SparseArrayCompat
open class SparseArrayCompat<E : Any!> : Cloneable
kotlin.Any | |
↳ | androidx.collection.SparseArrayCompat |
SparseArrays map integers to Objects. Unlike a normal array of Objects, there can be gaps in the indices. It is intended to be more memory efficient than using a HashMap to map Integers to Objects, both because it avoids auto-boxing keys and its data structure doesn't rely on an extra entry object for each mapping.
Note that this container keeps its mappings in an array data structure, using a binary search to find keys. The implementation is not intended to be appropriate for data structures that may contain large numbers of items. It is generally slower than a traditional HashMap, since lookups require a binary search and adds and removes require inserting and deleting entries in the array. For containers holding up to hundreds of items, the performance difference is not significant, less than 50%.
To help with performance, the container includes an optimization when removing keys: instead of compacting its array immediately, it leaves the removed entry marked as deleted. The entry can then be re-used for the same key, or compacted later in a single garbage collection step of all removed entries. This garbage collection will need to be performed at any time the array needs to be grown or the the map size or entry values are retrieved.
It is possible to iterate over the items in this container using keyAt(int)
and valueAt(int)
. Iterating over the keys using keyAt(int)
with ascending values of the index will return the keys in ascending order, or the values corresponding to the keys in ascending order in the case of valueAt(int)
.
Summary
Public constructors | |
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<init>() Creates a new SparseArray containing no mappings. |
|
Creates a new SparseArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings. |
Public methods | |
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open Unit |
Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array. |
open Unit |
clear() Removes all key-value mappings from this SparseArray. |
open SparseArrayCompat<E> |
clone() |
open Boolean |
containsKey(key: Int) Returns true if the specified key is mapped. |
open Boolean |
containsValue(value: E) Returns true if the specified value is mapped from any key. |
open Unit | |
open E? |
Gets the Object mapped from the specified key, or |
open E |
Gets the Object mapped from the specified key, or the specified Object if no such mapping has been made. |
open Int |
indexOfKey(key: Int) Returns the index for which |
open Int |
indexOfValue(value: E) Returns an index for which |
open Boolean |
isEmpty() Return true if size() is 0. |
open Int |
Given an index in the range |
open Unit |
Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one. |
open Unit |
putAll(@NonNull other: SparseArrayCompat<out E>) Copies all of the mappings from the |
open E? |
putIfAbsent(key: Int, value: E) Add a new value to the array map only if the key does not already have a value or it is mapped to |
open Unit |
Removes the mapping from the specified key, if there was any. |
open Boolean |
Remove an existing key from the array map only if it is currently mapped to |
open Unit |
Removes the mapping at the specified index. |
open Unit |
removeAtRange(index: Int, size: Int) Remove a range of mappings as a batch. |
open E? |
Replace the mapping for |
open Boolean |
Replace the mapping for |
open Unit |
setValueAt(index: Int, value: E) Given an index in the range |
open Int |
size() Returns the number of key-value mappings that this SparseArray currently stores. |
open String |
toString() This implementation composes a string by iterating over its mappings. |
open E |
Given an index in the range |
Extension functions | ||||||||||||||||||||
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From androidx.collection
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Extension properties | ||
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From androidx.collection
|
Public constructors
<init>
SparseArrayCompat()
Creates a new SparseArray containing no mappings.
<init>
SparseArrayCompat(initialCapacity: Int)
Creates a new SparseArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings. If you supply an initial capacity of 0, the sparse array will be initialized with a light-weight representation not requiring any additional array allocations.
Public methods
append
open fun append(
key: Int,
value: E
): Unit
Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array.
clone
open fun clone(): SparseArrayCompat<E