• Qtimer Signal Slot Game
• Qtimer Signal Slot Games
• Qtimer Signal Slot Car
• Qt Qtimer Signal Slot

8BiTs 매일 코딩 홈페이지. In this paper, a QTimer is defined, and the slot function onTimeOut is defined as the slot function corresponding to the timeout signal. The code in the constructor of the window class is as follows.

The QTimer class provides repetitive and single-shot timers. More...

As the documentation for QTimer states, when discussing the called slot: It should be written in such a way that it always returns quickly (typically after processing one data item) so that Qt can deliver events to the user interface and stop the timer as soon as it has done all its work. C (Cpp) QTimer::connect - 30 examples found. These are the top rated real world C (Cpp) examples of QTimer::connect extracted from open source projects. You can rate examples to help us improve the quality of examples. Next, its timeout signal is connected to the slot that will do the work, it is started with a value of 1000 milliseconds, indicating that it will time out every second. QTimer also provides a static function for single-shot timers. For example: QTimer:: singleShot(200, this, SLOT(updateCaption)).

Properties

• 1 property inherited from QObject

Public Functions

• 31 public functions inherited from QObject

Public Slots

• 1 public slot inherited from QObject

Signals

• 2 signals inherited from QObject

Static Public Members

• 11 static public members inherited from QObject

Reimplemented Protected Functions

• 9 protected functions inherited from QObject

Detailed Description

The QTimer class provides repetitive and single-shot timers.

The QTimer class provides a high-level programming interface for timers. To use it, create a QTimer, connect its timeout() signal to the appropriate slots, and call start(). From then on, it will emit the timeout() signal at constant intervals.

Example for a one second (1000 millisecond) timer (from the Analog Clock example):

From then on, the update() slot is called every second.

You can set a timer to time out only once by calling setSingleShot(true). You can also use the static QTimer::singleShot() function to call a slot after a specified interval:

In multithreaded applications, you can use QTimer in any thread that has an event loop. To start an event loop from a non-GUI thread, use QThread::exec(). Qt uses the timer's thread affinity to determine which thread will emit the timeout() signal. Because of this, you must start and stop the timer in its thread; it is not possible to start a timer from another thread.

As a special case, a QTimer with a timeout of 0 will time out as soon as all the events in the window system's event queue have been processed. This can be used to do heavy work while providing a snappy user interface:

From then on, processOneThing() will be called repeatedly. It should be written in such a way that it always returns quickly (typically after processing one data item) so that Qt can deliver events to the user interface and stop the timer as soon as it has done all its work. This is the traditional way of implementing heavy work in GUI applications, but as multithreading is nowadays becoming available on more and more platforms, we expect that zero-millisecond QTimer objects will gradually be replaced by QThreads.

Accuracy and Timer Resolution

The accuracy of timers depends on the underlying operating system and hardware. Most platforms support a resolution of 1 millisecond, though the accuracy of the timer will not equal this resolution in many real-world situations.

The accuracy also depends on the timer type. For Qt::PreciseTimer, QTimer will try to keep the accurance at 1 millisecond. Precise timers will also never time out earlier than expected.

For Qt::CoarseTimer and Qt::VeryCoarseTimer types, QTimer may wake up earlier than expected, within the margins for those types: 5% of the interval for Qt::CoarseTimer and 500 ms for Qt::VeryCoarseTimer.

All timer types may time out later than expected if the system is busy or unable to provide the requested accuracy. In such a case of timeout overrun, Qt will emit activated() only once, even if multiple timeouts have expired, and then will resume the original interval.

Alternatives to QTimer

An alternative to using QTimer is to call QObject::startTimer() for your object and reimplement the QObject::timerEvent() event handler in your class (which must inherit QObject). The disadvantage is that timerEvent() does not support such high-level features as single-shot timers or signals.

Another alternative is QBasicTimer. It is typically less cumbersome than using QObject::startTimer() directly. See Timers for an overview of all three approaches.

Some operating systems limit the number of timers that may be used; Qt tries to work around these limitations.

See also QBasicTimer, QTimerEvent, QObject::timerEvent(), Timers, Analog Clock Example, and Wiggly Example.

Property Documentation

active : const bool

This boolean property is true if the timer is running; otherwise false.

This property was introduced in Qt 4.3.

Access functions:

interval : int

This property holds the timeout interval in milliseconds.

The default value for this property is 0. A QTimer with a timeout interval of 0 will time out as soon as all the events in the window system's event queue have been processed.

Setting the interval of an active timer changes its timerId().

Access functions:

See also singleShot.

remainingTime : const int

This property holds the remaining time in milliseconds.

Returns the timer's remaining value in milliseconds left until the timeout. If the timer is inactive, the returned value will be -1. If the timer is overdue, the returned value will be 0.

This property was introduced in Qt 5.0.

Access functions:

See also interval.

singleShot : bool

This property holds whether the timer is a single-shot timer.

A single-shot timer fires only once, non-single-shot timers fire every interval milliseconds.

Access functions:

See also interval and singleShot().

timerType : Qt::TimerType

This property holds controls the accuracy of the timer.

