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SortedList

open class SortedList<T : Any!>
kotlin.Any
   ↳ androidx.recyclerview.widget.SortedList

A Sorted list implementation that can keep items in order and also notify for changes in the list such that it can be bound to a RecyclerView.Adapter.

It keeps items ordered using the Callback#compare(Object, Object) method and uses binary search to retrieve items. If the sorting criteria of your items may change, make sure you call appropriate methods while editing them to avoid data inconsistencies.

You can control the order of items and change notifications via the Callback parameter.

Summary

Nested classes
open

A callback implementation that can batch notify events dispatched by the SortedList.

abstract

The class that controls the behavior of the SortedList.

Constants
static Int

Used by indexOf(Object) when the item cannot be found in the list.

Public constructors
<init>(@NonNull klass: Class<T>, @NonNull callback: SortedList.Callback<T>)

Creates a new SortedList of type T.

<init>(@NonNull klass: Class<T>, @NonNull callback: SortedList.Callback<T>, initialCapacity: Int)

Creates a new SortedList of type T.

Public methods
open Int
add(item: T)

Adds the given item to the list.

open Unit
addAll(@NonNull items: Array<T>, mayModifyInput: Boolean)

Adds the given items to the list.

open Unit
addAll(@NonNull vararg items: T)

Adds the given items to the list.

open Unit
addAll(@NonNull items: MutableCollection<T>)

Adds the given items to the list.

open Unit

Batches adapter updates that happen after calling this method and before calling endBatchedUpdates().

open Unit

Removes all items from the SortedList.

open Unit

Ends the update transaction and dispatches any remaining event to the callback.

open T
get(index: Int)

Returns the item at the given index.

open Int
indexOf(item: T)

Returns the position of the provided item.

open Unit

This method can be used to recalculate the position of the item at the given index, without triggering an Callback#onChanged(int, int) callback.

open Boolean
remove(item: T)

Removes the provided item from the list and calls Callback#onRemoved(int, int).

open T
removeItemAt(index: Int)

Removes the item at the given index and calls Callback#onRemoved(int, int).

open Unit
replaceAll(@NonNull items: Array<T>, mayModifyInput: Boolean)

Replaces the current items with the new items, dispatching ListUpdateCallback events for each change detected as appropriate.

open Unit
replaceAll(@NonNull vararg items: T)

Replaces the current items with the new items, dispatching ListUpdateCallback events for each change detected as appropriate.

open Unit
replaceAll(@NonNull items: MutableCollection<T>)

Replaces the current items with the new items, dispatching ListUpdateCallback events for each change detected as appropriate.

open Int

The number of items in the list.

open Unit
updateItemAt(index: Int, item: T)

Updates the item at the given index and calls Callback#onChanged(int, int) and/or Callback#onMoved(int, int) if necessary.

Constants

INVALID_POSITION

static val INVALID_POSITION: Int

Used by indexOf(Object) when the item cannot be found in the list.

Value: -1

Public constructors

<init>

SortedList(
    @NonNull klass: Class<T>,
    @NonNull callback: SortedList.Callback<T>)

Creates a new SortedList of type T.

Parameters
klass Class<T>: The class of the contents of the SortedList.
callback SortedList.Callback<T>: The callback that controls the behavior of SortedList.

<init>

SortedList(
    @NonNull klass: Class<T>,
    @NonNull callback: SortedList.Callback<T>,
    initialCapacity: Int)

Creates a new SortedList of type T.

Parameters
klass Class<T>: The class of the contents of the SortedList.
callback SortedList.Callback<T>: The callback that controls the behavior of SortedList.
initialCapacity Int: The initial capacity to hold items.

Public methods

add

open fun add(item: T): Int

Adds the given item to the list. If this is a new item, SortedList calls Callback#onInserted(int, int).

If the item already exists in the list and its sorting criteria is not changed, it is replaced with the existing Item. SortedList uses Callback#areItemsTheSame(Object, Object) to check if two items are the same item and uses Callback#areContentsTheSame(Object, Object) to decide whether it should call Callback#onChanged(int, int) or not. In both cases, it always removes the reference to the old item and puts the new item into the backing array even if Callback#areContentsTheSame(Object, Object) returns false.

If the sorting criteria of the item is changed, SortedList won't be able to find its duplicate in the list which will result in having a duplicate of the Item in the list. If you need to update sorting criteria of an item that already exists in the list, use updateItemAt(int, Object). You can find the index of the item using indexOf(Object) before you update the object.

Parameters
item T: The item to be added into the list.
Return
Int The index of the newly added item.

addAll

open fun addAll(
    @NonNull items: Array<T>,
    mayModifyInput: Boolean
): Unit

Adds the given items to the list. Equivalent to calling SortedList#add in a loop, except the callback events may be in a different order/granularity since addAll can batch them for better performance.

If allowed, will reference the input array during, and possibly after, the operation to avoid extra memory allocation, in which case you should not continue to reference or modify the array yourself.

Parameters
items Array<T>: Array of items to be added into the list.
mayModifyInput Boolean: If true, SortedList is allowed to modify and permanently reference the input array.

addAll

open fun addAll(@NonNull vararg items: T): Unit

Adds the given items to the list. Does not modify or retain the input.

Parameters
items T: Array of items to be added into the list.

addAll

open fun addAll(@NonNull items: MutableCollection<T>): Unit

Adds the given items to the list. Does not modify or retain the input.

Parameters
items MutableCollection<T>: Collection of items to be added into the list.

beginBatchedUpdates

open fun beginBatchedUpdates(): Unit