SparseArray Class

Reference

Definition

Namespace:: Android.Util

Assembly:: Mono.Android.dll

Important

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SparseArray maps integers to Objects and, unlike a normal array of Objects, its indices can contain gaps.

[Android.Runtime.Register("android/util/SparseArray", DoNotGenerateAcw=true)]
[Java.Interop.JavaTypeParameters(new System.String[] { "E" })]
public class SparseArray : Java.Lang.Object, IDisposable, Java.Interop.IJavaPeerable, Java.Lang.ICloneable

[<Android.Runtime.Register("android/util/SparseArray", DoNotGenerateAcw=true)>]
[<Java.Interop.JavaTypeParameters(new System.String[] { "E" })>]
type SparseArray = class
    inherit Object
    interface ICloneable
    interface IJavaObject
    interface IDisposable
    interface IJavaPeerable

Inheritance: Object

Object
SparseArray

Derived: Android.Util.SparseArray<E>

Attributes: RegisterAttribute JavaTypeParametersAttribute

Implements: IJavaObject IJavaPeerable ICloneable IDisposable

Remarks

SparseArray maps integers to Objects and, unlike a normal array of Objects, its indices can contain gaps. SparseArray is intended to be more memory-efficient than a <c>HashMap</c>, 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 HashMap because 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 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 of all removed entries. This garbage collection must be performed whenever the array needs to be grown, or when 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 returns the keys in ascending order. In the case of valueAt(int), the values corresponding to the keys are returned in ascending order.

Java documentation for android.util.SparseArray.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Constructors

SparseArray()	Creates a new SparseArray containing no mappings.
SparseArray(Int32)	Creates a new SparseArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings.
SparseArray(IntPtr, JniHandleOwnership)	A constructor used when creating managed representations of JNI objects; called by the runtime.

Properties

Class	Returns the runtime class of this `Object`. (Inherited from Object)
Handle	The handle to the underlying Android instance. (Inherited from Object)
JniIdentityHashCode	(Inherited from Object)
JniPeerMembers
PeerReference	(Inherited from Object)
ThresholdClass	This API supports the Mono for Android infrastructure and is not intended to be used directly from your code.
ThresholdType	This API supports the Mono for Android infrastructure and is not intended to be used directly from your code.

Methods

Append(Int32, Object)	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()	Removes all key-value mappings from this SparseArray.
Clone()	Creates and returns a copy of this `Object`.
Contains(Int32)	Returns true if the key exists in the array.
ContentEquals(SparseArray)	Compares the contents of this `SparseArray` to the specified `SparseArray`.
ContentHashCode()	Returns a hash code value for the contents of this `SparseArray`, combining the `Objects#hashCode(Object)` result of all its keys and values.
Delete(Int32)	Removes the mapping from the specified key, if there was any.
Dispose()	(Inherited from Object)
Dispose(Boolean)	(Inherited from Object)
Equals(Object)	Indicates whether some other object is "equal to" this one. (Inherited from Object)
Get(Int32)	Gets the Object mapped from the specified key, or `null` if no such mapping has been made.
Get(Int32, Object)	Gets the Object mapped from the specified key, or the specified Object if no such mapping has been made.
GetHashCode()	Returns a hash code value for the object. (Inherited from Object)
IndexOfKey(Int32)	Returns the index for which `#keyAt` would return the specified key, or a negative number if the specified key is not mapped.
IndexOfValue(Object)	Returns an index for which `#valueAt` would return the specified value, or a negative number if no keys map to the specified value.
JavaFinalize()	Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. (Inherited from Object)
KeyAt(Int32)	Given an index in the range `0...size()-1`, returns the key from the `index`th key-value mapping that this SparseArray stores.
Notify()	Wakes up a single thread that is waiting on this object's monitor. (Inherited from Object)
NotifyAll()	Wakes up all threads that are waiting on this object's monitor. (Inherited from Object)
Put(Int32, Object)	Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one.
Remove(Int32)	Alias for `#delete(int)`.
RemoveAt(Int32)	Removes the mapping at the specified index.
RemoveAtRange(Int32, Int32)	Remove a range of mappings as a batch.
Set(Int32, Object)	Alias for `#put(int, Object)` to support Kotlin [index]= operator.
SetHandle(IntPtr, JniHandleOwnership)	Sets the Handle property. (Inherited from Object)
SetValueAt(Int32, Object)	Given an index in the range `0...size()-1`, sets a new value for the `index`th key-value mapping that this SparseArray stores.
Size()	Returns the number of key-value mappings that this SparseArray currently stores.
ToArray<T>()	(Inherited from Object)
ToString()	Returns a string representation of the object. (Inherited from Object)
UnregisterFromRuntime()	(Inherited from Object)
ValueAt(Int32)	Given an index in the range `0...size()-1`, returns the value from the `index`th key-value mapping that this SparseArray stores.
Wait()	Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>. (Inherited from Object)
Wait(Int64)	Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed. (Inherited from Object)
Wait(Int64, Int32)	Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed. (Inherited from Object)

Explicit Interface Implementations

IJavaPeerable.Disposed()	(Inherited from Object)
IJavaPeerable.DisposeUnlessReferenced()	(Inherited from Object)
IJavaPeerable.Finalized()	(Inherited from Object)
IJavaPeerable.JniManagedPeerState	(Inherited from Object)
IJavaPeerable.SetJniIdentityHashCode(Int32)	(Inherited from Object)
IJavaPeerable.SetJniManagedPeerState(JniManagedPeerStates)	(Inherited from Object)
IJavaPeerable.SetPeerReference(JniObjectReference)	(Inherited from Object)

Extension Methods

JavaCast<TResult>(IJavaObject)	Performs an Android runtime-checked type conversion.
JavaCast<TResult>(IJavaObject)
GetJniTypeName(IJavaPeerable)

Applies to