The default value for this property is Qt::CoarseTimer.

Access functions:

See also Qt::TimerType.

Member Function Documentation

QTimer::QTimer(QObject * parent = 0)

Constructs a timer with the given parent.

QTimer::~QTimer()

Destroys the timer.

bool QTimer::isActive() const

Returns true if the timer is running (pending); otherwise returns false.

Note: Getter function for property active.

[static] void QTimer::singleShot(int msec, const QObject * receiver, const char * member)

This static function calls a slot after a given time interval.

It is very convenient to use this function because you do not need to bother with a timerEvent or create a local QTimer object.

Example:

This sample program automatically terminates after 10 minutes (600,000 milliseconds).

The receiver is the receiving object and the member is the slot. The time interval is msec milliseconds.

Note: This function is reentrant.

See also setSingleShot() and start().

[static] void QTimer::singleShot(int msec, Qt::TimerType timerType, const QObject * receiver, const char * member)

This is an overloaded function.

This static function calls a slot after a given time interval.

It is very convenient to use this function because you do not need to bother with a timerEvent or create a local QTimer object.

The receiver is the receiving object and the member is the slot. The time interval is msec milliseconds. The timerType affects the accuracy of the timer.

Note: This function is reentrant.

See also start().

[static] void QTimer::singleShot(int msec, const QObject * receiver, PointerToMemberFunction method)

This is an overloaded function.

This static function calls a member function of a QObject after a given time interval.

It is very convenient to use this function because you do not need to bother with a timerEvent or create a local QTimer object.

The receiver is the receiving object and the method is the member function. The time interval is msec milliseconds.

If receiver is destroyed before the interval occurs, the method will not be called. The function will be run in the thread of receiver. The receiver's thread must have a running Qt event loop.

Note: This function is reentrant.

This function was introduced in Qt 5.4.

See also start().

[static] void QTimer::singleShot(int msec, Qt::TimerType timerType, const QObject * receiver, PointerToMemberFunction method)

This is an overloaded function.

This static function calls a member function of a QObject after a given time interval.

It is very convenient to use this function because you do not need to bother with a timerEvent or create a local QTimer object.

The receiver is the receiving object and the method is the member function. The time interval is msec milliseconds. The timerType affects the accuracy of the timer.

If receiver is destroyed before the interval occurs, the method will not be called. The function will be run in the thread of receiver. The receiver's thread must have a running Qt event loop.

Note: This function is reentrant.

This function was introduced in Qt 5.4.

See also start().

[static] void QTimer::singleShot(int msec, Functor functor)

This is an overloaded function.

This static function calls functor after a given time interval.

It is very convenient to use this function because you do not need to bother with a timerEvent or create a local QTimer object.

The time interval is msec milliseconds.

Note: This function is reentrant.

This function was introduced in Qt 5.4.

See also start().

[static] void QTimer::singleShot(int msec, Qt::TimerType timerType, Functor functor)

This is an overloaded function.

This static function calls functor after a given time interval.

It is very convenient to use this function because you do not need to bother with a timerEvent or create a local QTimer object.

The time interval is msec milliseconds. The timerType affects the accuracy of the timer.

Note: This function is reentrant.

This function was introduced in Qt 5.4.

See also start().

[static] void QTimer::singleShot(int msec, const QObject * context, Functor functor)

This is an overloaded function.

This static function calls functor after a given time interval.

It is very convenient to use this function because you do not need to bother with a timerEvent or create a local QTimer object.

The time interval is msec milliseconds.

If context is destroyed before the interval occurs, the method will not be called. The function will be run in the thread of context. The context's thread must have a running Qt event loop.

Note: This function is reentrant.

This function was introduced in Qt 5.4.

See also start().

[static] void QTimer::singleShot(int msec, Qt::TimerType timerType, const QObject * context, Functor functor)

This is an overloaded function.

This static function calls functor after a given time interval.

It is very convenient to use this function because you do not need to bother with a timerEvent or create a local QTimer object.

The time interval is msec milliseconds. The timerType affects the accuracy of the timer.

If context is destroyed before the interval occurs, the method will not be called. The function will be run in the thread of context. The context's thread must have a running Qt event loop.

Note: This function is reentrant.

This function was introduced in Qt 5.4.

See also start().

[slot] void QTimer::start(int msec)

Starts or restarts the timer with a timeout interval of msec milliseconds.

If the timer is already running, it will be stopped and restarted.

If singleShot is true, the timer will be activated only once.

[slot] void QTimer::start()

This function overloads start().

Starts or restarts the timer with the timeout specified in interval.

If the timer is already running, it will be stopped and restarted.

If singleShot is true, the timer will be activated only once.

[slot] void QTimer::stop()

Stops the timer.

See also start().

[signal] void QTimer::timeout()

This signal is emitted when the timer times out.

Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.

See also interval, start(), and stop().

[virtual protected] void QTimer::timerEvent(QTimerEvent * e)

Reimplemented from QObject::timerEvent().

int QTimer::timerId() const

Returns the ID of the timer if the timer is running; otherwise returns -1.

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.

