SparseBooleanArray

open class SparseBooleanArray : Cloneable
kotlin.Any
   ↳ android.util.SparseBooleanArray

SparseBooleanArrays map integers to booleans. Unlike a normal array of booleans there can be gaps in the indices. It is intended to be more memory efficient than using a HashMap to map Integers to Booleans, both because it avoids auto-boxing keys and values 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%.

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 SparseBooleanArray containing no mappings.

<init>(initialCapacity: Int)

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

Public methods
open Int

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

open Int

open Unit

Removes all key-value mappings from this SparseBooleanArray.

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 Unit
put(key: Int, value: Boolean)

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

open Boolean
equals(other: Any?)

open Unit
removeAt(index: Int)

Removes the mapping at the specified index.

open String

Returns a string representation of the object.

open Boolean
valueAt(index: Int)

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

open Int
keyAt(index: Int)

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

open Unit
append(key: Int, value: Boolean)

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 SparseBooleanArray

open Int

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

open Boolean
get(key: Int)

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

open Boolean
get(key: Int, valueIfKeyNotFound: Boolean)

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

open Unit
delete(key: Int)

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

Public constructors

<init>

SparseBooleanArray()

Creates a new SparseBooleanArray containing no mappings.

<init>

SparseBooleanArray(initialCapacity: Int)

Creates a new SparseBooleanArray 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

indexOfValue

open fun indexOfValue(value: Boolean): 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.

hashCode

open fun hashCode(): Int

clear

open fun clear(): Unit

Removes all key-value mappings from this SparseBooleanArray.

indexOfKey

open fun indexOfKey(key: Int): Int

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

put

open fun put(key: Int, value: Boolean): Unit

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

equals

open fun equals(other: Any?): Boolean

removeAt

added in API level 28
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.
Requires API level 28 (Android 8.+, P)

toString

open fun toString(): String

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode()) 

This implementation composes a string by iterating over its mappings.

Return
String: a string representation of the object.

valueAt

open fun valueAt(index: Int): Boolean

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

keyAt

open fun keyAt(index: Int): Int

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

append

open fun append(key: Int, value: Boolean): 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(): SparseBooleanArray

size

open fun size(): Int

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

get

open fun get(key: Int): Boolean

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

get

open fun get(key: Int, valueIfKeyNotFound: Boolean): Boolean

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

delete

open fun delete(key: Int): Unit

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