path: root/src/declarative/util/qmltimer.cpp

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#include "qmltimer_p.h"

#include <QtCore/qcoreapplication.h>
#include <QtCore/qpauseanimation.h>
#include <qdebug.h>

#include <private/qobject_p.h>

QT_BEGIN_NAMESPACE



class QmlTimerPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QmlTimer)
public:
    QmlTimerPrivate()
        : interval(1000), running(false), repeating(false), triggeredOnStart(false)
        , classBegun(false), componentComplete(false), firstTick(true) {}
    int interval;
    QPauseAnimation pause;
    bool running : 1;
    bool repeating : 1;
    bool triggeredOnStart : 1;
    bool classBegun : 1;
    bool componentComplete : 1;
    bool firstTick : 1;
};

/*!
    \qmlclass Timer QmlTimer
    \brief The Timer item triggers a handler at a specified interval.

    A timer can be used to trigger an action either once, or repeatedly
    at a given interval.

    Here is a timer that shows the current date and time, and updates
    the text every 500 milliseconds:

    \qml
    Timer {
        interval: 500; running: true; repeat: true
        onTriggered: time.text = Date().toString()
    }
    Text {
        id: time
    }
    \endqml

    QmlTimer is synchronized with the animation timer.  Since the animation
    timer is usually set to 60fps, the resolution of QmlTimer will be
    at best 16ms.

    If the Timer is running and one of its properties is changed, the
    elapsed time will be reset.  For example, if a Timer with interval of
    1000ms has its \e repeat property changed 500ms after starting, the
    elapsed time will be reset to 0, and the Timer will be triggered
    1000ms later.
*/

QmlTimer::QmlTimer(QObject *parent)
    : QObject(*(new QmlTimerPrivate), parent)
{
    Q_D(QmlTimer);
    connect(&d->pause, SIGNAL(currentLoopChanged(int)), this, SLOT(ticked()));
    connect(&d->pause, SIGNAL(finished()), this, SLOT(finished()));
    d->pause.setLoopCount(1);
    d->pause.setDuration(d->interval);
}

/*!
    \qmlproperty int Timer::interval

    Sets the \a interval between triggers, in milliseconds.

    The default interval is 1000 milliseconds.
*/
void QmlTimer::setInterval(int interval)
{
    Q_D(QmlTimer);
    if (interval != d->interval) {
        d->interval = interval;
        update();
    }
}

int QmlTimer::interval() const
{
    Q_D(const QmlTimer);
    return d->interval;
}

/*!
    \qmlproperty bool Timer::running

    If set to true, starts the timer; otherwise stops the timer.
    For a non-repeating timer, \a running is set to false after the
    timer has been triggered.

    \a running defaults to false.

    \sa repeat
*/
bool QmlTimer::isRunning() const
{
    Q_D(const QmlTimer);
    return d->running;
}

void QmlTimer::setRunning(bool running)
{
    Q_D(QmlTimer);
    if (d->running != running) {
        d->running = running;
        d->firstTick = true;
        emit runningChanged();
        update();
    }
}

/*!
    \qmlproperty bool Timer::repeat

    If \a repeat is true the timer is triggered repeatedly at the
    specified interval; otherwise, the timer will trigger once at the
    specified interval and then stop (i.e. running will be set to false).

    \a repeat defaults to false.

    \sa running
*/
bool QmlTimer::isRepeating() const
{
    Q_D(const QmlTimer);
    return d->repeating;
}

void QmlTimer::setRepeating(bool repeating)
{
    Q_D(QmlTimer);
    if (repeating != d->repeating) {
        d->repeating = repeating;
        update();
    }
}

/*!
    \qmlproperty bool Timer::triggeredOnStart

    When a timer is started, the first trigger is usually after the specified
    interval has elapsed.  It is sometimes desirable to trigger immediately
    when the timer is started; for example, to establish an initial
    state.

    If \a triggeredOnStart is true, the timer is triggered immediately
    when started, and subsequently at the specified interval. Note that if
    \e repeat is set to false, the timer is triggered twice; once on start,
    and again at the interval.

    \a triggeredOnStart defaults to false.

    \sa running
*/
bool QmlTimer::triggeredOnStart() const
{
    Q_D(const QmlTimer);
    return d->triggeredOnStart;
}

void QmlTimer::setTriggeredOnStart(bool triggeredOnStart)
{
    Q_D(QmlTimer);
    if (d->triggeredOnStart != triggeredOnStart) {
        d->triggeredOnStart = triggeredOnStart;
        update();
    }
}

/*!
    \qmlmethod Timer::start()
    \brief Starts the timer.

    If the timer is already running, calling this method has no effect.  The
    \c running property will be true following a call to \c start().
*/
void QmlTimer::start()
{
    setRunning(true);
}

/*!
    \qmlmethod Timer::stop()
    \brief Stops the timer.

    If the timer is not running, calling this method has no effect.  The
    \c running property will be false following a call to \c stop().
*/
void QmlTimer::stop()
{
    setRunning(false);
}

/*!
    \qmlmethod Timer::restart()
    \brief Restarts the timer.

    If the Timer is not running it will be started, otherwise it will be
    stopped, reset to initial state and started.  The \c running property
    will be true following a call to \c restart().
*/
void QmlTimer::restart()
{
    setRunning(false);
    setRunning(true);
}

void QmlTimer::update()
{
    Q_D(QmlTimer);
    if (d->classBegun && !d->componentComplete)
        return;
    d->pause.stop();
    if (d->running) {
        d->pause.setCurrentTime(0);
        d->pause.setLoopCount(d->repeating ? -1 : 1);
        d->pause.setDuration(d->interval);
        d->pause.start();
        if (d->triggeredOnStart && d->firstTick) {
            QCoreApplication::removePostedEvents(this, QEvent::MetaCall);
            QMetaObject::invokeMethod(this, "ticked", Qt::QueuedConnection);
        }
    }
}

void QmlTimer::classBegin()
{
    Q_D(QmlTimer);
    d->classBegun = true;
}

void QmlTimer::componentComplete()
{
    Q_D(QmlTimer);
    d->componentComplete = true;
    update();
}

/*!
    \qmlsignal Timer::onTriggered()

    This handler is called when the Timer is triggered.
*/
void QmlTimer::ticked()
{
    Q_D(QmlTimer);
    if (d->running && (d->pause.currentTime() > 0 || (d->triggeredOnStart && d->firstTick)))
        emit triggered();
    d->firstTick = false;
}

void QmlTimer::finished()
{
    Q_D(QmlTimer);
    if (d->repeating || !d->running)
        return;
    emit triggered();
    d->running = false;
    d->firstTick = false;
    emit runningChanged();
}

QT_END_NAMESPACE