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Added in API level 12

Summary: Ctors | Methods | Protected Methods | Inherited Methods | [Expand All]

LruCache

public class LruCache
extends Object

java.lang.Object
↳	android.util.LruCache<K, V>

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(boolean, K, V, V).

If a cache miss should be computed on demand for the corresponding keys, override create(K). 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(K, V) to size the cache in different units. For example, this cache is limited to 4MiB of bitmaps:

   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:

   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(K), put(K, V) or remove(K) 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.

Summary

Public constructors
`LruCache(int maxSize)`

Public methods
`final int`	`createCount()` Returns the number of times `create(Object)` returned a value.
`final void`	`evictAll()` Clear the cache, calling `entryRemoved(boolean, K, V, V)` on each removed entry.
`final int`	`evictionCount()` Returns the number of values that have been evicted.
`final V`	`get(K key)` Returns the value for `key` if it exists in the cache or can be created by `#create`.
`final int`	`hitCount()` Returns the number of times `get(K)` returned a value that was already present in the cache.
`final int`	`maxSize()` For caches that do not override `sizeOf(K, V)`, this returns the maximum number of entries in the cache.
`final int`	`missCount()` Returns the number of times `get(K)` returned null or required a new value to be created.
`final V`	`put(K key, V value)` Caches `value` for `key`.
`final int`	`putCount()` Returns the number of times `put(K, V)` was called.
`final V`	`remove(K key)` Removes the entry for `key` if it exists.
`void`	`resize(int maxSize)` Sets the size of the cache.
`final int`	`size()` For caches that do not override `sizeOf(K, V)`, this returns the number of entries in the cache.
`final Map<K, V>`	`snapshot()` Returns a copy of the current contents of the cache, ordered from least recently accessed to most recently accessed.
`final String`	`toString()` Returns a string representation of the object.
`void`	`trimToSize(int maxSize)` Remove the eldest entries until the total of remaining entries is at or below the requested size.

Protected methods
`V`	`create(K key)` Called after a cache miss to compute a value for the corresponding key.
`void`	`entryRemoved(boolean evicted, K key, V oldValue, V newValue)` Called for entries that have been evicted or removed.
`int`	`sizeOf(K key, V value)` Returns the size of the entry for `key` and `value` in user-defined units.

Inherited methods

From class


  
    java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long millis, int nanos)` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
`final void`	`wait(long millis)` Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
`final void`	`wait()` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.

Parameters
`evicted`	`boolean`: true if the entry is being removed to make space, false if the removal was caused by a `put(K, V)` or `remove(K)`.
`key`	`K`
`oldValue`	`V`
`newValue`	`V`: the new value for `key`, if it exists. If non-null, this removal was caused by a `put(K, V)`. Otherwise it was caused by an eviction or a `remove(K)`.

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Results for

LruCache

Summary

Public constructors

Public methods

Protected methods

Inherited methods

Public constructors

LruCache

Public methods

createCount

evictAll

evictionCount

get

hitCount

maxSize

missCount

put

putCount

remove

resize

size

snapshot

toString

trimToSize

Protected methods

create

entryRemoved

sizeOf