NestedScrollView

Kotlin |Java

open class NestedScrollView : FrameLayout, NestedScrollingParent3, NestedScrollingChild3, ScrollingView

kotlin.Any
↳	android.view.View
	↳	android.view.ViewGroup
		↳	android.widget.FrameLayout
			↳	androidx.core.widget.NestedScrollView

NestedScrollView is just like android.widget.ScrollView, but it supports acting as both a nested scrolling parent and child on both new and old versions of Android. Nested scrolling is enabled by default.

Summary

Nested classes
abstract	`OnScrollChangeListener` Interface definition for a callback to be invoked when the scroll X or Y positions of a view change.

Public constructors
`<init>(@NonNull context: Context)`
`<init>(@NonNull context: Context, @Nullable attrs: AttributeSet?)`
`<init>(@NonNull context: Context, @Nullable attrs: AttributeSet?, defStyleAttr: Int)`

Public methods
open Unit	`addView(child: View!)`
open Unit	`addView(child: View!, index: Int)`
open Unit	`addView(child: View!, params: LayoutParams!)`
open Unit	`addView(child: View!, index: Int, params: LayoutParams!)`
open Boolean	`arrowScroll(direction: Int)` Handle scrolling in response to an up or down arrow click.
open Unit	`computeScroll()`
open Boolean	`dispatchKeyEvent(event: KeyEvent!)`
open Boolean	`dispatchNestedFling(velocityX: Float, velocityY: Float, consumed: Boolean)`
open Boolean	`dispatchNestedPreFling(velocityX: Float, velocityY: Float)`
open Boolean	`dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?, type: Int)`
open Boolean	`dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?)`
open Unit	`dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, @Nullable offsetInWindow: IntArray?, type: Int, @NonNull consumed: IntArray)`
open Boolean	`dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, offsetInWindow: IntArray?, type: Int)`
open Boolean	`dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, offsetInWindow: IntArray?)`
open Unit	`draw(canvas: Canvas!)`
open Boolean	`executeKeyEvent(@NonNull event: KeyEvent)` You can call this function yourself to have the scroll view perform scrolling from a key event, just as if the event had been dispatched to it by the view hierarchy.
open Unit	`fling(velocityY: Int)` Fling the scroll view
open Boolean	`fullScroll(direction: Int)` Handles scrolling in response to a "home/end" shortcut press.
open Int	`getMaxScrollAmount()`
open Int	`getNestedScrollAxes()`
open Boolean	`hasNestedScrollingParent(type: Int)`
open Boolean	`hasNestedScrollingParent()`
open Boolean	`isFillViewport()` Indicates whether this ScrollView's content is stretched to fill the viewport.
open Boolean	`isNestedScrollingEnabled()`
open Boolean	`isSmoothScrollingEnabled()`
open Unit	`onAttachedToWindow()`
open Boolean	`onGenericMotionEvent(event: MotionEvent!)`
open Boolean	`onInterceptTouchEvent(ev: MotionEvent!)`
open Boolean	`onNestedFling(@NonNull target: View, velocityX: Float, velocityY: Float, consumed: Boolean)`
open Boolean	`onNestedPreFling(@NonNull target: View, velocityX: Float, velocityY: Float)`
open Unit	`onNestedPreScroll(@NonNull target: View, dx: Int, dy: Int, @NonNull consumed: IntArray, type: Int)`
open Unit	`onNestedPreScroll(@NonNull target: View, dx: Int, dy: Int, @NonNull consumed: IntArray)`
open Unit	`onNestedScroll(@NonNull target: View, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, type: Int, @NonNull consumed: IntArray)`
open Unit	`onNestedScroll(@NonNull target: View, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, type: Int)`
open Unit	`onNestedScroll(@NonNull target: View, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int)`
open Unit	`onNestedScrollAccepted(@NonNull child: View, @NonNull target: View, axes: Int, type: Int)`
open Unit	`onNestedScrollAccepted(@NonNull child: View, @NonNull target: View, nestedScrollAxes: Int)`
open Boolean	`onStartNestedScroll(@NonNull child: View, @NonNull target: View, axes: Int, type: Int)`
open Boolean	`onStartNestedScroll(@NonNull child: View, @NonNull target: View, nestedScrollAxes: Int)`
open Unit	`onStopNestedScroll(@NonNull target: View, type: Int)`
open Unit	`onStopNestedScroll(@NonNull target: View)`
open Boolean	`onTouchEvent(ev: MotionEvent!)`
open Boolean	`pageScroll(direction: Int)` Handles scrolling in response to a "page up/down" shortcut press.
open Unit	`requestChildFocus(child: View!, focused: View!)`
open Boolean	`requestChildRectangleOnScreen(child: View!, rectangle: Rect!, immediate: Boolean)`
open Unit	`requestDisallowInterceptTouchEvent(disallowIntercept: Boolean)`
open Unit	`requestLayout()`
open Unit	`scrollTo(x: Int, y: Int)` This version also clamps the scrolling to the bounds of our child.
open Unit	`setFillViewport(fillViewport: Boolean)` Set whether this ScrollView should stretch its content height to fill the viewport or not.
open Unit	`setNestedScrollingEnabled(enabled: Boolean)`
open Unit	`setOnScrollChangeListener(@Nullable l: NestedScrollView.OnScrollChangeListener?)` Register a callback to be invoked when the scroll X or Y positions of this view change.
open Unit	`setSmoothScrollingEnabled(smoothScrollingEnabled: Boolean)` Set whether arrow scrolling will animate its transition.
open Boolean	`shouldDelayChildPressedState()`
Unit	`smoothScrollBy(dx: Int, dy: Int)` Like `View#scrollBy`, but scroll smoothly instead of immediately.
Unit	`smoothScrollBy(dx: Int, dy: Int, scrollDurationMs: Int)` Like `View#scrollBy`, but scroll smoothly instead of immediately.
Unit	`smoothScrollTo(x: Int, y: Int)` Like `scrollTo`, but scroll smoothly instead of immediately.
Unit	`smoothScrollTo(x: Int, y: Int, scrollDurationMs: Int)` Like `scrollTo`, but scroll smoothly instead of immediately.
open Boolean	`startNestedScroll(axes: Int, type: Int)`
open Boolean	`startNestedScroll(axes: Int)`
open Unit	`stopNestedScroll(type: Int)`
open Unit	`stopNestedScroll()`

