How to drag an item outside a ListView in QML - qt

I am developing a QML application which basically contains two ListView. I would like to copy a QML item from one ListView to another. I tried to handle this by setting Drag property in the delegate but the item cannot go outside the view when I drag the item, I think the Flickable container handles mouse events.
So, I want to try the following:
create a mousearea which overlaps the to ListView
create a new object by calling **createComponent() / createObject()**
reparent this object to the mousearea
handle mouse events in the mousearea till drop
This solution seems to me a little complicated, so do you have a better way to achieve this ?
This was a bad idea and too much complicated. I think I got a way to achieve this:
each delegate of the ListView has a hidden Item which can be dragged,
as my ListView are in a reusable component, I use a property to pass a higher item (a Rectangle here and NOT a **MouseArea**) which can be used as parent for dragged items,
the higher item contains the two ListView (and maybe more in the future),
when the drag begins, the item is set to visible and reparented using a **State**
So, I missed the point that set the parent should solve my problem.

Next code is just an idea, but the key is to have a MouseArea inside a delegate for the first ListView so the user can drag the items and drop them into a DropArea which belongs to the second ListView.
In this example, model is very simple, just a number. And when the item is dropped, it is removed from the first ListView:
listView.model.remove(listView.dragItemIndex)
Just remove that line of code to copy the item instead of removing.
main.qml
import QtQuick 2.5
import QtQuick.Window 2.2
Window {
visible: true
width: 600
height: 600
Rectangle {
id: root
width: 400
height: 400
ListView {
id: listView
width: parent.width / 2
height: parent.height
property int dragItemIndex: -1
model: ListModel {
Component.onCompleted: {
for (var i = 0; i < 10; ++i) {
append({value: i});
}
}
}
delegate: Item {
id: delegateItem
width: listView.width
height: 50
Rectangle {
id: dragRect
width: listView.width
height: 50
anchors.horizontalCenter: parent.horizontalCenter
anchors.verticalCenter: parent.verticalCenter
color: "salmon"
border.color: Qt.darker(color)
Text {
anchors.centerIn: parent
text: modelData
}
MouseArea {
id: mouseArea
anchors.fill: parent
drag.target: dragRect
drag.onActiveChanged: {
if (mouseArea.drag.active) {
listView.dragItemIndex = index;
}
dragRect.Drag.drop();
}
}
states: [
State {
when: dragRect.Drag.active
ParentChange {
target: dragRect
parent: root
}
AnchorChanges {
target: dragRect
anchors.horizontalCenter: undefined
anchors.verticalCenter: undefined
}
}
]
Drag.active: mouseArea.drag.active
Drag.hotSpot.x: dragRect.width / 2
Drag.hotSpot.y: dragRect.height / 2
}
}
}
ListView {
id: listView2
width: parent.width / 2
height: parent.height
anchors.right: parent.right
property int dragItemIndex: -1
DropArea {
id: dropArea
anchors.fill: parent
onDropped: {
listView2.model.append(listView.model.get(listView.dragItemIndex))
listView.model.remove(listView.dragItemIndex)
listView.dragItemIndex = -1;
}
}
model: ListModel {
Component.onCompleted: {
for (var i = 0; i < 1; ++i) {
append({value: i});
}
}
}
delegate: Item {
id: delegateItem2
width: listView2.width
height: 50
Rectangle {
id: dragRect2
width: listView2.width
height: 50
anchors.horizontalCenter: parent.horizontalCenter
anchors.verticalCenter: parent.verticalCenter
color: "salmon"
border.color: Qt.darker(color)
Text {
anchors.centerIn: parent
text: modelData
}
}
}
}
}
}

Related

Looking for alternate function to QML ListView's itemAtIndex due to version conflict

