LruCache Class
Definition
Important
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A cache that holds strong references to a limited number of values.
[Android.Runtime.Register("android/util/LruCache", DoNotGenerateAcw=true)]
[Java.Interop.JavaTypeParameters(new System.String[] { "K", "V" })]
public class LruCache : Java.Lang.Object
[<Android.Runtime.Register("android/util/LruCache", DoNotGenerateAcw=true)>]
[<Java.Interop.JavaTypeParameters(new System.String[] { "K", "V" })>]
type LruCache = class
inherit Object
- Inheritance
- Attributes
Remarks
A cache that holds strong references to a limited number of values. Each time a value is accessed, it is moved to the head of a queue. When a value is added to a full cache, the value at the end of that queue is evicted and may become eligible for garbage collection.
If your cached values hold resources that need to be explicitly released, override #entryRemoved
.
If a cache miss should be computed on demand for the corresponding keys, override #create
. This simplifies the calling code, allowing it to assume a value will always be returned, even when there's a cache miss.
By default, the cache size is measured in the number of entries. Override #sizeOf
to size the cache in different units. For example, this cache is limited to 4MiB of bitmaps:
{@code
int cacheSize = 4 * 1024 * 1024; // 4MiB
LruCache<String, Bitmap> bitmapCache = new LruCache<String, Bitmap>(cacheSize) {
protected int sizeOf(String key, Bitmap value) {
return value.getByteCount();
}
}}
This class is thread-safe. Perform multiple cache operations atomically by synchronizing on the cache:
{@code
synchronized (cache) {
if (cache.get(key) == null) {
cache.put(key, value);
}
}}
This class does not allow null to be used as a key or value. A return value of null from #get
, #put
or #remove
is unambiguous: the key was not in the cache.
This class appeared in Android 3.1 (Honeycomb MR1); it's available as part of Android's Support Package for earlier releases.
Java documentation for android.util.LruCache
.
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
LruCache(Int32) | |
LruCache(IntPtr, JniHandleOwnership) |
A constructor used when creating managed representations of JNI objects; called by the runtime. |
Properties
Class |
Returns the runtime class of this |
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
Clone() |
Creates and returns a copy of this object. (Inherited from Object) |
Create(Object) |
Called after a cache miss to compute a value for the corresponding key. |
CreateCount() |
Returns the number of times |
Dispose() | (Inherited from Object) |
Dispose(Boolean) | (Inherited from Object) |
EntryRemoved(Boolean, Object, Object, Object) |
Called for entries that have been evicted or removed. |
Equals(Object) |
Indicates whether some other object is "equal to" this one. (Inherited from Object) |
EvictAll() |
Clear the cache, calling |
EvictionCount() |
Returns the number of values that have been evicted. |
Get(Object) |
Returns the value for |
GetHashCode() |
Returns a hash code value for the object. (Inherited from Object) |
HitCount() |
Returns the number of times |
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) |
MaxSize() |
For caches that do not override |
MissCount() |
Returns the number of times |
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(Object, Object) |
Caches |
PutCount() |
Returns the number of times |
Remove(Object) |
Removes the entry for |
Resize(Int32) |
Sets the size of the cache. |
SetHandle(IntPtr, JniHandleOwnership) |
Sets the Handle property. (Inherited from Object) |
Size() |
For caches that do not override |
SizeOf(Object, Object) |
Returns the size of the entry for |
Snapshot() |
Returns a copy of the current contents of the cache, ordered from least recently accessed to most recently accessed. |
ToArray<T>() | (Inherited from Object) |
ToString() |
Returns a string containing a concise, human-readable description of this object. |
TrimToSize(Int32) |
Remove the eldest entries until the total of remaining entries is at or below the requested size. |
UnregisterFromRuntime() | (Inherited from Object) |
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) |