TapHandler

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.

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")
   }
}

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")
   }
}

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()
   }
}

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).

If a PointerHandler is disabled, it will reject all events and no signals will be emitted.

The spatial constraint for a tap or long press gesture to be recognized, in addition to the constraint that the release must occur before longPressThreshold has elapsed. If these constraints are not satisfied, the tapped signal is not emitted, and tapCount is not incremented. If the spatial constraint is violated, pressed transitions immediately from true to false, regardless of the time held.

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.

The time in seconds that an event point must be pressed in order to trigger a long press gesture and emit the longPressed() signal. If the point is released before this time limit, a tap can be detected if the gesturePolicy constraint is satisfied. The default value is QStyleHints::mousePressAndHoldInterval() converted to seconds.

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().

The event point currently being handled. When no point is currently being handled, this object is reset to default values (all coordinates are 0).

Holds true whenever the mouse or touch point is pressed, and any movement since the press is compliant with the current gesturePolicy. When the event point is released or the policy is violated, pressed will change to false.

The number of taps which have occurred within the time and space constraints to be considered a single gesture. For example, to detect a triple-tap, you can write:

Rectangle {
    width: 100; height: 30
    signal tripleTap
    TapHandler {
        acceptedButtons: Qt.AllButtons
        onTapped: if (tapCount == 3) tripleTap()
    }
}

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.

The amount of time in seconds that a pressed point has been held, without moving beyond the drag threshold. It will be updated at least once per frame rendered, which enables rendering an animation showing the progress towards an action which will be triggered by a long-press. It is also possible to trigger one of a series of actions depending on how long the press is held.

A value of less than zero means no point is being held within this handler's Item.

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.

This signal is emitted when the target is tapped twice within a short span of time (QStyleHints::mouseDoubleClickInterval) and distance (QPlatformTheme::MouseDoubleClickDistance or QPlatformTheme::TouchDoubleTapDistance). This signal always occurs after singleTapped, tapped and tapCountChanged.

This QML signal was introduced in Qt 5.11.

This signal is emitted when this handler has acquired or relinquished a passive or exclusive grab of the given point.

This signal is emitted when a press occurs that is longer than the long press threshold.

This signal is emitted when the target is tapped once. After an amount of time greater than QStyleHints::mouseDoubleClickInterval, it can be tapped again; but if the time until the next tap is less, tapCount will increase.

This QML signal was introduced in Qt 5.11.

This signal is emitted when the pointer device taps the item.