Protected methods
open Int	`computeScrollDeltaToGetChildRectOnScreen(rect: Rect!)` Compute the amount to scroll in the Y direction in order to get a rectangle completely on the screen (or, if taller than the screen, at least the first screen size chunk of it).
open Float	`getBottomFadingEdgeStrength()`
open Float	`getTopFadingEdgeStrength()`
open Unit	`measureChild(child: View!, parentWidthMeasureSpec: Int, parentHeightMeasureSpec: Int)`
open Unit	`measureChildWithMargins(child: View!, parentWidthMeasureSpec: Int, widthUsed: Int, parentHeightMeasureSpec: Int, heightUsed: Int)`
open Unit	`onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int)`
open Unit	`onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)`
open Unit	`onOverScrolled(scrollX: Int, scrollY: Int, clampedX: Boolean, clampedY: Boolean)`
open Boolean	`onRequestFocusInDescendants(direction: Int, previouslyFocusedRect: Rect!)` When looking for focus in children of a scroll view, need to be a little more careful not to give focus to something that is scrolled off screen.
open Unit	`onRestoreInstanceState(state: Parcelable!)`
open Parcelable?	`onSaveInstanceState()`
open Unit	`onScrollChanged(l: Int, t: Int, oldl: Int, oldt: Int)`
open Unit	`onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int)`

Public constructors

<init>

NestedScrollView(@NonNull context: Context)

<init>

NestedScrollView(
    @NonNull context: Context, 
    @Nullable attrs: AttributeSet?)

<init>

NestedScrollView(
    @NonNull context: Context, 
    @Nullable attrs: AttributeSet?, 
    defStyleAttr: Int)

Public methods

addView

open fun addView(child: View!): Unit

addView

open fun addView(
    child: View!, 
    index: Int
): Unit

addView

open fun addView(
    child: View!, 
    params: LayoutParams!
): Unit

addView

open fun addView(
    child: View!, 
    index: Int, 
    params: LayoutParams!
): Unit

arrowScroll

open fun arrowScroll(direction: Int): Boolean

Handle scrolling in response to an up or down arrow click.

