SpinBoxStyle unable to access button state - qt

Question

SpinBoxStyle from QtQuick.Controls.Styles allows you to change the appearance of a SpinBox, and a part of that is the ability to redesign the up/down arrow buttons. However neither SpinBox nor the style gives you the ability to query the up/down arrow button state, so you can't check if it is pressed or hovered over.
This seems like too much of an oversight, so what part of the API docs have I missed?
I've tried adding a MouseArea to the control delegate itself, but some reason it never receives any events - the controls still work though which suggests that they are 'stealing' the events first.
SpinBox {
style: SpinBoxStyle {
incrementControl: Rectangle {
implicitHeight: 10
implicitWidth: 10
color: "blue"
MouseArea {
anchors.fill: parent
hoverEnabled: true
onEntered: console.log( "Hello" ) // Never printed
}
}
}
}

Answer 1

Apparently you're supposed to use the styleData properties to detect hovered and pressed states, but they aren't documented. Please create a bug report for that.
import QtQuick 2.3
import QtQuick.Controls 1.2
import QtQuick.Controls.Styles 1.2
SpinBox {
style: SpinBoxStyle {
incrementControl: Rectangle {
implicitHeight: 10
implicitWidth: 10
color: styleData.upHovered && !styleData.upPressed
? Qt.lighter("blue") : (styleData.upPressed ? Qt.darker("blue") : "blue")
}
}
}
I'm not sure why the style was implemented this way, but if you look further into the source code, you can see that there are always MouseAreas for the up and down controls. This is very confusing to me; if you're not supposed to provide an interactive control because there will always be MouseAreas shadowing them, why call it incrementControl and decrementControl? Names like increment and decrement might suffice, given that they're not able to receive almost any interaction (clicking works at least, for some reason). If you find this a bit confusing, you may also want to file a separate bug report for the API.
git log --follow -p shows that this code hasn't changed much since the introduction of styles, so I'd say the current implementation (and API) is just outdated, and hopefully there are opportunities for improving this in the future.