public
final
class
PowerManager.WakeLock
extends Object
| java.lang.Object | |
| ↳ | android.os.PowerManager.WakeLock |
A wake lock is a mechanism to indicate that your application needs to have the device stay on.
Any application using a WakeLock must request the android.permission.WAKE_LOCK
permission in an <uses-permission> element of the application's manifest.
Obtain a wake lock by calling newWakeLock(int, String).
Call acquire() to acquire the wake lock and force the device to stay
on at the level that was requested when the wake lock was created.
Call release() when you are done and don't need the lock anymore.
It is very important to do this as soon as possible to avoid running down the
device's battery excessively.
Public methods | |
|---|---|
void
|
acquire()
Acquires the wake lock. |
void
|
acquire(long timeout)
Acquires the wake lock with a timeout. |
boolean
|
isHeld()
Returns true if the wake lock has been acquired but not yet released. |
void
|
release(int flags)
Releases the wake lock with flags to modify the release behavior. |
void
|
release()
Releases the wake lock. |
void
|
setReferenceCounted(boolean value)
Sets whether this WakeLock is reference counted. |
void
|
setWorkSource(WorkSource ws)
Sets the work source associated with the wake lock. |
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 ()
Acquires the wake lock.
Ensures that the device is on at the level requested when the wake lock was created.
void acquire (long timeout)
Acquires the wake lock with a timeout.
Ensures that the device is on at the level requested when the wake lock was created. The lock will be released after the given timeout expires.
| Parameters | |
|---|---|
timeout |
long:
The timeout after which to release the wake lock, in milliseconds.
|
boolean isHeld ()
Returns true if the wake lock has been acquired but not yet released.
| Returns | |
|---|---|
boolean |
True if the wake lock is held. |
void release (int flags)
Releases the wake lock with flags to modify the release behavior.
This method releases your claim to the CPU or screen being on. The screen may turn off shortly after you release the wake lock, or it may not if there are other wake locks still held.
| Parameters | |
|---|---|
flags |
int:
Combination of flag values to modify the release behavior.
Currently only RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY is supported.
Passing 0 is equivalent to calling release().
|
void release ()
Releases the wake lock.
This method releases your claim to the CPU or screen being on. The screen may turn off shortly after you release the wake lock, or it may not if there are other wake locks still held.
void setReferenceCounted (boolean value)
Sets whether this WakeLock is reference counted.
Wake locks are reference counted by default. If a wake lock is
reference counted, then each call to acquire() must be
balanced by an equal number of calls to release(). If a wake
lock is not reference counted, then one call to release() is
sufficient to undo the effect of all previous calls to acquire().
| Parameters | |
|---|---|
value |
boolean:
True to make the wake lock reference counted, false to
make the wake lock non-reference counted.
|
void setWorkSource (WorkSource ws)
Sets the work source associated with the wake lock.
The work source is used to determine on behalf of which application the wake lock is being held. This is useful in the case where a service is performing work on behalf of an application so that the cost of that work can be accounted to the application.
| Parameters | |
|---|---|
ws |
WorkSource:
The work source, or null if none.
|
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 |
|
Developers