Parameters
`direction`	Int: The direction corresponding to the arrow key that was pressed

Return
`Boolean`	True if we consumed the event, false otherwise

computeScroll

open fun computeScroll(): Unit

dispatchKeyEvent

open fun dispatchKeyEvent(event: KeyEvent!): Boolean

dispatchNestedFling

open fun dispatchNestedFling(
    velocityX: Float, 
    velocityY: Float, 
    consumed: Boolean
): Boolean

dispatchNestedPreFling

open fun dispatchNestedPreFling(
    velocityX: Float, 
    velocityY: Float
): Boolean

dispatchNestedPreScroll

open fun dispatchNestedPreScroll(
    dx: Int, 
    dy: Int, 
    consumed: IntArray?, 
    offsetInWindow: IntArray?, 
    type: Int
): Boolean

dispatchNestedPreScroll

open fun dispatchNestedPreScroll(
    dx: Int, 
    dy: Int, 
    consumed: IntArray?, 
    offsetInWindow: IntArray?
): Boolean

dispatchNestedScroll

open fun dispatchNestedScroll(
    dxConsumed: Int, 
    dyConsumed: Int, 
    dxUnconsumed: Int, 
    dyUnconsumed: Int, 
    @Nullable offsetInWindow: IntArray?, 
    type: Int, 
    @NonNull consumed: IntArray
): Unit

dispatchNestedScroll

open fun dispatchNestedScroll(
    dxConsumed: Int, 
    dyConsumed: Int, 
    dxUnconsumed: Int, 
    dyUnconsumed: Int, 
    offsetInWindow: IntArray?, 
    type: Int
): Boolean

dispatchNestedScroll

open fun dispatchNestedScroll(
    dxConsumed: Int, 
    dyConsumed: Int, 
    dxUnconsumed: Int, 
    dyUnconsumed: Int, 
    offsetInWindow: IntArray?
): Boolean

draw

open fun draw(canvas: Canvas!): Unit

executeKeyEvent

open fun executeKeyEvent(@NonNull event: KeyEvent): Boolean

You can call this function yourself to have the scroll view perform scrolling from a key event, just as if the event had been dispatched to it by the view hierarchy.

Parameters
`event`	KeyEvent: The key event to execute.

Return
`Boolean`	Return true if the event was handled, else false.

fling

open fun fling(velocityY: Int): Unit

Fling the scroll view

Parameters
`velocityY`	Int: The initial velocity in the Y direction. Positive numbers mean that the finger/cursor is moving down the screen, which means we want to scroll towards the top.

fullScroll

open fun fullScroll(direction: Int): Boolean

Handles scrolling in response to a "home/end" shortcut press. This method will scroll the view to the top or bottom and give the focus to the topmost/bottommost component in the new visible area. If no component is a good candidate for focus, this scrollview reclaims the focus.

Parameters
`direction`	Int: the scroll direction: `android.view.View#FOCUS_UP` to go the top of the view or `android.view.View#FOCUS_DOWN` to go the bottom

Return
`Boolean`	true if the key event is consumed by this method, false otherwise

getMaxScrollAmount

open fun getMaxScrollAmount(): Int

Return
`Int`	The maximum amount this scroll view will scroll in response to an arrow event.

getNestedScrollAxes

open fun getNestedScrollAxes(): Int

hasNestedScrollingParent

open fun hasNestedScrollingParent(type: Int): Boolean

hasNestedScrollingParent

open fun hasNestedScrollingParent(): Boolean

isFillViewport

open fun isFillViewport(): Boolean

Indicates whether this ScrollView's content is stretched to fill the viewport.

Return
`Boolean`	True if the content fills the viewport, false otherwise.

isNestedScrollingEnabled

open fun isNestedScrollingEnabled(): Boolean

isSmoothScrollingEnabled

open fun isSmoothScrollingEnabled(): Boolean

Return
`Boolean`	Whether arrow scrolling will animate its transition.

