that we've reached a horizontal boundary. Normally the information to handle this will already be known when the animation is started, such as in a call to one of the fling functions. However there are cases where this cannot be known in advance. This function will transition the current motion and animate from startX to finalX as appropriate.

Parameters
`startX`	Int: Starting/current X position
`finalX`	Int: Desired final X position
`overX`	Int: Magnitude of overscroll allowed. This should be the maximum desired distance from finalX. Absolute value - must be positive.

getFinalY

fun getFinalY(): Int

Return
Int: The final Y position for the scroll in progress, if known.

isFinished

fun isFinished(): Boolean

Returns whether the scroller has finished scrolling.

Return
Boolean: True if the scroller has finished scrolling, false otherwise.

getFinalX

fun getFinalX(): Int

Return
Int: The final X position for the scroll in progress, if known.

getCurrX

fun getCurrX(): Int

Returns the current X offset in the scroll.

Return
Int: The new X offset as an absolute distance from the origin.

springBack

fun springBack(startX: Int, startY: Int, minX: Int, maxX: Int, minY: Int, maxY: Int): Boolean

Call this when you want to 'spring back' into a valid coordinate range.

Parameters
`startX`	Int: Starting X coordinate
`startY`	Int: Starting Y coordinate
`minX`	Int: Minimum valid X value
`maxX`	Int: Maximum valid X value
`minY`	Int: Minimum valid Y value
`maxY`	Int: Maximum valid Y value

Return
Boolean: true if a springback was initiated, false if startX and startY were already within the valid range.

create

static fun create(context: Context!): ScrollerCompat!

create

static fun create(context: Context!, interpolator: Interpolator!): ScrollerCompat!