I am using a ComboBox in QML and when populated with a lot of data it exceeds my main windows bottom boarder. From googling I have learned that the drop-down list of a ComboBox is put on top of the current application window and therefore it does not respect its boundaries.
Ideally I would want the ComboBox to never exceed the main applications boundary, but I can not find any property in the documentation.
A different approach would be to limit the number of visible items of the drop-down list so that it do not exceed the window limits for a given window geometry. I was not able to find this in the documentation either and I have run out of ideas.
Take a look to the ComboBox source code, the popup is of a Menu type and it doesn't have any property to limit its size. Moreover, the z property of the Menu is infinite, i.e. it's always on top.
If you Find no way but to use the ComboBox of Qt you can create two models one for visual purpose, I will call it visual model, you will show it in your ComboBox and the complete one , it will be the reference model. Items count in your VisualModel wil be equal to some int property maximumComboBoxItemsCount that you declare . you'll need o find a way that onHovered find the index under the mouse in the visualmodel if it's === to maximumComboBoxIemsCount you do visualModel.remove(0) et visualModel.add(referenceModel.get(maximum.. + 1) and you'll need another property minimumComboBoxIemsCount, same logic but for Scroll Up , I dont know if it will work. but it's an idea
I think there is no solution using the built-in component and you should create your own comboBox. You can start from the following code.
import QtQuick 2.0
Item {
id: comboBox
property string initialText
property int maxHeight
property int selectedItem:0
property variant listModel
signal expanded
signal closed
// signal sgnSelectedChoice(var choice)
width: 100
height: 40
ComboBoxButton {
id: comboBoxButton
width: comboBox.width
height: 40
borderColor: "#fff"
radius: 10
margin: 5
borderWidth: 2
text: initialText
textSize: 12
onClicked: {
if (listView.height == 0)
{
listView.height = Math.min(maxHeight, listModel.count*comboBoxButton.height)
comboBox.expanded()
source = "qrc:/Images/iconUp.png"
}
else
{
listView.height = 0
comboBox.closed()
source = "qrc:/Images/iconDown.png"
}
}
}
Component {
id: comboBoxDelegate
Rectangle {
id: delegateRectangle
width: comboBoxButton.width
height: comboBoxButton.height
color: "#00000000"
radius: comboBoxButton.radius
border.width: comboBoxButton.borderWidth
border.color: comboBoxButton.borderColor
Text {
color: index == listView.currentIndex ? "#ffff00" : "#ffffff"
anchors.centerIn: parent
anchors.margins: 3
font.pixelSize: 12
text: value
font.bold: true
}
MouseArea {
anchors.fill: parent
onClicked: {
listView.height = 0
listView.currentIndex = index
comboBox.selectedItem = index
tools.writePersistence(index,5)
comboBoxButton.text = value
comboBox.closed()
}
}
}
}
ListView {
id: listView
anchors.top: comboBoxButton.bottom
anchors.left: comboBoxButton.left
width: parent.width
height: 0
clip: true
model: listModel
delegate: comboBoxDelegate
currentIndex: selectedItem
}
onClosed: comboBoxButton.source = "qrc:/Images/iconDown.png"
Component.onCompleted: {
var cacheChoice = tools.getPersistence(5);
listView.currentIndex = tools.toInt(cacheChoice)
selectedItem = listView.currentIndex
comboBoxButton.text = cacheModel.get(selectedItem).value
}
}
import QtQuick 2.0
Item {
id: container
signal clicked
property string text
property alias source : iconDownUp.source
property string color: "#ffffff"
property int textSize: 12
property string borderColor: "#00000000"
property int borderWidth: 0
property int radius: 0
property int margin: 0
Rectangle {
id: buttonRectangle
anchors.fill: parent
color: "#00000000"
radius: container.radius
border.width: container.borderWidth
border.color: container.borderColor
Image {
id: image
anchors.fill: parent
source: "qrc:/Images/buttonBackground.png"
Image {
id: iconDownUp
source: "qrc:/Images/iconDown.png"
sourceSize.height:20
sourceSize.width: 20
anchors.verticalCenter: parent.verticalCenter
}
}
Text {
id:label
color: container.color
anchors.centerIn: parent
font.pixelSize: 10
text: container.text
font.bold: true
}
MouseArea {
id: mouseArea;
anchors.fill: parent
onClicked: {
container.clicked()
buttonRectangle.state = "pressed"
startTimer.start()
}
}
Timer{
id:startTimer
interval: 200
running: false;
repeat: false
onTriggered: buttonRectangle.state = ""
}
states: State {
name: "pressed"
when: mouseArea.pressed
PropertyChanges { target: image; scale: 0.7 }
PropertyChanges { target: label; scale: 0.7 }
}
transitions: Transition {
NumberAnimation { properties: "scale"; duration: 200; easing.type: Easing.InOutQuad }
}
}
}
I've used it in some software of mine, hence it is possible that It could not work "out of the box". I use it like this:
ComboBox{
id:cacheChoice
initialText: "None"
anchors.top: baseContainer.top
anchors.topMargin: 2
anchors.right: baseContainer.right
maxHeight: 500
listModel: cacheModel
onExpanded: {
cacheChoice.height = 500
}
onClosed: {
cacheChoice.height = 20
}
}