Contents

• Public Types
• Properties
• Public Functions
• Public Slots
• Signals
• Protected Functions
• Reimplemented Protected Functions
• Detailed Description

Detailed Description

TheQAbstractAnimation class is the base of all animations.

The class defines the functions for the functionality shared by all animations. By inheriting this class, you can create custom animations that plug into the rest of the animation framework.

The progress of an animation is given by its current time (currentLoopTime()), which is measured in milliseconds from the start of the animation (0) to its end (duration()). The value is updated automatically while the animation is running. It can also be set directly withsetCurrentTime().

At any point an animation is in one of three states:Running,Stopped, orPaused--as defined by theState enum. The current state can be changed by callingstart(),stop(),pause(), orresume(). An animation will always reset itscurrent time when it is started. If paused, it will continue with the same current time when resumed. When an animation is stopped, it cannot be resumed, but will keep its current time (until started again).QAbstractAnimation will emitstateChanged() whenever its state changes.

An animation can loop any number of times by setting theloopCount property. When an animation's current time reaches itsduration(), it will reset the current time and keep running. A loop count of 1 (the default value) means that the animation will run one time. Note that a duration of -1 means that the animation will run until stopped; the current time will increase indefinitely. When the current time equalsduration() and the animation is in its final loop, theStopped state is entered, and thefinished() signal is emitted.

QAbstractAnimation provides pure virtual functions used by subclasses to track the progress of the animation:duration() andupdateCurrentTime(). Theduration() function lets you report a duration for the animation (as discussed above). The animation framework callsupdateCurrentTime() when current time has changed. By reimplementing this function, you can track the animation progress. Note that neither the interval between calls nor the number of calls to this function are defined; though, it will normally be 60 updates per second.

By reimplementingupdateState(), you can track the animation's state changes, which is particularly useful for animations that are not driven by time.

Member Type Documentation

enum QAbstractAnimation::DeletionPolicy

enum QAbstractAnimation::Direction

This enum describes the direction of the animation when inRunning state.

See alsodirection.

enum QAbstractAnimation::State

This enum describes the state of the animation.

See alsostate() andstateChanged().

Property Documentation

currentLoop : constint

This property holds the current loop of the animation.

This property describes the current loop of the animation. By default, the animation's loop count is 1, and so the current loop will always be 0. If the loop count is 2 and the animation runs past its duration, it will automatically rewind and restart at current time 0, and current loop 1, and so on.

When the current loop changes,QAbstractAnimation emits the currentLoopChanged() signal.

Access functions:

Notifier signal:

currentTime :int

This property holds the current time and progress of the animation.

This property describes the animation's current time. You can change the current time by calling setCurrentTime, or you can callstart() and let the animation run, setting the current time automatically as the animation progresses.

The animation's current time starts at 0, and ends attotalDuration().

Access functions:

See alsoloopCount andcurrentLoopTime().

direction :Direction

This property holds the direction of the animation when it is in Running state.

This direction indicates whether the time moves from 0 towards the animation duration, or from the value of the duration and towards 0 afterstart() has been called.

By default, this property is set toForward.

Access functions:

Notifier signal:

duration : constint

This property holds the duration of the animation.

If the duration is -1, it means that the duration is undefined. In this case,loopCount is ignored.

Access functions:

loopCount :int

This property holds the loop count of the animation.

This property describes the loop count of the animation as an integer. By default this value is 1, indicating that the animation should run once only, and then stop. By changing it you can let the animation loop several times. With a value of 0, the animation will not run at all, and with a value of -1, the animation will loop forever until stopped. It is not supported to have loop on an animation that has an undefined duration. It will only run once.

Access functions:

state : constState

This property holds state of the animation.

This property describes the current state of the animation. When the animation state changes,QAbstractAnimation emits the stateChanged() signal.

Access functions:

Notifier signal:

Member Function Documentation

QAbstractAnimation::QAbstractAnimation(QObject * parent = 0)

Constructs theQAbstractAnimation base class, and passesparent toQObject's constructor.

See alsoQVariantAnimation andQAnimationGroup.

[virtual]QAbstractAnimation::~QAbstractAnimation()

Stops the animation if it's running, then destroys theQAbstractAnimation. If the animation is part of aQAnimationGroup, it is automatically removed before it's destroyed.

int QAbstractAnimation::currentLoopTime() const

Returns the current time inside the current loop. It can go from 0 toduration().

See alsoduration() andcurrentTime.

[virtual protected]bool QAbstractAnimation::event(QEvent * event)

Reimplemented fromQObject::event().

[signal]void QAbstractAnimation::finished()

QAbstractAnimation emits this signal after the animation has stopped and has reached the end.

This signal is emitted afterstateChanged().

See alsostateChanged().

QAnimationGroup * QAbstractAnimation::group() const

If this animation is part of aQAnimationGroup, this function returns a pointer to the group; otherwise, it returns 0.

See alsoQAnimationGroup::addAnimation().

[slot]void QAbstractAnimation::pause()

Pauses the animation. When the animation is paused,state() returns Paused. The value ofcurrentTime will remain unchanged untilresume() orstart() is called. If you want to continue from the current time, callresume().

See alsostart(),state(), andresume().

[slot]void QAbstractAnimation::resume()

Resumes the animation after it was paused. When the animation is resumed, it emits the resumed() andstateChanged() signals. The currenttime is not changed.

See alsostart(),pause(), andstate().

[slot]void QAbstractAnimation::setPaused(bool paused)

Ifpaused is true, the animation is paused. Ifpaused is false, the animation is resumed.

See alsostate(),pause(), andresume().

[slot]void QAbstractAnimation::start(QAbstractAnimation::DeletionPolicy policy = KeepWhenStopped)

Starts the animation. Thepolicy argument says whether or not the animation should be deleted when it's done. When the animation starts, thestateChanged() signal is emitted, andstate() returns Running. When control reaches the event loop, the animation will run by itself, periodically callingupdateCurrentTime() as the animation progresses.

If the animation is currently stopped or has already reached the end, calling start() will rewind the animation and start again from the beginning. When the animation reaches the end, the animation will either stop, or if the loop level is more than 1, it will rewind and continue from the beginning.

If the animation is already running, this function does nothing.

See alsostop() andstate().

[slot]void QAbstractAnimation::stop()

Stops the animation. When the animation is stopped, it emits thestateChanged() signal, andstate() returns Stopped. The current time is not changed.

If the animation stops by itself after reaching the end (i.e.,currentLoopTime() ==duration() andcurrentLoop() >loopCount() - 1), thefinished() signal is emitted.

See alsostart() andstate().

int QAbstractAnimation::totalDuration() const

Returns the total and effective duration of the animation, including the loop count.

See alsoduration() andcurrentTime.

[pure virtual protected]void QAbstractAnimation::updateCurrentTime(int currentTime)

This pure virtual function is called every time the animation'scurrentTime changes.

See alsoupdateState().

[virtual protected]void QAbstractAnimation::updateDirection(QAbstractAnimation::Direction direction)

This virtual function is called byQAbstractAnimation when the direction of the animation is changed. Thedirection argument is the new direction.

See alsosetDirection() anddirection().

[virtual protected]void QAbstractAnimation::updateState(QAbstractAnimation::State newState,QAbstractAnimation::State oldState)

This virtual function is called byQAbstractAnimation when the state of the animation is changed fromoldState tonewState.

See alsostart(),stop(),pause(), andresume().