ViewPager2.OnPageChangeCallback

abstract class ViewPager2.OnPageChangeCallback

Callback interface for responding to changing state of the selected page.

Summary

Public constructors

Public functions
Unit

Called when the scroll state changes.
Unit
onPageScrolled(
    position: Int,
    positionOffset: Float,
    positionOffsetPixels: @Px Int
)

This method will be invoked when the current page is scrolled, either as part of a programmatically initiated smooth scroll or a user initiated touch scroll.
Unit
onPageSelected(position: Int)

This method will be invoked when a new page becomes selected.

Public constructors

OnPageChangeCallback

Added in 1.0.0
OnPageChangeCallback()

Public functions

onPageScrollStateChanged

Added in 1.0.0
fun onPageScrollStateChanged(state: Int): Unit

Called when the scroll state changes. Useful for discovering when the user begins dragging, when a fake drag is started, when the pager is automatically settling to the current page, or when it is fully stopped/idle. state can be one of SCROLL_STATE_IDLE, SCROLL_STATE_DRAGGING or SCROLL_STATE_SETTLING.

onPageScrolled

Added in 1.0.0
fun onPageScrolled(
    position: Int,
    positionOffset: Float,
    positionOffsetPixels: @Px Int
): Unit

This method will be invoked when the current page is scrolled, either as part of a programmatically initiated smooth scroll or a user initiated touch scroll.

Parameters
position: Int

Position index of the first page currently being displayed. Page position+1 will be visible if positionOffset is nonzero.
positionOffset: Float

Value from [0, 1) indicating the offset from the page at position.
positionOffsetPixels: @Px Int

Value in pixels indicating the offset from position.

onPageSelected

Added in 1.0.0
fun onPageSelected(position: Int): Unit

This method will be invoked when a new page becomes selected. Animation is not necessarily complete.

Parameters
position: Int

Position index of the new selected page.