# ListViewAutoScrollHelper
# ListViewAutoScrollHelper
Artifact:[androidx.core:core](https://developer.android.com/jetpack/androidx/releases/core)
[View Source](https://cs.android.com/search?q=file:androidx/core/widget/ListViewAutoScrollHelper.java+class:androidx.core.widget.ListViewAutoScrollHelper)
Added in[1.1.0](https://developer.android.com/jetpack/androidx/releases/core#1.1.0)
*** ** * ** ***
Kotlin\|[Java](https://developer.android.com/reference/androidx/core/widget/ListViewAutoScrollHelper "View this page in Java")
```
class ListViewAutoScrollHelper : AutoScrollHelper
```
|---|---|-----------------------------------------------------------------------------------------------------------------------------------------------|
| [kotlin.Any](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-any/index.html) |||
| ↳ | [androidx.core.widget.AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) ||
| | ↳ | [androidx.core.widget.ListViewAutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/ListViewAutoScrollHelper) |
*** ** * ** ***
An implementation of[AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper)that knows how to scroll through a[ListView](https://developer.android.com/reference/android/widget/ListView.html).
## Summary
| ### Public constructors |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [ListViewAutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/ListViewAutoScrollHelper#ListViewAutoScrollHelper(android.widget.ListView))`(target: `[ListView](https://developer.android.com/reference/android/widget/ListView.html)`)` |
| ### Public functions |
|-------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | [canTargetScrollHorizontally](https://developer.android.com/reference/kotlin/androidx/core/widget/ListViewAutoScrollHelper#canTargetScrollHorizontally(int))`(direction: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`)` Override this method to return whether the target view can be scrolled horizontally in a certain direction. |
| [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | [canTargetScrollVertically](https://developer.android.com/reference/kotlin/androidx/core/widget/ListViewAutoScrollHelper#canTargetScrollVertically(int))`(direction: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`)` Override this method to return whether the target view can be scrolled vertically in a certain direction. |
| [Unit](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-unit/index.html) | [scrollTargetBy](https://developer.android.com/reference/kotlin/androidx/core/widget/ListViewAutoScrollHelper#scrollTargetBy(int,int))`(deltaX: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`, deltaY: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`)` Override this method to scroll the target view by the specified number of pixels. |
| ### Inherited Constants |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| From[androidx.core.widget.AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) |-----------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `const `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html) | [EDGE_TYPE_INSIDE](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#EDGE_TYPE_INSIDE())` = 0` Edge type that specifies an activation area starting at the view bounds and extending inward. | | `const `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html) | [EDGE_TYPE_INSIDE_EXTEND](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#EDGE_TYPE_INSIDE_EXTEND())` = 1` Edge type that specifies an activation area starting at the view bounds and extending inward. | | `const `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html) | [EDGE_TYPE_OUTSIDE](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#EDGE_TYPE_OUTSIDE())` = 2` Edge type that specifies an activation area starting at the view bounds and extending outward. | | `const `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html) | [NO_MAX](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#NO_MAX())` = 3.4028235E38f` Constant passed to[setMaximumEdges](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMaximumEdges(float,float)),[setMaximumVelocity](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMaximumVelocity(float,float)), or[setMinimumVelocity](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMinimumVelocity(float,float)). | | `const `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html) | [NO_MIN](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#NO_MIN())` = 0.0f` Constant passed to[setMaximumEdges](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMaximumEdges(float,float)), or[setMaximumVelocity](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMaximumVelocity(float,float)), or[setMinimumVelocity](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMinimumVelocity(float,float)). | | `const `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html) | [RELATIVE_UNSPECIFIED](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#RELATIVE_UNSPECIFIED())` = 0.0f` Constant passed to[setRelativeEdges](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setRelativeEdges(float,float))or[setRelativeVelocity](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setRelativeVelocity(float,float)). | |
| ### Inherited functions |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| From[androidx.core.widget.AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) |-------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | [isEnabled](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#isEnabled())`()` | | [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | [isExclusive](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#isExclusive())`()` Indicates whether the scroll helper handles touch events exclusively during scrolling. | | [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | [onTouch](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#onTouch(android.view.View,android.view.MotionEvent))`(v: `[View](https://developer.android.com/reference/android/view/View.html)`!, event: `[MotionEvent](https://developer.android.com/reference/android/view/MotionEvent.html)`!)` Handles touch events by activating automatic scrolling, adjusting scroll velocity, or stopping. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setActivationDelay](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setActivationDelay(int))`(delayMillis: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`)` Sets the delay after entering an activation edge before activation of auto-scrolling. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setEdgeType](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setEdgeType(int))`(type: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`)` Sets the activation edge type, one of: | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper)`!` | [setEnabled](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setEnabled(boolean))`(enabled: `[Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html)`)` Sets whether the scroll helper is enabled and should respond to touch events. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper)`!` | [setExclusive](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setExclusive(boolean))`(exclusive: `[Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html)`)` Enables or disables exclusive handling of touch events during scrolling. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setMaximumEdges](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMaximumEdges(float,float))`(horizontalMax: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`, verticalMax: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`)` Sets the absolute maximum edge size. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setMaximumVelocity](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMaximumVelocity(float,float))`(horizontalMax: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`, verticalMax: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`)` Sets the absolute maximum scrolling velocity. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setMinimumVelocity](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setMinimumVelocity(float,float))`(horizontalMin: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`, verticalMin: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`)` Sets the absolute minimum scrolling velocity. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setRampDownDuration](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setRampDownDuration(int))`(durationMillis: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`)` Sets the amount of time after de-activation of auto-scrolling that is takes to slow to a stop. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setRampUpDuration](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setRampUpDuration(int))`(durationMillis: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html)`)` Sets the amount of time after activation of auto-scrolling that is takes to reach target velocity for the current touch position. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setRelativeEdges](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setRelativeEdges(float,float))`(horizontal: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`, vertical: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`)` Sets the activation edge size relative to the host view's dimensions. | | [AutoScrollHelper](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper) | [setRelativeVelocity](https://developer.android.com/reference/kotlin/androidx/core/widget/AutoScrollHelper#setRelativeVelocity(float,float))`(horizontal: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`, vertical: `[Float](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-float/index.html)`)` Sets the target scrolling velocity relative to the host view's dimensions. | |
| From[android.view.View.OnTouchListener](https://developer.android.com/reference/android/view/View.OnTouchListener.html) |------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `abstract `[Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | [onTouch](https://developer.android.com/reference/android/view/View.OnTouchListener.html#onTouch(android.view.View, android.view.MotionEvent))`(p: `[View](https://developer.android.com/reference/android/view/View.html)`!, p1: `[MotionEvent](https://developer.android.com/reference/android/view/MotionEvent.html)`!)` | |
## Public constructors
### ListViewAutoScrollHelper
Added in[1.1.0](https://developer.android.com/jetpack/androidx/releases/core#1.1.0)
```
ListViewAutoScrollHelper(target: ListView)
```
## Public functions
### canTargetScrollHorizontally
```
fun canTargetScrollHorizontally(direction: Int): Boolean
```
Override this method to return whether the target view can be scrolled horizontally in a certain direction.
| Parameters |
|------------------------------------------------------------------------------------------|----------------------------------------------------------------------|
| `direction: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html) | Negative to check scrolling left, positive to check scrolling right. |
| Returns |
|-------------------------------------------------------------------------------------|------------------------------------------------------------------------------------|
| [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | true if the target view is able to horizontally scroll in the specified direction. |
### canTargetScrollVertically
```
fun canTargetScrollVertically(direction: Int): Boolean
```
Override this method to return whether the target view can be scrolled vertically in a certain direction.
| Parameters |
|------------------------------------------------------------------------------------------|-------------------------------------------------------------------|
| `direction: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html) | Negative to check scrolling up, positive to check scrolling down. |
| Returns |
|-------------------------------------------------------------------------------------|----------------------------------------------------------------------------------|
| [Boolean](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html) | true if the target view is able to vertically scroll in the specified direction. |
### scrollTargetBy
```
fun scrollTargetBy(deltaX: Int, deltaY: Int): Unit
```
Override this method to scroll the target view by the specified number of pixels.
| Parameters |
|---------------------------------------------------------------------------------------|-------------------------------------------------|
| `deltaX: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html) | The number of pixels to scroll by horizontally. |
| `deltaY: `[Int](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-int/index.html) | The number of pixels to scroll by vertically. |