I'm using Qt 5.12, so I can't access ListView's itemAtIndex which was introduced in Qt 5.13.
I can't upgrade Qt due to my project/platform related restrictions. Is there a way to find the item at a given index for ListView with the Qt versions prior to 5.13?
Otherwise, is there a way to get mouse positions of an item based on index?
I'm having a listview with adjacent items having different width(alternate items have same width). I'm trying to access listview's item which is of less width compared to the adjacent item. The space between two items in the above picture is also an item which is marked as dummy. I'm able to get the index of each item (both actual & dummy), but the x position I get seems to be incorrect as the rectangle cursor is not getting placed in the intended item's position.
Please suggest alternatives that gives the similar functionality as itemAtIndex. Thanks.
In the following example, I declare a MouseArea in each delegate. So, once the mouse hovers over that delegate, we trigger MouseArea.onEntered and can know which item, because that delegate will have the corresponding index value:
import QtQuick
import QtQuick.Controls
import QtQuick.Layouts
Page {
background: Rectangle { color: "#848895" }
ColumnLayout {
anchors.fill: parent
ListView {
id: listView
Layout.fillWidth: true
Layout.preferredHeight: 150
model: 20
orientation: ListView.Horizontal
delegate: MyDelegate { }
ScrollBar.horizontal: ScrollBar {
height: 20
policy: ScrollBar.AlwaysOn
}
highlight: Item {
z: 2
Rectangle {
width: 10
height: parent.height
color: "lightsteelblue"
border.color: "black"
}
}
}
Item {
Layout.fillWidth: true
Layout.fillHeight: true
Frame {
anchors.centerIn: parent
background: Rectangle { }
Text {
text: qsTr("ListView.currentIndex = %1").arg(listView.currentIndex)
}
}
}
}
}
// MyDelegate.qml
import QtQuick
import QtQuick.Controls
Rectangle {
property ListView listView: ListView.view
width: 120
height: listView.height - 20
implicitWidth: width
implicitHeight: height
color: "transparent"
Rectangle {
border.color: "grey"
color: "white"
y: 20
height: parent.height - y * 2
width: parent.width
Text {
anchors.centerIn: parent
text: qsTr("Item %1").arg(modelData + 1)
}
}
MouseArea {
anchors.fill: parent
hoverEnabled: true
onEntered: listView.currentIndex = index
}
}
You can Try it Online!

How to get the list of QML Column Layout children?

I am working on some QML + c++ project and, I have a little problem with QML layouts:
I have two custom components :
First one: is a side-bar "SideTabBar.qml" (the purple rectangle in the image below).
Second one: is the element in the side-bar "SideBarElement.qml".
This image describes what I am talking about:
What I want is: highlight each side bar element on click.
To do so I am trying to iterate over the columnLayout children and lowlight them excepting the clicked one. But, I have not managed to make it works.
SideTabBar.qml:
Item {
id: sideTabBar
width: 70
height: parent.height
property string activeElement: ""
ColumnLayout{
id:sidebarLayout
anchors.fill: parent
spacing:2
SideBarElement{elementId:"a1";image:"../assets/product.svg"}
SideBarElement{elementId:"a2";image:"../assets/product.svg"}
Item {Layout.fillHeight: true}
}
}
SideBarElement.qml:
Item {
property alias image: sideBarElementicon.source
property string elementId: ""
id: sideBarElement
width:parent.width
Layout.preferredHeight: 70
Layout.alignment: Qt.AlignTop
Rectangle{
anchors.fill: parent
color:Qt.rgba(0,0,0,0)
}
Image {
id: sideBarElementicon
source: "genericIcon.png"
anchors.horizontalCenter: parent.horizontalCenter
anchors.verticalCenter: parent.verticalCenter
width: 50
height: 50
}
MouseArea{
anchors.fill: parent
onClicked:{ sideTabBar.activeElement = elementId
// compiler does not even enter this loop.
// for(var child in Layout.children){
// console.log("this is a child")
// }
}
}
}
In this case it is better to work with a Repeater since it has an associated index and use a model to set the properties:
SideBarElement.qml
import QtQuick 2.0
Item {
property alias icon: sideBarElementicon.source
property bool highlight: false
width: parent.width
Rectangle{
anchors.fill: parent
color: highlight ? Qt.rgba(1,1,0,1) : Qt.rgba(0,0,0,0)
}
Image {
id: sideBarElementicon
source: "genericIcon.png"
anchors.horizontalCenter: parent.horizontalCenter
anchors.verticalCenter: parent.verticalCenter
width: 50
height: 50
}
}
SideTabBar.qml
import QtQuick 2.0
import QtQuick.Layouts 1.11
Item {
id: sideTabBar
width: 70
height: parent.height
property int currentIndex: -1
ListModel{
id: elements
ListElement {
image: "../assets/product.svg"
}
ListElement {
image: "../assets/product.svg"
}
ListElement {
image: "../assets/product.svg"
}
ListElement {
image: "../assets/product.svg"
}
ListElement {
image: "../assets/product.svg"
}
ListElement {
image: "../assets/product.svg"
}
}
Rectangle{
anchors.fill: parent
color: "purple"
}
ColumnLayout{
id:sidebarLayout
anchors.fill: parent
spacing:2
Repeater{
model: elements
SideBarElement{
id: element
highlight: ix == currentIndex
icon: image
property int ix: index
Layout.preferredHeight: 70
Layout.alignment: Qt.AlignTop
MouseArea{
anchors.fill: parent
onClicked: currentIndex = ix
}
}
}
Item {Layout.fillHeight: true}
}
}

