Abstract handler for single-point Pointer Events. More...
Import Statement: | import Qt.labs.handlers 1.0 |
Inherits: | |
Inherited By: |
An intermediate class (not registered as a QML type) for the most common handlers: those which expect only a single point. wantsPointerEvent() will choose the first point which is inside the target item, and return true as long as the event contains that point. Override handleEventPoint() to implement a single-point handler.
acceptedButtons : int |
The mouse buttons which can activate this Pointer Handler.
By default, this property is set to Qt.LeftButton. It can be set to an OR combination of mouse buttons, and will ignore events from other buttons.
For example, a control could be made to respond to left and right clicks in different ways, with two handlers:
Item { TapHandler { onTapped: console.log("left clicked") } TapHandler { acceptedButtons: Qt.RightButton onTapped: console.log("right clicked") } }
Note: Tapping on a touchscreen or tapping the stylus on a graphics tablet emulates clicking the left mouse button. This behavior can be altered via acceptedDevices or acceptedPointerTypes.
acceptedDevices : int |
The types of pointing devices that can activate this Pointer Handler.
By default, this property is set to PointerDevice.AllDevices. If you set it to an OR combination of device types, it will ignore events from non-matching devices.
For example, a control could be made to respond to mouse and stylus clicks in one way, and touchscreen taps in another way, with two handlers:
Item { TapHandler { acceptedDevices: PointerDevice.Mouse | PointerDevice.Stylus onTapped: console.log("clicked") } TapHandler { acceptedDevices: PointerDevice.TouchScreen onTapped: console.log("tapped") } }
acceptedModifiers : int |
If this property is set, it will require the given keyboard modifiers to be pressed in order to react to pointer events, and otherwise ignore them.
If this property is set to Qt.KeyboardModifierMask
(the default value), then the PointerHandler ignores the modifier keys.
For example, an Item could have two handlers of the same type, one of which is enabled only if the required keyboard modifiers are pressed:
Item { TapHandler { acceptedModifiers: Qt.ControlModifier onTapped: console.log("control-tapped") } TapHandler { acceptedModifiers: Qt.NoModifier onTapped: console.log("tapped") } }
acceptedPointerTypes : int |
The types of pointing instruments (finger, stylus, eraser, etc.) that can activate this Pointer Handler.
By default, this property is set to PointerDevice.AllPointerTypes. If you set it to an OR combination of device types, it will ignore events from non-matching events.
For example, a control could be made to respond to mouse, touch, and stylus clicks in some way, but delete itself if tapped with an eraser tool on a graphics tablet, with two handlers:
Rectangle { id: rect TapHandler { acceptedPointerTypes: PointerDevice.GenericPointer | PointerDevice.Finger | PointerDevice.Pen onTapped: console.log("clicked") } TapHandler { acceptedPointerTypes: PointerDevice.Eraser onTapped: rect.destroy() } }
[read-only] active : bool |
This holds true whenever this PointerHandler has taken sole responsibility for handing one or more EventPoints, by successfully taking an exclusive grab of those points. This means that it is keeping its properties up-to-date according to the movements of those Event Points and actively manipulating its target (if any).
enabled : bool |
If a PointerHandler is disabled, it will reject all events and no signals will be emitted.
grabPermission : bool |
This property specifies the permissions when this handler's logic decides to take over the exclusive grab, or when it is asked to approve grab takeover or cancellation by another handler.
The default is CanTakeOverFromItems | CanTakeOverFromHandlersOfDifferentType | ApprovesTakeOverByAnything
which allows most takeover scenarios but avoids e.g. two PinchHandlers fighting over the same
touchpoints.
[read-only] parent : Item |
The Item which is the scope of the handler; the Item in which it was declared. The handler will handle events on behalf of this Item, which means a pointer event is relevant if at least one of its event points occurs within the Item's interior. Initially target() is the same, but it can be reassigned.
See also target and QObject::parent().
[read-only] point : HandlerPoint |
The event point currently being handled. When no point is currently being handled, this object is reset to default values (all coordinates are 0).
target : Item |
The Item which this handler will manipulate.
By default, it is the same as the parent, the Item within which the handler is declared. However, it can sometimes be useful to set the target to a
different Item, in order to handle events within one item but manipulate another; or to null
, to disable the default behavior and do something else instead.
canceled(EventPoint point) |
If this handler has already grabbed the given point, this signal is emitted when the grab is stolen by a different Pointer Handler or Item.
grabChanged(EventPoint point) |
This signal is emitted when this handler has acquired or relinquished a passive or exclusive grab of the given point.