内容

• 公共类型
• 特性
• 公共函数
• 公共槽
• 信号
• 重实现保护函数
• 详细描述

QTimeLine Class

QTimeLine class provides a timeline for controlling animations. 更多...

头：	#include <QTimeLine>
qmake:	QT += core
Since:	Qt 4.2
继承：	QObject

• 所有成员列表，包括继承成员

公共类型

enum	CurveShape { EaseInCurve, EaseOutCurve, EaseInOutCurve, LinearCurve, SineCurve, CosineCurve }
enum	Direction { Forward, Backward }
enum	State { NotRunning, Paused, Running }

特性

currentTime : int curveShape : CurveShape direction : Direction duration : int

easingCurve : QEasingCurve loopCount : int updateInterval : int

• 1 特性继承自 QObject

公共函数

	QTimeLine (int duration = 1000, QObject * parent = Q_NULLPTR)
virtual	~QTimeLine ()
int	currentFrame () const
int	currentTime () const
qreal	currentValue () const
CurveShape	curveShape () const
Direction	direction () const
int	duration () const
QEasingCurve	easingCurve () const
int	endFrame () const
int	frameForTime (int msec ) const
int	loopCount () const
void	setCurveShape (CurveShape shape )
void	setDirection (Direction direction )
void	setDuration (int duration )
void	setEasingCurve (const QEasingCurve & curve )
void	setEndFrame (int frame )
void	setFrameRange (int startFrame , int endFrame )
void	setLoopCount (int count )
void	setStartFrame (int frame )
void	setUpdateInterval (int interval )
int	startFrame () const
State	state () const
int	updateInterval () const
virtual qreal	valueForTime (int msec ) const

• 32 公共函数继承自 QObject

公共槽

void	resume ()
void	setCurrentTime (int msec )
void	setPaused (bool paused )
void	start ()
void	stop ()
void	toggleDirection ()

• 1 公共槽继承自 QObject

信号

void	finished ()
void	frameChanged (int frame )
void	stateChanged (QTimeLine::State newState )
void	valueChanged (qreal value )

• 2 信号继承自 QObject

重实现保护函数

virtual void

timerEvent (QTimerEvent * event )

• 9 保护函数继承自 QObject

额外继承成员

• 11 静态公共成员继承自 QObject
• 9 保护函数继承自 QObject

详细描述

QTimeLine class provides a timeline for controlling animations.

It's most commonly used to animate a GUI control by calling a slot periodically. You can construct a timeline by passing its duration in milliseconds to QTimeLine 's constructor. The timeline's duration describes for how long the animation will run. Then you set a suitable frame range by calling setFrameRange (). Finally connect the frameChanged () signal to a suitable slot in the widget you wish to animate (for example, setValue() in QProgressBar ). When you proceed to calling start (), QTimeLine will enter Running state, and start emitting frameChanged () at regular intervals, causing your widget's connected property's value to grow from the lower end to the upper and of your frame range, at a steady rate. You can specify the update interval by calling setUpdateInterval (). When done, QTimeLine 进入 NotRunning state, and emits finished ().

范例：

...
progressBar = new QProgressBar(this);
progressBar->setRange(0, 100);
// Construct a 1-second timeline with a frame range of 0 - 100
QTimeLine *timeLine = new QTimeLine(1000, this);
timeLine->setFrameRange(0, 100);
connect(timeLine, SIGNAL(frameChanged(int)), progressBar, SLOT(setValue(int)));
// Clicking the push button will start the progress bar animation
pushButton = new QPushButton(tr("Start animation"), this);
connect(pushButton, SIGNAL(clicked()), timeLine, SLOT(start()));
...
					

By default the timeline runs once, from the beginning and towards the end, upon which you must call start () again to restart from the beginning. To make the timeline loop, you can call setLoopCount (), passing the number of times the timeline should run before finishing. The direction can also be changed, causing the timeline to run backward, by calling setDirection (). You can also pause and unpause the timeline while it's running by calling setPaused (). For interactive control, the setCurrentTime () function is provided, which sets the time position of the time line directly. Although most useful in NotRunning state, (e.g., connected to a valueChanged () signal in a QSlider ,) this function can be called at any time.

The frame interface is useful for standard widgets, but QTimeLine can be used to control any type of animation. The heart of QTimeLine lies in the valueForTime () function, which generates a value between 0 and 1 for a given time. This value is typically used to describe the steps of an animation, where 0 is the first step of an animation, and 1 is the last step. When running, QTimeLine generates values between 0 and 1 by calling valueForTime () and emitting valueChanged ()。默认情况下， valueForTime () applies an interpolation algorithm to generate these value. You can choose from a set of predefined timeline algorithms by calling setCurveShape ().

