TestCase mouseDrag only clicks item inside Flickable but does not drag - qt

Question

In a QML TestCase, I'm trying to setup automatic scrolling of a ListView that is contained inside a Flickable (to add a custom footer that can be flicked into view, which wouldn't happen with just ListView { footer: Component {} })
However, the mouseDrag only seems to click the correct coordinate, but not drag it to any direction. Here is a simplified version that is as close to the real one as possible:
Implementation.qml
import QtQuick 2.5
FocusScope {
width: 1920
height: 1080
Flickable {
objectName: 'flickableList'
boundsBehavior: Flickable.StopAtBounds
clip: true
width: parent.width
height: 240
contentHeight: 500
ListView {
interactive: false
height: parent.height
width: parent.width
model: ['example1', 'example2', 'example3', 'example4', 'example5']
delegate: Item {
width: 300
height: 100
Text {
text: modelData
}
}
}
}
Item {
id: footer
height: 100
width: parent.width
}
}
TheTest.qml
// The relevant part
var theList = findChild(getView(), 'flickableList')
var startY = 220
var endY = 20
mouseDrag(theList, 100, startY, 100, endY, Qt.LeftButton, Qt.NoModifier, 100)
So, when I'm viewing the UI testrunner, I can see it clearly click on the correct delegate (it has a focus highlight in the actual implementation), ie. the third item "example3", which starts at Y 200 and ends at Y 300). But the drag event never happens. Nothing moves on the screen, and compare(theList.contentY, 200) says it is still at position 0. I would expect it to be at 200, since the mouse is supposed to be mouseDragging from position 220 to 20, ie. scrolling the list down by 200. And 220 is also within the visible height (240).
Just to be sure, I also reversed the Y values, but also no movement:
var theList = findChild(getView(), 'flickableList')
var startY = 20
var endY = 220
mouseDrag(theList, 100, startY, 100, endY, Qt.LeftButton, Qt.NoModifier, 100)
Also, as the 3rd item clearly is clicked on (it gets highlighted), the passed item theList (= the Flickable), should be valid.
Edit:
Oh, and this does scroll the list, but it goes all the way to the bottom of the list (388 px down in the actual implementation, even when the delta is just 30 pixels):
mousePress(theList, startX, startY)
mouseMove(theList, endX, endY)
mouseRelease(theList, endX, endY)
So the question is:
Does mouseDrag only work for specific types of components (ie. does not work on Flickable?), or is there something missing? How can I get it to scroll the list down? Thanks!

Answer 1

Your tag says you're using Qt 5.5 - I would recommend trying Qt 5.14 if possible, as there was a fix that might help:
mouseDrag(): ensure that intermediate moves are done for all drags
[...]
In practice, this means that mouseDrag() never did intermediate moves
(i.e. what happens during a drag in real life) for drags that go from
right to left or upwards.
https://codereview.qt-project.org/c/qt/qtdeclarative/+/281903
If that doesn't help, or upgrading is not an option, I would recommend looking at Qt's own tests (although they are written in C++):
https://code.qt.io/cgit/qt/qtdeclarative.git/tree/tests/auto/quick/qquickflickable/tst_qquickflickable.cpp#n1150

Answer 2

I think mouseDrag only works for mouse area. You could wrap every object with that.
But in the end, you need to use a mouse area inside you delegate and Drag and Drop it.
https://doc.qt.io/qt-5/qml-qtquick-drag.html
import QtQuick 2.5
FocusScope {
width: 1920
height: 1080
Flickable {
objectName: 'flickableList'
boundsBehavior: Flickable.StopAtBounds
clip: true
width: parent.width
height: 240
contentHeight: 500
ListView {
interactive: false
height: parent.height
width: parent.width
model: ['example1', 'example2', 'example3', 'example4', 'example5']
delegate: DelegateList{
textAreaText = modelData
}
}
}
Item {
id: footer
height: 100
width: parent.width
}
}
And the DelegateList.qml
Item {
id: root
property alias textAreaText: textArea.text
width: 300
height: 100
Text {
id: textArea
}
Drag.active: dragArea.drag.active
Drag.hotSpot.x: 10
Drag.hotSpot.y: 10
MouseArea {
id: dragArea
anchors.fill: parent
drag.target: parent
}
}