QScroller ¶

概要 ¶

详细描述 ¶

With kinetic scrolling, the user can push the widget in a given direction and it will continue to scroll in this direction until it is stopped either by the user or by friction. Aspects of inertia, friction and other physical concepts can be changed in order to fine-tune an intuitive user experience.

QScroller object is the object that stores the current position and scrolling speed and takes care of updates. QScroller can be triggered by a flick gesture

QWidget *w = ...;
QScroller::grabGesture(w, QScroller::LeftMouseButtonGesture);
											

or directly like this:

QWidget *w = ...;
QScroller *scroller = QScroller::scroller(w);
scroller->scrollTo(QPointF(100, 100));
											

The scrolled QObjects receive a QScrollPrepareEvent whenever the scroller needs to update its geometry information and a QScrollEvent whenever the content of the object should actually be scrolled.

The scroller uses the global QAbstractAnimation timer to generate its QScrollEvents. This can be changed with FrameRate on a per- QScroller basis.

Several examples in the scroller examples directory show how QScroller , QScrollEvent and the scroller gesture can be used.

Even though this kinetic scroller has a large number of settings available via QScrollerProperties , we recommend that you leave them all at their default, platform optimized values. Before changing them you can experiment with the plot example in the scroller examples directory.

另请参阅

QScrollEvent QScrollPrepareEvent QScrollerProperties

PySide2.QtWidgets.QScroller. State ¶

This enum contains the different QScroller 状态。

常量	描述
QScroller.Inactive	The scroller is not scrolling and nothing is pressed.
QScroller.Pressed	A touch event was received or the mouse button was pressed but the scroll area is currently not dragged.
QScroller.Dragging	The scroll area is currently following the touch point or mouse.
QScroller.Scrolling	The scroll area is moving on it’s own.

PySide2.QtWidgets.QScroller. ScrollerGestureType ¶

This enum contains the different gesture types that are supported by the QScroller gesture recognizer.

常量	描述
QScroller.TouchGesture	The gesture recognizer will only trigger on touch events. Specifically it will react on single touch points when using a touch screen and dual touch points when using a touchpad.
QScroller.LeftMouseButtonGesture	The gesture recognizer will only trigger on left mouse button events.
QScroller.MiddleMouseButtonGesture	The gesture recognizer will only trigger on middle mouse button events.
QScroller.RightMouseButtonGesture	The gesture recognizer will only trigger on right mouse button events.

PySide2.QtWidgets.QScroller. Input ¶

This enum contains an input device agnostic view of input events that are relevant for QScroller .

常量	描述
QScroller.InputPress	The user pressed the input device (e.g. MouseButtonPress , GraphicsSceneMousePress , TouchBegin )
QScroller.InputMove	The user moved the input device (e.g. MouseMove , GraphicsSceneMouseMove , TouchUpdate )
QScroller.InputRelease	The user released the input device (e.g. MouseButtonRelease , GraphicsSceneMouseRelease , TouchEnd )

static PySide2.QtWidgets.QScroller. activeScrollers ( ) ¶

返回类型

Returns an application wide list of currently active QScroller objects. Active QScroller objects are in a state() that is not Inactive . This function is useful when writing your own gesture recognizer.

PySide2.QtWidgets.QScroller. ensureVisible ( rect , xmargin , ymargin ) ¶

参数

• rect – QRectF

• xmargin – qreal

• ymargin – qreal

Starts scrolling so that the rectangle rect is visible inside the viewport with additional margins specified in pixels by xmargin and ymargin around the rect.

In cases where it is not possible to fit the rect plus margins inside the viewport the contents are scrolled so that as much as possible is visible from rect .

The scrolling speed is calculated so that the given position is reached after a platform-defined time span.

This function performs the actual scrolling by calling scrollTo() .

另请参阅

scrollTo()

PySide2.QtWidgets.QScroller. ensureVisible ( rect , xmargin , ymargin , scrollTime ) ¶

参数

• rect – QRectF

• xmargin – qreal

• ymargin – qreal

• scrollTime – int

这是重载函数。

This version will reach its destination position in scrollTime 毫秒。

PySide2.QtWidgets.QScroller. finalPosition ( ) ¶

返回类型

QPointF

Returns the estimated final position for the current scroll movement. Returns the current position if the scroller state is not Scrolling. The result is undefined when the scroller state is Inactive.

The target position is in pixel.

另请参阅

pixelPerMeter() scrollTo()

static PySide2.QtWidgets.QScroller. grabGesture ( target [ , gestureType=TouchGesture ] ) ¶

参数

• target – QObject

• gestureType – ScrollerGestureType

返回类型

GestureType

Registers a custom scroll gesture recognizer, grabs it for the target and returns the resulting gesture type. If scrollGestureType is set to TouchGesture the gesture triggers on touch events. If it is set to one of LeftMouseButtonGesture , RightMouseButtonGesture or MiddleMouseButtonGesture it triggers on mouse events of the corresponding button.

Only one scroll gesture can be active on a single object at the same time. If you call this function twice on the same object, it will ungrab the existing gesture before grabbing the new one.

注意

To avoid unwanted side-effects, mouse events are consumed while the gesture is triggered. Since the initial mouse press event is not consumed, the gesture sends a fake mouse release event at the global position (INT_MIN, INT_MIN) . This ensures that internal states of the widget that received the original mouse press are consistent.

另请参阅

ungrabGesture() grabbedGesture()

static PySide2.QtWidgets.QScroller. grabbedGesture ( target ) ¶

参数

target – QObject

返回类型

GestureType

Returns the gesture type currently grabbed for the target or 0 if no gesture is grabbed.