Note that by default, QTimeLine uses the EaseInOut curve shape, which provides a value that grows slowly, then grows steadily, and finally grows slowly. For a custom timeline, you can reimplement valueForTime (), in which case QTimeLine 's curveShape property is ignored.

另请参阅 QProgressBar and QProgressDialog .

成员类型文档编制

enum QTimeLine:: CurveShape

This enum describes the default shape of QTimeLine 's value curve. The default, shape is EaseInOutCurve. The curve defines the relation between the value and the timeline.

常量	值	描述
QTimeLine::EaseInCurve	0	The value starts growing slowly, then increases in speed.
QTimeLine::EaseOutCurve	1	The value starts growing steadily, then ends slowly.
QTimeLine::EaseInOutCurve	2	The value starts growing slowly, then runs steadily, then grows slowly again.
QTimeLine::LinearCurve	3	The value grows linearly (e.g., if the duration is 1000 ms, the value at time 500 ms is 0.5).
QTimeLine::SineCurve	4	The value grows sinusoidally.
QTimeLine::CosineCurve	5	The value grows cosinusoidally.

另请参阅 setCurveShape ().

enum QTimeLine:: Direction

This enum describes the direction of the timeline when in 运行 状态。

常量	值	描述
QTimeLine::Forward	0	The current time of the timeline increases with time (i.e., moves from 0 and towards the end / duration).
QTimeLine::Backward	1	The current time of the timeline decreases with time (i.e., moves from the end / duration and towards 0).

另请参阅 setDirection ().

enum QTimeLine:: State

This enum describes the state of the timeline.

常量	值	描述
QTimeLine::NotRunning	0	The timeline is not running. This is the initial state of QTimeLine , and the state QTimeLine reenters when finished. The current time, frame and value remain unchanged until either setCurrentTime () is called, or the timeline is started by calling start ().
QTimeLine::Paused	1	The timeline is paused (i.e., temporarily suspended). Calling setPaused (false) will resume timeline activity.
QTimeLine::Running	2	The timeline is running. While control is in the event loop, QTimeLine will update its current time at regular intervals, emitting valueChanged () 和 frameChanged () when appropriate.

另请参阅 state () 和 stateChanged ().

特性文档编制

currentTime : int

This property holds the current time of the time line.

当 QTimeLine is in Running state, this value is updated continuously as a function of the duration and direction of the timeline. Otherwise, it is value that was current when stop () was called last, or the value set by setCurrentTime().

默认情况下，此特性包含 0 值。

访问函数：

int	currentTime () const
void	setCurrentTime (int msec )

curveShape : CurveShape

This property holds the shape of the timeline curve.

The curve shape describes the relation between the time and value for the base implementation of valueForTime ().

If you have reimplemented valueForTime (), this value is ignored.

默认情况下，此特性被设为 EaseInOutCurve .

访问函数：

CurveShape	curveShape () const
void	setCurveShape (CurveShape shape )

另请参阅 valueForTime ().

direction : Direction

This property holds the direction of the timeline when QTimeLine 是在 运行 状态。

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

默认情况下，此特性被设为 Forward .

访问函数：

Direction	direction () const
void	setDirection (Direction direction )

duration : int

This property holds the total duration of the timeline in milliseconds.

By default, this value is 1000 (i.e., 1 second), but you can change this by either passing a duration to QTimeLine 's constructor, or by calling setDuration(). The duration must be larger than 0.

注意： Changing the duration does not cause the current time to be reset to zero or the new duration. You also need to call setCurrentTime () with the desired value.

访问函数：

int	duration () const
void	setDuration (int duration )

easingCurve : QEasingCurve

Specifies the easing curve that the timeline will use. If both easing curve and curveShape are set, the last set property will override the previous one. (If valueForTime () is reimplemented it will override both)

该特性在 Qt 4.6 引入。

访问函数：

QEasingCurve	easingCurve () const
void	setEasingCurve (const QEasingCurve & curve )

loopCount : int

This property holds the number of times the timeline should loop before it's finished.

A loop count of of 0 means that the timeline will loop forever.

By default, this property contains a value of 1.

访问函数：

int	loopCount () const
void	setLoopCount (int count )

updateInterval : int

This property holds the time in milliseconds between each time QTimeLine updates its current time.

When updating the current time, QTimeLine 将发射 valueChanged () if the current value changed, and frameChanged () if the frame changed.

By default, the interval is 40 ms, which corresponds to a rate of 25 updates per second.

访问函数：

int	updateInterval () const
void	setUpdateInterval (int interval )

成员函数文档编制

QTimeLine:: QTimeLine ( int duration = 1000, QObject * parent = Q_NULLPTR)

Constructs a timeline with a duration of duration 毫秒。 parent 会被传递给 QObject 's constructor. The default duration is 1000 milliseconds.

[virtual] QTimeLine:: ~QTimeLine ()

Destroys the timeline.

int QTimeLine:: currentFrame () const

Returns the frame corresponding to the current time.

