---
title: "NestedScrollConnection"
description: "Interface to connect to the nested scroll system.

Pass this connection to the [nestedScroll] modifier to participate in the nested scroll hierarchy
and to receive nested scroll events when they are dispatched by the scrolling child (scrolling
child - the element that actually receives scrolling events and dispatches them via
[NestedScrollDispatcher])."
type: "interface"
---

<div class='type'>Interface</div>


<a id='references'></a>

<div class='sourceset sourceset-common'>Common</div>



```kotlin
@JvmDefaultWithCompatibility
interface NestedScrollConnection
```


Interface to connect to the nested scroll system.

Pass this connection to the `nestedScroll` modifier to participate in the nested scroll hierarchy
and to receive nested scroll events when they are dispatched by the scrolling child (scrolling
child - the element that actually receives scrolling events and dispatches them via
`NestedScrollDispatcher`).


## Functions

```kotlin
fun onPreScroll(available: Offset, source: NestedScrollSource): Offset
```


Pre scroll event chain. Called by children to allow parents to consume a portion of a drag
event beforehand

#### Parameters

| | |
| --- | --- |
| available | the delta available to consume for pre scroll |
| source | the source of the scroll event |


#### Returns

| | |
| --- | --- |
|  | the amount this connection consumed |



```kotlin
fun onPostScroll(consumed: Offset, available: Offset, source: NestedScrollSource): Offset
```


Post scroll event pass. This pass occurs when the dispatching (scrolling) descendant made
their consumption and notifies ancestors with what's left for them to consume.

#### Parameters

| | |
| --- | --- |
| consumed | the amount that was consumed by all nested scroll nodes below the hierarchy |
| available | the amount of delta available for this connection to consume |
| source | source of the scroll |


#### Returns

| | |
| --- | --- |
|  | the amount that was consumed by this connection |



```kotlin
suspend fun onPreFling(available: Velocity): Velocity
```


Pre fling event chain. Called by children when they are about to perform fling to allow
parents to intercept and consume part of the initial velocity

#### Parameters

| | |
| --- | --- |
| available | the velocity which is available to pre consume and with which the child is about to fling |


#### Returns

| | |
| --- | --- |
|  | the amount this connection wants to consume and take from the child |



```kotlin
suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity
```


Post fling event chain. Called by the child when it is finished flinging (and sending
`onPreScroll` & `onPostScroll` events)

#### Parameters

| | |
| --- | --- |
| consumed | the amount of velocity consumed by the child |
| available | the amount of velocity left for a parent to fling after the child (if desired) |


#### Returns

| | |
| --- | --- |
|  | the amount of velocity consumed by the fling operation in this connection |