SubcomposeSlotReusePolicy

public interface SubcomposeSlotReusePolicy

This policy allows SubcomposeLayout to retain some of slots which we were used but not used anymore instead of disposing them. Next time when you try to compose a new slot instead of creating a completely new slot the layout would reuse the kept slot. This allows to do less work especially if the slot contents are similar.

Functions

getSlotsToRetain

public fun getSlotsToRetain(slotIds: SlotIdsSet)

This function will be called with slotIds set populated with the slot ids available to reuse. In the implementation you can remove slots you don't want to retain.

areCompatible

public fun areCompatible(slotId: Any?, reusableSlotId: Any?): Boolean

Returns true if the content previously composed with reusableSlotId is compatible with the content which is going to be composed for slotId. Slots could be considered incompatible if they display completely different types of the UI.

Members

SlotIdsSet

public class SlotIdsSet internal constructor(
        internal val set: MutableOrderedScatterSet<Any?> = mutableOrderedScatterSetOf()
    ) : Collection<Any?>

Set containing slot ids currently available to reuse. Used by getSlotsToRetain. The set retains the insertion order of its elements, guaranteeing stable iteration order.

This class works exactly as MutableSet, but doesn't allow to add new items in it.

Properties

size

public override val size: Int

Functions

remove

public fun remove(slotId: Any?): Boolean

Removes a slotId from this set, if it is present.

Return

true if the slot id was removed, false if the set was not modified.

removeAll

public fun removeAll(slotIds: Collection<Any?>): Boolean

Removes all slot ids from slotIds that are also contained in this set.

Return

true if any slot id was removed, false if the set was not modified.

removeAll

public fun removeAll(predicate: (Any?) -> Boolean): Boolean

Removes all slot ids that match the given predicate.

Return

true if any slot id was removed, false if the set was not modified.

retainAll

public fun retainAll(slotIds: Collection<Any?>): Boolean

Retains only the slot ids that are contained in slotIds.

Return

true if any slot id was removed, false if the set was not modified.

retainAll

public fun retainAll(predicate: (Any?) -> Boolean): Boolean

Retains only slotIds that match the given predicate.

Return

true if any slot id was removed, false if the set was not modified.

clear

public fun clear(): Unit

Removes all slot ids from this set.

trimToSize

public fun trimToSize(maxSlotsToRetainForReuse: Int): Unit

Remove entries until size equals maxSlotsToRetainForReuse. Entries inserted last are removed first.

forEach

public fun forEach(block: (Any?) -> Unit): Unit

Iterates over every element stored in this set by invoking the specified block lambda. The iteration order is the same as the insertion order. It is safe to remove the element passed to block during iteration.

NOTE: This method is obscured by Collection<T>.forEach since it is marked with

fastForEach

public inline fun fastForEach(block: (Any?) -> Unit): Unit

Iterates over every element stored in this set by invoking the specified block lambda. The iteration order is the same as the insertion order. It is safe to remove the element passed to block during iteration.

NOTE: this method was added in order to allow for a more performant forEach method. It is necessary because forEach is obscured by Collection<T>.forEach since it is marked with @HidesMember.