另请参阅 currentTime (), frameForTime ()，和 setFrameRange ().

qreal QTimeLine:: currentValue () const

Returns the value corresponding to the current time.

另请参阅 valueForTime () 和 currentFrame ().

int QTimeLine:: endFrame () const

Returns the end frame, which is the frame corresponding to the end of the timeline (i.e., the frame for which the current value is 1).

另请参阅 setEndFrame () 和 setFrameRange ().

[signal] void QTimeLine:: finished ()

此信号被发射当 QTimeLine finishes (i.e., reaches the end of its time line), and does not loop.

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

[signal] void QTimeLine:: frameChanged ( int frame )

QTimeLine emits this signal at regular intervals when in 运行 state, but only if the current frame changes. frame is the current frame number.

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

另请参阅 QTimeLine::setFrameRange () 和 QTimeLine::updateInterval .

int QTimeLine:: frameForTime ( int msec ) const

Returns the frame corresponding to the time msec . This value is calculated using a linear interpolation of the start and end frame, based on the value returned by valueForTime ().

另请参阅 valueForTime () 和 setFrameRange ().

[slot] void QTimeLine:: resume ()

Resumes the timeline from the current time. QTimeLine will reenter Running state, and once it enters the event loop, it will update its current time, frame and value at regular intervals.

In contrast to start (), this function does not restart the timeline before it resumes.

另请参阅 start (), updateInterval (), frameChanged ()，和 valueChanged ().

void QTimeLine:: setEndFrame ( int frame )

Sets the end frame, which is the frame corresponding to the end of the timeline (i.e., the frame for which the current value is 1), to frame .

另请参阅 endFrame (), startFrame ()，和 setFrameRange ().

void QTimeLine:: setFrameRange ( int startFrame , int endFrame )

Sets the timeline's frame counter to start at startFrame , and end and endFrame . For each time value, QTimeLine will find the corresponding frame when you call currentFrame () 或 frameForTime () by interpolating, using the return value of valueForTime ().

When in Running state, QTimeLine also emits the frameChanged () signal when the frame changes.

另请参阅 startFrame (), endFrame (), start ()，和 currentFrame ().

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

若 paused is true, the timeline is paused, causing QTimeLine to enter Paused state. No updates will be signaled until either start () or setPaused(false) is called. If paused is false, the timeline is resumed and continues where it left.

另请参阅 state () 和 start ().

void QTimeLine:: setStartFrame ( int frame )

Sets the start frame, which is the frame corresponding to the start of the timeline (i.e., the frame for which the current value is 0), to frame .

另请参阅 startFrame (), endFrame ()，和 setFrameRange ().

[slot] void QTimeLine:: start ()

Starts the timeline. QTimeLine will enter Running state, and once it enters the event loop, it will update its current time, frame and value at regular intervals. The default interval is 40 ms (i.e., 25 times per second). You can change the update interval by calling setUpdateInterval ().

The timeline will start from position 0, or the end if going backward. If you want to resume a stopped timeline without restarting, you can call resume () 代替。

另请参阅 resume (), updateInterval (), frameChanged ()，和 valueChanged ().

int QTimeLine:: startFrame () const

Returns the start frame, which is the frame corresponding to the start of the timeline (i.e., the frame for which the current value is 0).

另请参阅 setStartFrame () 和 setFrameRange ().

State QTimeLine:: state () const

Returns the state of the timeline.

另请参阅 start (), setPaused ()，和 stop ().

[signal] void QTimeLine:: stateChanged ( QTimeLine::State newState )

此信号被发射每当 QTimeLine 's state changes. The new state is newState .

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

[slot] void QTimeLine:: stop ()

Stops the timeline, causing QTimeLine to enter NotRunning 状态。

另请参阅 start ().

[virtual protected] void QTimeLine:: timerEvent ( QTimerEvent * event )

重实现自 QObject::timerEvent ().

[slot] void QTimeLine:: toggleDirection ()

Toggles the direction of the timeline. If the direction was Forward, it becomes Backward, and vice verca.

另请参阅 setDirection ().

[signal] void QTimeLine:: valueChanged ( qreal value )

QTimeLine emits this signal at regular intervals when in 运行 state, but only if the current value changes. value is the current value. value is a number between 0.0 and 1.0

注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。

另请参阅 QTimeLine::setDuration (), QTimeLine::valueForTime ()，和 QTimeLine::updateInterval .

[virtual] qreal QTimeLine:: valueForTime ( int msec ) const

Returns the timeline value for the time msec . The returned value, which varies depending on the curve shape, is always between 0 and 1. If msec is 0, the default implementation always returns 0.

Reimplement this function to provide a custom curve shape for your timeline.

另请参阅 CurveShape and frameForTime ().