recyclerview/androidx.recyclerview.widget/RecyclerView/State

State

Contains useful information about the current RecyclerView state like target scroll position or view focus. State object can also keep arbitrary data, identified by resource ids.

Often times, RecyclerView components will need to pass information between each other. To provide a well defined data bus between components, RecyclerView passes the same State object to component callbacks and these components can use it to exchange data.

If you implement custom components, you can use State's put/get/remove methods to pass data between your components without needing to manage their lifecycles.

Constructors

State

constructor()

Functions

didStructureChange

open fun didStructureChange(): Boolean

get

open fun <T> get(resourceId: Int): T

Gets the Object mapped from the specified id, or null if no such data exists.

getItemCount

open fun getItemCount(): Int

Returns the total number of items that can be laid out.

getRemainingScrollHorizontal

open fun getRemainingScrollHorizontal(): Int

Returns remaining horizontal scroll distance of an ongoing scroll animation(fling/ smoothScrollTo/SmoothScroller) in pixels.

getRemainingScrollVertical

open fun getRemainingScrollVertical(): Int

Returns remaining vertical scroll distance of an ongoing scroll animation(fling/ smoothScrollTo/SmoothScroller) in pixels.

getTargetScrollPosition

open fun getTargetScrollPosition(): Int

If scroll is triggered to make a certain item visible, this value will return the adapter index of that item.

hasTargetScrollPosition

open fun hasTargetScrollPosition(): Boolean

Returns if current scroll has a target position.

isMeasuring

open fun isMeasuring(): Boolean

Returns true if the RecyclerView is currently measuring the layout.

isPreLayout

open fun isPreLayout(): Boolean

Returns true if the RecyclerView is in the pre-layout step where it is having its LayoutManager layout items where they will be at the beginning of a set of predictive item animations.

put

open fun put(resourceId: Int, data: Any)

Adds a mapping from the specified id to the specified value, replacing the previous mapping from the specified key if there was one.

remove

open fun remove(resourceId: Int)

Removes the mapping from the specified id, if there was any.

toString

open fun toString(): String

willRunPredictiveAnimations

open fun willRunPredictiveAnimations(): Boolean

Returns whether RecyclerView will run predictive animations in this layout pass or not.

willRunSimpleAnimations

open fun willRunSimpleAnimations(): Boolean

Returns whether RecyclerView will run simple animations in this layout pass or not.