public
class
WifiManager.WifiLock
extends Object
| java.lang.Object | |
| ↳ | android.net.wifi.WifiManager.WifiLock |
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.
Any application using a WifiLock must request the android.permission.WAKE_LOCK
permission in an <uses-permission> element of the application's manifest.
Public methods | |
|---|---|
void
|
acquire()
Locks the Wi-Fi radio on until |
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 representation of the object. |
Protected methods | |
|---|---|
void
|
finalize()
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
Inherited methods | |
|---|---|
 From
class
java.lang.Object
| |
void acquire ()
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.
boolean isHeld ()
Checks whether this WifiLock is currently held.
| Returns | |
|---|---|
boolean |
true if this WifiLock is held, false otherwise |
void release ()
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.
void setReferenceCounted (boolean refCounted)
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 |
boolean:
true if this WifiLock should keep a reference count
|
String toString ()
Returns a string representation of the object. In general, the
toString method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
| Returns | |
|---|---|
String |
a string representation of the object. |
void finalize ()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
A subclass overrides the finalize method to dispose of
system resources or to perform other cleanup.
The general contract of finalize is that it is invoked
if and when the JavaTM virtual
machine has determined that there is no longer any
means by which this object can be accessed by any thread that has
not yet died, except as a result of an action taken by the
finalization of some other object or class which is ready to be
finalized. The finalize method may take any action, including
making this object available again to other threads; the usual purpose
of finalize, however, is to perform cleanup actions before
the object is irrevocably discarded. For example, the finalize method
for an object that represents an input/output connection might perform
explicit I/O transactions to break the connection before the object is
permanently discarded.
The finalize method of class Object performs no
special action; it simply returns normally. Subclasses of
Object may override this definition.
The Java programming language does not guarantee which thread will
invoke the finalize method for any given object. It is
guaranteed, however, that the thread that invokes finalize will not
be holding any user-visible synchronization locks when finalize is
invoked. If an uncaught exception is thrown by the finalize method,
the exception is ignored and finalization of that object terminates.
After the finalize method has been invoked for an object, no
further action is taken until the Java virtual machine has again
determined that there is no longer any means by which this object can
be accessed by any thread that has not yet died, including possible
actions by other objects or classes which are ready to be finalized,
at which point the object may be discarded.
The finalize method is never invoked more than once by a Java
virtual machine for any given object.
Any exception thrown by the finalize method causes
the finalization of this object to be halted, but is otherwise
ignored.
| Throws | |
|---|---|
Throwable |
|
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