ListView dynamic anchoring

Let us suppose I have a card made using Rectangle and I want to show buttons on top of it when clicked. I'm calling showMenu() function to do that and for buttons I'm using an ListView with dynamic ListModel. The problem with such is that the button gets added bellow the Rectangle instead of the top of it. The anchor is not updating after appending an item to the model. Here is my code
Item {
width: 120
height: 120
Rectangle {
id: card
width: 50
height: 100
color: "pink"
anchors.bottom: parent.bottom
Item {
id: rec
width: 50
anchors.bottom: parent.top // This anchor is not updating after appending an item to the list.
ListModel {
id: menuListModel
}
Component {
id: delegate
Rectangle {
width: 120
height: 20
color: "blue"
Text {
anchors.fill: parent
anchors.centerIn: parent
text: commandText
}
}
}
ListView {
anchors.fill: parent
model:menuListModel
delegate: delegate
interactive: false
}
}
MouseArea {
anchors.fill: parent
onClicked: menuListModel.append({"commandText" : "Normal Summon"});
}
}
}
This is more or less a duplicate of this question. The Item needs a height. As mentioned in the answer to that question, you can add debug statements to the code when things like this happen. In this situation, you can also add a Rectangle as a child of the Item and make sure that it's visible:
Rectangle {
anchors.fill: parent
color: "transparent"
border.color: "darkorange"
}
If it's not visible, you know that the problem lies with that (parent) item.

Why does anchors.fill does not work in a QML ListView's delegate's subviews, and what is a nice solution?

I encountered this:
ListView {
id: listView
model: ["Lorem","Ipsum"]
delegate: Item {
height: 20
Text {
z: 2
text: modelData
anchors.fill: parent
}
Rectangle {
z: 1
color: "red"
// this does not work:
anchors.fill: parent
// this works, but I have mixed feelings about it:
// height: 20; width: listView.width
}
}
}
So, apparently, anchors do not work in a delegate's subitem (in this case, Rectangle is not displayed at all). I would like to understand the mechanism behind this. Also, I'd like to ask what is the preferred way to deal with this situation?
Thank You!
Item has an implicitWidth and implicitHeight of zero, so making your Rectangle and Text fill it will result in them having no size as well.
There are two things wrong with your code:
The ListView has no width or height specified.
Your delegate has no width specified.
Here's one way of doing it correctly:
import QtQuick 2.0
import QtQuick.Window 2.0
Window {
width: 300
height: 300
visible: true
ListView {
id: listView
anchors.fill: parent
model: ["Lorem","Ipsum"]
delegate: Item {
width: listView.width
height: textItem.implicitHeight
Text {
id: textItem
z: 2
text: modelData
width: parent.width
}
Rectangle {
z: 1
color: "red"
anchors.fill: parent
}
}
}
}
The documentation of ListView has more information.