Synopsis¶

Functions¶

• def interval ()
• def isActive ()
• def isSingleShot ()
• def setInterval (msec)
• def setSingleShot (singleShot)
• def timerId ()

Signals¶

• def timeout ()

Static functions¶

• def singleShot (arg__1, arg__2)
• def singleShot (msec, receiver, member)

Detailed Description¶

The PySide.QtCore.QTimer class provides repetitive and single-shot timers.

The PySide.QtCore.QTimer class provides a high-level programming interface for timers. To use it, create a PySide.QtCore.QTimer , connect its PySide.QtCore.QTimer.timeout() signal to the appropriate slots, and call PySide.QtCore.QTimer.start() . From then on it will emit the PySide.QtCore.QTimer.timeout() signal at constant intervals.

Example for a one second (1000 millisecond) timer (from the Analog Clock example):

From then on, the update() slot is called every second.

You can set a timer to time out only once by calling setSingleShot(true). You can also use the static QTimer.singleShot() function to call a slot after a specified interval:

In multithreaded applications, you can use PySide.QtCore.QTimer in any thread that has an event loop. To start an event loop from a non-GUI thread, use QThread.exec() . Qt uses the timer’s threadaffinity to determine which thread will emit the PySide.QtCore.QTimer.timeout() signal. Because of this, you must start and stop the timer in its thread; it is not possible to start a timer from another thread.

As a special case, a PySide.QtCore.QTimer with a timeout of 0 will time out as soon as all the events in the window system’s event queue have been processed. This can be used to do heavy work while providing a snappy user interface:

processOneThing() will from then on be called repeatedly. It should be written in such a way that it always returns quickly (typically after processing one data item) so that Qt can deliver events to widgets and stop the timer as soon as it has done all its work. This is the traditional way of implementing heavy work in GUI applications; multithreading is now becoming available on more and more platforms, and we expect that zero-millisecond QTimers will gradually be replaced by PySide.QtCore.QThread s.

Accuracy and Timer Resolution¶

Timers will never time out earlier than the specified timeout value and they are not guaranteed to time out at the exact value specified. In many situations, they may time out late by a period of time that depends on the accuracy of the system timers.

The accuracy of timers depends on the underlying operating system and hardware. Most platforms support a resolution of 1 millisecond, though the accuracy of the timer will not equal this resolution in many real-world situations.

If Qt is unable to deliver the requested number of timer clicks, it will silently discard some.

Alternatives to QTimer¶

An alternative to using PySide.QtCore.QTimer is to call QObject.startTimer() for your object and reimplement the QObject.timerEvent() event handler in your class (which must inherit PySide.QtCore.QObject ). The disadvantage is that PySide.QtCore.QTimer.timerEvent() does not support such high-level features as single-shot timers or signals.

Another alternative to using PySide.QtCore.QTimer is to use PySide.QtCore.QBasicTimer . It is typically less cumbersome than using QObject.startTimer() directly. See Timers for an overview of all three approaches.

Some operating systems limit the number of timers that may be used; Qt tries to work around these limitations.

See also

PySide.QtCore.QBasicTimerPySide.QtCore.QTimerEventQObject.timerEvent()TimersAnalog Clock ExampleWiggly Example

Constructs a timer with the given parent .

This property holds the timeout interval in milliseconds.

The default value for this property is 0. A PySide.QtCore.QTimer with a timeout interval of 0 will time out as soon as all the events in the window system’s event queue have been processed.

Setting the interval of an active timer changes its PySide.QtCore.QTimer.timerId() .

This boolean property is true if the timer is running; otherwise false.

This property holds whether the timer is a single-shot timer.

A single-shot timer fires only once, non-single-shot timers fire every PySide.QtCore.QTimer.interval() milliseconds.

See also

Qtimer Signal Slot Game

This property holds the timeout interval in milliseconds.

The default value for this property is 0. A PySide.QtCore.QTimer with a timeout interval of 0 will time out as soon as all the events in the window system’s event queue have been processed.

Setting the interval of an active timer changes its PySide.QtCore.QTimer.timerId() .

This property holds whether the timer is a single-shot timer.

A single-shot timer fires only once, non-single-shot timers fire every PySide.QtCore.QTimer.interval() milliseconds.

See also

This static function calls a slot after a given time interval.

It is very convenient to use this function because you do not need to bother with a PySide.QtCore.QObject.timerEvent() or create a local PySide.QtCore.QTimer object.

Example:

This sample program automatically terminates after 10 minutes (600,000 milliseconds).

Qtimer Signal Slot Games

The receiver is the receiving object and the member is the slot. The time interval is msec milliseconds.

See also

This function overloads PySide.QtCore.QTimer.start() .

Qtimer Signal Slot Car

Starts or restarts the timer with the timeout specified in PySide.QtCore.QTimer.interval() .

Qt Qtimer Signal Slot

If PySide.QtCore.QTimer.singleShot() is true, the timer will be activated only once.

Starts or restarts the timer with a timeout interval of msec milliseconds.

Stops the timer.

PySide.QtCore.QTimer.timeout()¶

Returns the ID of the timer if the timer is running; otherwise returns -1.