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Android APIs
public class

SparseArray

extends Object
implements Cloneable
java.lang.Object
   ↳ android.util.SparseArray<E>

Class Overview

SparseArrays map integers to Objects. Unlike a normal array of Objects, there can be gaps in the indices. It is intended to be more efficient than using a HashMap to map Integers to Objects.

Summary

Public Constructors
SparseArray()
Creates a new SparseArray containing no mappings.
SparseArray(int initialCapacity)
Creates a new SparseArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings.
Public Methods
void append(int key, E value)
Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array.
void clear()
Removes all key-value mappings from this SparseArray.
SparseArray<E> clone()
Creates and returns a copy of this Object.
void delete(int key)
Removes the mapping from the specified key, if there was any.
E get(int key)
Gets the Object mapped from the specified key, or null if no such mapping has been made.
E get(int key, E valueIfKeyNotFound)
Gets the Object mapped from the specified key, or the specified Object if no such mapping has been made.
int indexOfKey(int key)
Returns the index for which keyAt(int) would return the specified key, or a negative number if the specified key is not mapped.
int indexOfValue(E value)
Returns an index for which valueAt(int) would return the specified key, or a negative number if no keys map to the specified value.
int keyAt(int index)
Given an index in the range 0...size()-1, returns the key from the indexth key-value mapping that this SparseArray stores.
void put(int key, E value)
Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one.
void remove(int key)
Alias for delete(int).
void removeAt(int index)
Removes the mapping at the specified index.
void setValueAt(int index, E value)
Given an index in the range 0...size()-1, sets a new value for the indexth key-value mapping that this SparseArray stores.
int size()
Returns the number of key-value mappings that this SparseArray currently stores.
E valueAt(int index)
Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this SparseArray stores.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public SparseArray ()

Since: API Level 1

Creates a new SparseArray containing no mappings.

public SparseArray (int initialCapacity)

Since: API Level 1

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

Public Methods

public void append (int key, E value)

Since: API Level 1

Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array.

public void clear ()

Since: API Level 1

Removes all key-value mappings from this SparseArray.

public SparseArray<E> clone ()

Since: API Level 1

Creates and returns a copy of this Object. The default implementation returns a so-called "shallow" copy: It creates a new instance of the same class and then copies the field values (including object references) from this instance to the new instance. A "deep" copy, in contrast, would also recursively clone nested objects. A subclass that needs to implement this kind of cloning should call super.clone() to create the new instance and then create deep copies of the nested, mutable objects.

Returns
  • a copy of this object.

public void delete (int key)

Since: API Level 1

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

public E get (int key)

Since: API Level 1

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

public E get (int key, E valueIfKeyNotFound)

Since: API Level 1

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

public int indexOfKey (int key)

Since: API Level 1

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

public int indexOfValue (E value)

Since: API Level 1

Returns an index for which valueAt(int) 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.

public int keyAt (int index)

Since: API Level 1

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

public void put (int key, E value)

Since: API Level 1

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

public void remove (int key)

Since: API Level 1

Alias for delete(int).

public void removeAt (int index)

Since: API Level 11

Removes the mapping at the specified index.

public void setValueAt (int index, E value)

Since: API Level 1

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

public int size ()

Since: API Level 1

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

public E valueAt (int index)

Since: API Level 1

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