QAbstractEventDispatcher#
The QAbstractEventDispatcher
class provides an interface to manage Qt’s event queue. More…
Synopsis#
Functions#
def
filterNativeEvent
(eventType, message, result)def
installNativeEventFilter
(filterObj)def
registerTimer
(interval, timerType, object)def
removeNativeEventFilter
(filterObj)
Virtual functions#
def
closingDown
()def
interrupt
()def
processEvents
(flags)def
registerSocketNotifier
(notifier)def
registerTimer
(timerId, interval, timerType, object)def
registeredTimers
(object)def
remainingTime
(timerId)def
startingUp
()def
unregisterSocketNotifier
(notifier)def
unregisterTimer
(timerId)def
unregisterTimers
(object)def
wakeUp
()
Signals#
def
aboutToBlock
()def
awake
()
Static functions#
def
instance
([thread=None])
Note
This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE
Detailed Description#
An event dispatcher receives events from the window system and other sources. It then sends them to the QCoreApplication
or QApplication
instance for processing and delivery. QAbstractEventDispatcher
provides fine-grained control over event delivery.
For simple control of event processing use processEvents()
.
For finer control of the application’s event loop, call instance()
and call functions on the QAbstractEventDispatcher
object that is returned. If you want to use your own instance of QAbstractEventDispatcher
or of a QAbstractEventDispatcher
subclass, you must install it with setEventDispatcher()
or setEventDispatcher()
before a default event dispatcher has been installed.
The main event loop is started by calling exec()
, and stopped by calling exit()
. Local event loops can be created using QEventLoop
.
Programs that perform long operations can call processEvents()
with a bitwise OR combination of various ProcessEventsFlag
values to control which events should be delivered.
QAbstractEventDispatcher
also allows the integration of an external event loop with the Qt event loop.
See also
- class PySide6.QtCore.QAbstractEventDispatcher([parent=None])#
- Parameters:
parent –
PySide6.QtCore.QObject
Constructs a new event dispatcher with the given parent
.
- PySide6.QtCore.QAbstractEventDispatcher.aboutToBlock()#
This signal is emitted before the event loop calls a function that could block.
See also
- PySide6.QtCore.QAbstractEventDispatcher.awake()#
This signal is emitted after the event loop returns from a function that could block.
See also
- PySide6.QtCore.QAbstractEventDispatcher.closingDown()#
- PySide6.QtCore.QAbstractEventDispatcher.filterNativeEvent(eventType, message, result)#
- Parameters:
eventType –
PySide6.QtCore.QByteArray
message –
void
result –
qintptr
- Return type:
bool
Sends message
through the event filters that were set by installNativeEventFilter()
. This function returns true
as soon as an event filter returns true
, and false otherwise to indicate that the processing of the event should continue.
Subclasses of QAbstractEventDispatcher
must call this function for all messages received from the system to ensure compatibility with any extensions that may be used in the application. The type of event eventType
is specific to the platform plugin chosen at run-time, and can be used to cast message to the right type. The result
pointer is only used on Windows, and corresponds to the LRESULT pointer.
Note that the type of message
is platform dependent. See QAbstractNativeEventFilter
for details.
- PySide6.QtCore.QAbstractEventDispatcher.installNativeEventFilter(filterObj)#
- Parameters:
filterObj –
PySide6.QtCore.QAbstractNativeEventFilter
Installs an event filter filterObj
for all native events received by the application.
The event filter filterObj
receives events via its nativeEventFilter()
function, which is called for all events received by all threads.
The nativeEventFilter()
function should return true if the event should be filtered, (in this case, stopped). It should return false to allow normal Qt processing to continue: the native event can then be translated into a QEvent
and handled by the standard Qt event
filtering, e.g. installEventFilter()
.
If multiple event filters are installed, the filter that was installed last is activated first.
Note
The filter function set here receives native messages, that is, MSG or XEvent structs.
For maximum portability, you should always try to use QEvent
objects and installEventFilter()
whenever possible.
See also
- static PySide6.QtCore.QAbstractEventDispatcher.instance([thread=None])#
- Parameters:
thread –
PySide6.QtCore.QThread
- Return type:
Returns a pointer to the event dispatcher object for the specified thread
. If thread
is None
, the current thread is used. If no event dispatcher exists for the specified thread, this function returns None
.
