public class

WifiManager.WifiLock

extends Object
java.lang.Object
   ↳ android.net.wifi.WifiManager.WifiLock

Class Overview

Allows an application to keep the Wi-Fi radio awake. Normally the Wi-Fi radio may turn off when the user has not used the device in a while. Acquiring a WifiLock will keep the radio on until the lock is released. Multiple applications may hold WifiLocks, and the radio will only be allowed to turn off when no WifiLocks are held in any application. Before using a WifiLock, consider carefully if your application requires Wi-Fi access, or could function over a mobile network, if available. A program that needs to download large files should hold a WifiLock to ensure that the download will complete, but a program whose network usage is occasional or low-bandwidth should not hold a WifiLock to avoid adversely affecting battery life. Note that WifiLocks cannot override the user-level "Wi-Fi Enabled" setting, nor Airplane Mode. They simply keep the radio from turning off when Wi-Fi is already on but the device is idle.

Summary

Public Methods
void acquire()
Locks the Wi-Fi radio on until release() is called.
boolean isHeld()
Checks whether this WifiLock is currently held.
void release()
Unlocks the Wi-Fi radio, allowing it to turn off when the device is idle.
void setReferenceCounted(boolean refCounted)
Controls whether this is a reference-counted or non-reference-counted WifiLock.
void setWorkSource(WorkSource ws)
String toString()
Returns a string containing a concise, human-readable description of this object.
Protected Methods
void finalize()
Called before the object's memory is reclaimed by the VM.
[Expand]
Inherited Methods
From class java.lang.Object

Public Methods

public void acquire ()

Since: API Level 1

Locks the Wi-Fi radio on until release() is called. If this WifiLock is reference-counted, each call to acquire will increment the reference count, and the radio will remain locked as long as the reference count is above zero. If this WifiLock is not reference-counted, the first call to acquire will lock the radio, but subsequent calls will be ignored. Only one call to release() will be required, regardless of the number of times that acquire is called.

public boolean isHeld ()

Since: API Level 1

Checks whether this WifiLock is currently held.

Returns
  • true if this WifiLock is held, false otherwise

public void release ()

Since: API Level 1

Unlocks the Wi-Fi radio, allowing it to turn off when the device is idle. If this WifiLock is reference-counted, each call to release will decrement the reference count, and the radio will be unlocked only when the reference count reaches zero. If the reference count goes below zero (that is, if release is called a greater number of times than acquire()), an exception is thrown. If this WifiLock is not reference-counted, the first call to release (after the radio was locked using acquire()) will unlock the radio, and subsequent calls will be ignored.

public void setReferenceCounted (boolean refCounted)

Since: API Level 1

Controls whether this is a reference-counted or non-reference-counted WifiLock. Reference-counted WifiLocks keep track of the number of calls to acquire() and release(), and only allow the radio to sleep when every call to acquire() has been balanced with a call to release(). Non-reference-counted WifiLocks lock the radio whenever acquire() is called and it is unlocked, and unlock the radio whenever release() is called and it is locked.

Parameters
refCounted true if this WifiLock should keep a reference count

public void setWorkSource (WorkSource ws)

Since: API Level 9

public String toString ()

Since: API Level 1

Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression:

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

See Writing a useful toString method if you intend implementing your own toString method.

Returns
  • a printable representation of this object.

Protected Methods

protected void finalize ()

Since: API Level 1

Called before the object's memory is reclaimed by the VM. This can only happen once the garbage collector has detected that the object is no longer reachable by any thread of the running application.

The method can be used to free system resources or perform other cleanup before the object is garbage collected. The default implementation of the method is empty, which is also expected by the VM, but subclasses can override finalize() as required. Uncaught exceptions which are thrown during the execution of this method cause it to terminate immediately but are otherwise ignored.

Note that the VM does guarantee that finalize() is called at most once for any object, but it doesn't guarantee when (if at all) finalize() will be called. For example, object B's finalize() can delay the execution of object A's finalize() method and therefore it can delay the reclamation of A's memory. To be safe, use a ReferenceQueue, because it provides more control over the way the VM deals with references during garbage collection.

Throws
Throwable