另请参阅

grabGesture() ungrabGesture()

PySide2.QtWidgets.QScroller. handleInput ( input , position [ , timestamp=0 ] ) ¶

参数

• input – Input

• position – QPointF

• timestamp – qint64

返回类型

bool

This function is used by gesture recognizers to inform the scroller about a new input event. The scroller changes its internal state() according to the input event and its attached scroller properties. The scroller doesn’t distinguish between the kind of input device the event came from. Therefore the event needs to be split into the input type, a position and a milli-second timestamp 。 position needs to be in the target’s coordinate system.

返回值为 true if the event should be consumed by the calling filter or false if the event should be forwarded to the control.

注意

使用 grabGesture() should be sufficient for most use cases.

static PySide2.QtWidgets.QScroller. hasScroller ( target ) ¶

参数

target – QObject

返回类型

bool

返回 true if a QScroller object was already created for target ; false 否则。

另请参阅

scroller()

PySide2.QtWidgets.QScroller. pixelPerMeter ( ) ¶

返回类型

QPointF

Returns the pixel per meter metric for the scrolled widget.

The value is reported for both the x and y axis separately by using a QPointF .

注意

Please note that this value should be physically correct. The actual DPI settings that Qt returns for the display may be reported wrongly on purpose by the underlying windowing system, for example on macOS.

PySide2.QtWidgets.QScroller. resendPrepareEvent ( ) ¶

This function resends the QScrollPrepareEvent . Calling triggers a QScrollPrepareEvent from the scroller. This allows the receiver to re-set content position and content size while scrolling. Calling this function while in the Inactive state is useless as the prepare event is sent again before scrolling starts.

PySide2.QtWidgets.QScroller. scrollTo ( pos ) ¶

参数

pos – QPointF

Starts scrolling the widget so that point pos is at the top-left position in the viewport.

The behaviour when scrolling outside the valid scroll area is undefined. In this case the scroller might or might not overshoot.

The scrolling speed will be calculated so that the given position will be reached after a platform-defined time span.

pos is given in viewport coordinates.

另请参阅

ensureVisible()

PySide2.QtWidgets.QScroller. scrollTo ( pos , scrollTime ) ¶

参数

• pos – QPointF

• scrollTime – int

这是重载函数。

This version will reach its destination position in scrollTime 毫秒。

static PySide2.QtWidgets.QScroller. scroller ( target ) ¶

参数

target – QObject

返回类型

QScroller

Returns the scroller for the given target . As long as the object exists this function will always return the same QScroller instance. If no QScroller exists for the target , one will implicitly be created. At no point more than one QScroller will be active on an object.

另请参阅

hasScroller() target()

static PySide2.QtWidgets.QScroller. scroller ( target ) ¶

参数

target – QObject

返回类型

QScroller

这是重载函数。

This is the const version of scroller() .

PySide2.QtWidgets.QScroller. scrollerProperties ( ) ¶

返回类型

QScrollerProperties

另请参阅

setScrollerProperties()

PySide2.QtWidgets.QScroller. scrollerPropertiesChanged ( arg__1 ) ¶

参数

arg__1 – QScrollerProperties

PySide2.QtWidgets.QScroller. setScrollerProperties ( prop ) ¶

参数

prop – QScrollerProperties

另请参阅

scrollerProperties()

PySide2.QtWidgets.QScroller. setSnapPositionsX ( positions ) ¶

参数

positions –

Set the snap positions for the horizontal axis to a list of positions . This overwrites all previously set snap positions and also a previously set snapping interval. Snapping can be deactivated by setting an empty list of positions.

PySide2.QtWidgets.QScroller. setSnapPositionsX ( first , interval ) ¶

参数

• first – qreal

• interval – qreal

Set the snap positions for the horizontal axis to regular spaced intervals. The first snap position is at first . The next at first + interval . This can be used to implement a list header. This overwrites all previously set snap positions and also a previously set snapping interval. Snapping can be deactivated by setting an interval of 0.0

PySide2.QtWidgets.QScroller. setSnapPositionsY ( positions ) ¶

参数

positions –

Set the snap positions for the vertical axis to a list of positions . This overwrites all previously set snap positions and also a previously set snapping interval. Snapping can be deactivated by setting an empty list of positions.

PySide2.QtWidgets.QScroller. setSnapPositionsY ( first , interval ) ¶

参数

• first – qreal

• interval – qreal

Set the snap positions for the vertical axis to regular spaced intervals. The first snap position is at first . The next at first + interval . This overwrites all previously set snap positions and also a previously set snapping interval. Snapping can be deactivated by setting an interval of 0.0

PySide2.QtWidgets.QScroller. state ( ) ¶

返回类型

State

PySide2.QtWidgets.QScroller. stateChanged ( newstate ) ¶

参数

newstate – State

PySide2.QtWidgets.QScroller. stop ( ) ¶

Stops the scroller and resets its state back to Inactive.

PySide2.QtWidgets.QScroller. target ( ) ¶

返回类型

QObject

Returns the target object of this scroller.

另请参阅

hasScroller() scroller()

static PySide2.QtWidgets.QScroller. ungrabGesture ( target ) ¶

参数

target – QObject

Ungrabs the gesture for the target . Does nothing if no gesture is grabbed.

另请参阅

grabGesture() grabbedGesture()

PySide2.QtWidgets.QScroller. velocity ( ) ¶

返回类型

QPointF

Returns the current scrolling velocity in meter per second when the state is Scrolling or Dragging. Returns a zero velocity otherwise.

The velocity is reported for both the x and y axis separately by using a QPointF .

另请参阅

pixelPerMeter()