Note
If Qt is built without thread support, the thread
argument is ignored.
- abstract PySide6.QtCore.QAbstractEventDispatcher.interrupt()#
Interrupts event dispatching. The event dispatcher will return from processEvents()
as soon as possible.
- abstract PySide6.QtCore.QAbstractEventDispatcher.processEvents(flags)#
- Parameters:
flags –
ProcessEventsFlags
- Return type:
bool
Processes pending events that match flags
until there are no more events to process. Returns true
if an event was processed; otherwise returns false
.
This function is especially useful if you have a long running operation, and want to show its progress without allowing user input by using the ExcludeUserInputEvents
flag.
If the WaitForMoreEvents
flag is set in flags
, the behavior of this function is as follows:
If events are available, this function returns after processing them.
If no events are available, this function will wait until more are available and return after processing newly available events.
If the WaitForMoreEvents
flag is not set in flags
, and no events are available, this function will return immediately.
Note
This function does not process events continuously; it returns after all available events are processed.
- abstract PySide6.QtCore.QAbstractEventDispatcher.registerSocketNotifier(notifier)#
- Parameters:
notifier –
PySide6.QtCore.QSocketNotifier
Registers notifier
with the event loop. Subclasses must implement this method to tie a socket notifier into another event loop.
- abstract PySide6.QtCore.QAbstractEventDispatcher.registerTimer(timerId, interval, timerType, object)#
- Parameters:
timerId – int
interval – int
timerType –
TimerType
object –
PySide6.QtCore.QObject
Register a timer with the specified timerId
, interval
, and timerType
for the given object
.
- PySide6.QtCore.QAbstractEventDispatcher.registerTimer(interval, timerType, object)
- Parameters:
interval – int
timerType –
TimerType
object –
PySide6.QtCore.QObject
- Return type:
int
Registers a timer with the specified interval
and timerType
for the given object
and returns the timer id.
- abstract PySide6.QtCore.QAbstractEventDispatcher.registeredTimers(object)#
- Parameters:
object –
PySide6.QtCore.QObject
- Return type:
Returns a list of registered timers for object
. The TimerInfo
struct has timerId
, interval
, and timerType
members.
See also
TimerType
- abstract PySide6.QtCore.QAbstractEventDispatcher.remainingTime(timerId)#
- Parameters:
timerId – int
- Return type:
int
Returns the remaining time in milliseconds with the given timerId
. If the timer is inactive, the returned value will be -1. If the timer is overdue, the returned value will be 0.
See also
TimerType
- PySide6.QtCore.QAbstractEventDispatcher.removeNativeEventFilter(filterObj)#
- Parameters:
filterObj –
PySide6.QtCore.QAbstractNativeEventFilter
Removes the event filter filter
from this object. The request is ignored if such an event filter has not been installed.
All event filters for this object are automatically removed when this object is destroyed.
It is always safe to remove an event filter, even during event filter filter activation (that is, even from within the nativeEventFilter()
function).
- PySide6.QtCore.QAbstractEventDispatcher.startingUp()#
- abstract PySide6.QtCore.QAbstractEventDispatcher.unregisterSocketNotifier(notifier)#
- Parameters:
notifier –
PySide6.QtCore.QSocketNotifier
Unregisters notifier
from the event dispatcher. Subclasses must reimplement this method to tie a socket notifier into another event loop. Reimplementations must call the base implementation.
- abstract PySide6.QtCore.QAbstractEventDispatcher.unregisterTimer(timerId)#
- Parameters:
timerId – int
- Return type:
bool
Unregisters the timer with the given timerId
. Returns true
if successful; otherwise returns false
.
See also
- abstract PySide6.QtCore.QAbstractEventDispatcher.unregisterTimers(object)#
- Parameters:
object –
PySide6.QtCore.QObject
- Return type:
bool
Unregisters all the timers associated with the given object
. Returns true
if all timers were successful removed; otherwise returns false
.
See also
- abstract PySide6.QtCore.QAbstractEventDispatcher.wakeUp()#
Wakes up the event loop.
See also