Added in API level 16

LongSparseArray


open class LongSparseArray<E : Any!> : Cloneable
kotlin.Any
   ↳ android.util.LongSparseArray

SparseArray mapping longs 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 Longs 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

Creates a new LongSparseArray containing no mappings.

LongSparseArray(initialCapacity: Int)

Creates a new LongSparseArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings.

Public methods
open Unit
append(key: Long, value: E)

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

Removes all key-value mappings from this LongSparseArray.

open LongSparseArray<E>

open Unit
delete(key: Long)

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

open E
get(key: Long)

Gets the Object mapped from the specified key, or null if no such mapping has been made.

open E
get(key: Long, valueIfKeyNotFound: E)

Gets the Object mapped from the specified key, or the specified Object if no such mapping has been made.

open Int

Returns the index for which keyAt would return the specified key, or a negative number if the specified key is not mapped.

open Int
indexOfValue(value: E)

Returns an index for which valueAt would return the specified key, or a negative number if no keys map to the specified value.

open Long
keyAt(index: Int)

Given an index in the range 0...size()-1, returns the key from the indexth key-value mapping that this LongSparseArray stores.

open Unit
put(key: Long, value: E)

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
remove(key: Long)

Alias for delete(long).

open Unit
removeAt(index: Int)

Removes the mapping at the specified index.

open Unit
setValueAt(index: Int, value: E)

Given an index in the range 0...size()-1, sets a new value for the indexth key-value mapping that this LongSparseArray stores.

open Int

Returns the number of key-value mappings that this LongSparseArray currently stores.

open String

Returns a string representation of the object.

open E
valueAt(index: Int)

Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this LongSparseArray stores.

Public constructors

LongSparseArray

Added in API level 16
LongSparseArray()

Creates a new LongSparseArray containing no mappings.

LongSparseArray

Added in API level 16
LongSparseArray(initialCapacity: Int)

Creates a new LongSparseArray 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

Added in API level 16
open fun append(
    key: Long,
    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.

clear

Added in API level 16
open fun clear(): Unit

Removes all key-value mappings from this LongSparseArray.

clone

Added in API level 16
open fun clone(): LongSparseArray<E>
Return
LongSparseArray<E> a clone of this instance.
Exceptions
java.lang.CloneNotSupportedException if the object's class does not support the Cloneable interface. Subclasses that override the clone method can also throw this exception to indicate that an instance cannot be cloned.

delete

Added in API level 16
open fun delete(key: Long): Unit

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

get

Added in API level 16
open fun get(key: Long): E

Gets the Object mapped from the specified key, or null if no such mapping has been made.

get

Added in API level 16
open fun get(
    key: Long,
    valueIfKeyNotFound: E
): E

Gets the Object mapped from the specified key, or the specified Object if no such mapping has been made.

indexOfKey

Added in API level 16
open fun indexOfKey(key: Long): Int

Returns the index for which keyAt would return the specified key, or a negative number if the specified key is not mapped.

indexOfValue

Added in API level 16
open fun indexOfValue(value: E): Int

Returns an index for which valueAt would return the specified key, or a negative number if no keys map to the specified value. Beware that this is a linear search, unlike lookups by key, and that multiple keys can map to the same value and this will find only one of them.

keyAt

Added in API level 16
open fun keyAt(index: Int): Long

Given an index in the range 0...size()-1, returns the key from the indexth key-value mapping that this LongSparseArray stores.

The keys corresponding to indices in ascending order are guaranteed to be in ascending order, e.g., keyAt(0) will return the smallest key and keyAt(size()-1) will return the largest key.

For indices outside of the range 0...size()-1, the behavior is undefined for apps targeting android.os.Build.VERSION_CODES#P and earlier, and an ArrayIndexOutOfBoundsException is thrown for apps targeting android.os.Build.VERSION_CODES#Q and later.

put

Added in API level 16
open fun put(
    key: Long,
    value: E
): Unit

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

remove

Added in API level 16
open fun remove(key: Long): Unit

Alias for delete(long).

removeAt

Added in API level 16
open fun removeAt(index: Int): Unit

Removes the mapping at the specified index.

For indices outside of the range 0...size()-1, the behavior is undefined for apps targeting android.os.Build.VERSION_CODES#P and earlier, and an ArrayIndexOutOfBoundsException is thrown for apps targeting android.os.Build.VERSION_CODES#Q and later.

setValueAt

Added in API level 16
open fun setValueAt(
    index: Int,
    value: E
): Unit

Given an index in the range 0...size()-1, sets a new value for the indexth key-value mapping that this LongSparseArray stores.

For indices outside of the range 0...size()-1, the behavior is undefined for apps targeting android.os.Build.VERSION_CODES#P and earlier, and an ArrayIndexOutOfBoundsException is thrown for apps targeting android.os.Build.VERSION_CODES#Q and later.

size

Added in API level 16
open fun size(): Int

Returns the number of key-value mappings that this LongSparseArray currently stores.

toString

Added in API level 16
open fun toString(): String

Returns a string representation of the object.

This implementation composes a string by iterating over its mappings. If this map contains itself as a value, the string "(this Map)" will appear in its place.

Return
String a string representation of the object.

valueAt

Added in API level 16
open fun valueAt(index: Int): E

Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this LongSparseArray stores.

The values corresponding to indices in ascending order are guaranteed to be associated with keys in ascending order, e.g., valueAt(0) will return the value associated with the smallest key and valueAt(size()-1) will return the value associated with the largest key.

For indices outside of the range 0...size()-1, the behavior is undefined for apps targeting android.os.Build.VERSION_CODES#P and earlier, and an ArrayIndexOutOfBoundsException is thrown for apps targeting android.os.Build.VERSION_CODES#Q and later.