ViewPager2.OnPageChangeCallback

public abstract class ViewPager2.OnPageChangeCallback

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

Summary

Public constructors

Public methods
void

Called when the scroll state changes.
void
onPageScrolled(
    int position,
    float positionOffset,
    @Px int positionOffsetPixels
)

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.
void
onPageSelected(int position)

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

Public constructors

OnPageChangeCallback

Added in 1.0.0
public OnPageChangeCallback()

Public methods

onPageScrollStateChanged

Added in 1.0.0
public void onPageScrollStateChanged(int state)

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
public void onPageScrolled(
    int position,
    float positionOffset,
    @Px int positionOffsetPixels
)

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
int position

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

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

Value in pixels indicating the offset from position.

onPageSelected

Added in 1.0.0
public void onPageSelected(int position)

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

Parameters
int position

Position index of the new selected page.