onAttachedToWindow

open fun onAttachedToWindow(): Unit

onGenericMotionEvent

open fun onGenericMotionEvent(event: MotionEvent!): Boolean

onInterceptTouchEvent

open fun onInterceptTouchEvent(ev: MotionEvent!): Boolean

onNestedFling

open fun onNestedFling(
    @NonNull target: View, 
    velocityX: Float, 
    velocityY: Float, 
    consumed: Boolean
): Boolean

onNestedPreFling

open fun onNestedPreFling(
    @NonNull target: View, 
    velocityX: Float, 
    velocityY: Float
): Boolean

onNestedPreScroll

open fun onNestedPreScroll(
    @NonNull target: View, 
    dx: Int, 
    dy: Int, 
    @NonNull consumed: IntArray, 
    type: Int
): Unit

onNestedPreScroll

open fun onNestedPreScroll(
    @NonNull target: View, 
    dx: Int, 
    dy: Int, 
    @NonNull consumed: IntArray
): Unit

onNestedScroll

open fun onNestedScroll(
    @NonNull target: View, 
    dxConsumed: Int, 
    dyConsumed: Int, 
    dxUnconsumed: Int, 
    dyUnconsumed: Int, 
    type: Int, 
    @NonNull consumed: IntArray
): Unit

onNestedScroll

open fun onNestedScroll(
    @NonNull target: View, 
    dxConsumed: Int, 
    dyConsumed: Int, 
    dxUnconsumed: Int, 
    dyUnconsumed: Int, 
    type: Int
): Unit

onNestedScroll

open fun onNestedScroll(
    @NonNull target: View, 
    dxConsumed: Int, 
    dyConsumed: Int, 
    dxUnconsumed: Int, 
    dyUnconsumed: Int
): Unit

onNestedScrollAccepted

open fun onNestedScrollAccepted(
    @NonNull child: View, 
    @NonNull target: View, 
    axes: Int, 
    type: Int
): Unit

onNestedScrollAccepted

open fun onNestedScrollAccepted(
    @NonNull child: View, 
    @NonNull target: View, 
    nestedScrollAxes: Int
): Unit

onStartNestedScroll

open fun onStartNestedScroll(
    @NonNull child: View, 
    @NonNull target: View, 
    axes: Int, 
    type: Int
): Boolean

onStartNestedScroll

open fun onStartNestedScroll(
    @NonNull child: View, 
    @NonNull target: View, 
    nestedScrollAxes: Int
): Boolean

onStopNestedScroll

open fun onStopNestedScroll(
    @NonNull target: View, 
    type: Int
): Unit

onStopNestedScroll

open fun onStopNestedScroll(@NonNull target: View): Unit

onTouchEvent

open fun onTouchEvent(ev: MotionEvent!): Boolean

pageScroll

open fun pageScroll(direction: Int): Boolean

Handles scrolling in response to a "page up/down" shortcut press. This method will scroll the view by one page up or down and give the focus to the topmost/bottommost component in the new visible area. If no component is a good candidate for focus, this scrollview reclaims the focus.

Parameters
`direction`	Int: the scroll direction: `android.view.View#FOCUS_UP` to go one page up or `android.view.View#FOCUS_DOWN` to go one page down

Return
`Boolean`	true if the key event is consumed by this method, false otherwise

requestChildFocus

open fun requestChildFocus(
    child: View!, 
    focused: View!
): Unit

requestChildRectangleOnScreen

open fun requestChildRectangleOnScreen(
    child: View!, 
    rectangle: Rect!, 
    immediate: Boolean
): Boolean

requestDisallowInterceptTouchEvent

open fun requestDisallowInterceptTouchEvent(disallowIntercept: Boolean): Unit

requestLayout

open fun requestLayout(): Unit

scrollTo

open fun scrollTo(
    x: Int, 
    y: Int
): Unit

This version also clamps the scrolling to the bounds of our child.

setFillViewport

open fun setFillViewport(fillViewport: Boolean): Unit

Set whether this ScrollView should stretch its content height to fill the viewport or not.

Parameters
`fillViewport`	Boolean: True to stretch the content's height to the viewport's boundaries, false otherwise.

setNestedScrollingEnabled

open fun setNestedScrollingEnabled(enabled: Boolean): Unit

setOnScrollChangeListener

open fun setOnScrollChangeListener(@Nullable l: NestedScrollView.OnScrollChangeListener?): Unit

This version of the method works on all versions of Android, back to API v4.

Parameters
`l`	NestedScrollView.OnScrollChangeListener?: The listener to notify when the scroll X or Y position changes.

See Also

setSmoothScrollingEnabled

open fun setSmoothScrollingEnabled(smoothScrollingEnabled: Boolean): Unit

Set whether arrow scrolling will animate its transition.

Parameters
`smoothScrollingEnabled`	Boolean: whether arrow scrolling will animate its transition

shouldDelayChildPressedState

open fun shouldDelayChildPressedState(): Boolean

smoothScrollBy

fun smoothScrollBy(
    dx: Int, 
    dy: Int
): Unit

Like View#scrollBy, but scroll smoothly instead of immediately.

Parameters
`dx`	Int: the number of pixels to scroll by on the X axis
`dy`	Int: the number of pixels to scroll by on the Y axis

smoothScrollBy

fun smoothScrollBy(
    dx: Int, 
    dy: Int, 
    scrollDurationMs: Int
): Unit

Like View#scrollBy, but scroll smoothly instead of immediately.

Parameters
`dx`	Int: the number of pixels to scroll by on the X axis
`dy`	Int: the number of pixels to scroll by on the Y axis
`scrollDurationMs`	Int: the duration of the smooth scroll operation in milliseconds

smoothScrollTo

fun smoothScrollTo(
    x: Int, 
    y: Int
): Unit

Like scrollTo, but scroll smoothly instead of immediately.

Parameters
`x`	Int: the position where to scroll on the X axis
`y`	Int: the position where to scroll on the Y axis

smoothScrollTo

fun smoothScrollTo(
    x: Int, 
    y: Int, 
    scrollDurationMs: Int
): Unit

Like scrollTo, but scroll smoothly instead of immediately.

Parameters
`x`	Int: the position where to scroll on the X axis
`y`	Int: the position where to scroll on the Y axis
`scrollDurationMs`	Int: the duration of the smooth scroll operation in milliseconds

startNestedScroll

open fun startNestedScroll(
    axes: Int, 
    type: Int
): Boolean

startNestedScroll

open fun startNestedScroll(axes: Int): Boolean

stopNestedScroll

open fun stopNestedScroll(type: Int): Unit

stopNestedScroll

open fun stopNestedScroll(): Unit

Protected methods

computeScrollDeltaToGetChildRectOnScreen

protected open fun computeScrollDeltaToGetChildRectOnScreen(rect: Rect!): Int

Compute the amount to scroll in the Y direction in order to get a rectangle completely on the screen (or, if taller than the screen, at least the first screen size chunk of it).

Parameters
`rect`	Rect!: The rect.

Return
`Int`	The scroll delta.

getBottomFadingEdgeStrength

protected open fun getBottomFadingEdgeStrength(): Float

getTopFadingEdgeStrength

protected open fun getTopFadingEdgeStrength(): Float

measureChild

protected open fun measureChild(
    child: View!, 
    parentWidthMeasureSpec: Int, 
    parentHeightMeasureSpec: Int
): Unit

measureChildWithMargins

protected open fun measureChildWithMargins(
    child: View!, 
    parentWidthMeasureSpec: Int, 
    widthUsed: Int, 
    parentHeightMeasureSpec: Int, 
    heightUsed: Int
): Unit

onLayout

protected open fun onLayout(
    changed: Boolean, 
    l: Int, 
    t: Int, 
    r: Int, 
    b: Int
): Unit

onMeasure

protected open fun onMeasure(
    widthMeasureSpec: Int, 
    heightMeasureSpec: Int
): Unit

onOverScrolled

protected open fun onOverScrolled(
    scrollX: Int, 
    scrollY: Int, 
    clampedX: Boolean, 
    clampedY: Boolean
): Unit

onRequestFocusInDescendants

protected open fun onRequestFocusInDescendants(
    direction: Int, 
    previouslyFocusedRect: Rect!
): Boolean

When looking for focus in children of a scroll view, need to be a little more careful not to give focus to something that is scrolled off screen. This is more expensive than the default android.view.ViewGroup implementation, otherwise this behavior might have been made the default.

onRestoreInstanceState

protected open fun onRestoreInstanceState(state: Parcelable!): Unit

onSaveInstanceState

protected open fun onSaveInstanceState(): Parcelable?

onScrollChanged

protected open fun onScrollChanged(
    l: Int, 
    t: Int, 
    oldl: Int, 
    oldt: Int
): Unit

onSizeChanged

protected open fun onSizeChanged(
    w: Int, 
    h: Int, 
    oldw: Int, 
    oldh: Int
): Unit