Qt, QML ListView and Desktop App

My question is kind of a two part conditional question. I have a desktop application I'm writing in C++/Qt. In the app I have a couple lists that I want to decorate and add list items with icons and rich text.
I first attempted to do this with the QWidget world but the more I looked into it, the more I thought QML might be a better option. But now I'm wondering about that as well since it seems that QML Is more geared toward touch screen devices. Not to mention that my progress with QML has been frusating. Give them QML below, I cannot figure out how to: (1) get an item to highlight when I click it and (2) add a scroll bar:
import QtQuick 1.0
Item
{
width: 300
height: 200
ListModel
{
id: myModel2
ListElement { text: "List Item 1" }
ListElement { text: "List Item 2" }
ListElement { text: "List Item 3" }
ListElement { text: "List Item 4" }
ListElement { text: "List Item 5" }
ListElement { text: "List Item 6" }
}
Component
{
id: beerDelegate
Rectangle
{
id: beerDelegateRectangle
height: beerDelegateText.height * 1.5
width: parent.width
Text
{
id: beerDelegateText
text: "<b>" + modelData + "</b> <i>(" + modelData + ")</i>"
}
MouseArea
{
anchors.fill: parent
onClicked:
{
console.log("clicked: " + modelData + " at index: " + index);
beerList.currentIndex = index;
}
}
}
}
ListView
{
id: beerList
anchors.fill: parent
model: myModel2
delegate: beerDelegate
highlightFollowsCurrentItem: true
highlight: Rectangle
{
width: parent.width
color: "red"
}
focus: true
}
}
How can I accomplish what I'm looking for given this QML? Or is using QML in a QWidget desktop app just a bad idea all around?
For the first question (highlight):
Your list actually draws the highlight, however, your item delegate overpaints this with a white rectangle! Just replace the rectangle with an item and it works:
Component
{
id: beerDelegate
Item
{
...
}
}
For the second question (scroll bars):
As far as I know, QML doesn't provide scroll bars out of the box. There is however the Qt Desktop Components project (git repository) which gives you access to most of the widgets in the QML world. Among them, there is a ScrollArea.
It is no longer necessary to implement the Scrollbars yourself. There is the ScrollView-Item since Qt 5.1. Simply surround a Flickable-Item (e.g. the ListView-Item you use, is also "Flickable") with the ScrollView-Item and you'll be fine:
ScrollView {
ListView {
id: beerList
anchors.fill: parent
model: myModel2
delegate: beerDelegate
highlightFollowsCurrentItem: true
highlight: Rectangle
{
width: parent.width
color: "red"
}
focus: true
}
}
For the second question. i.e Scroll-bar on ListView:
I have created code for scroll bar on ListView. It also can work on the GridView
ScrollBar.qml
import Qt 4.7
Item {
property variant target
width: 8
anchors.top: target.top
anchors.bottom: target.bottom
anchors.margins: 1
anchors.rightMargin: 2
anchors.bottomMargin: 2
anchors.right: target.right
visible: (track.height == slider.height) ? false : true
Image {
id: scrollPath
width: 2
anchors.top: parent.top
anchors.bottom: parent.bottom
anchors.horizontalCenter: parent.horizontalCenter
source: "qrc:/resources/buttons/slider2.png"
}
Item {
anchors.fill: parent
Timer {
property int scrollAmount
id: timer
repeat: true
interval: 20
onTriggered: {
target.contentY = Math.max(0, Math.min(target.contentY + scrollAmount,
target.contentHeight - target.height));
}
}
Item {
id: track
anchors.top: parent.top
anchors.topMargin: 1
anchors.bottom: parent.bottom
width: parent.width
MouseArea {
anchors.fill: parent
onPressed: {
timer.scrollAmount = target.height * (mouseY < slider.y ? -1 : 1)
timer.running = true;
}
onReleased: {
timer.running = false;
}
}
Image {
id:slider
anchors.horizontalCenter: parent.horizontalCenter
source: "qrc:/resources/buttons/slider.png"
width: parent.width
height: Math.min(target.height / target.contentHeight * track.height, track.height) < 20 ? 20 : Math.min(target.height / target.contentHeight * track.height, track.height)
y: target.visibleArea.yPosition * track.height
MouseArea {
anchors.fill: parent
drag.target: parent
drag.axis: Drag.YAxis
drag.minimumY: 0
drag.maximumY: track.height - height
onPositionChanged: {
if (pressedButtons == Qt.LeftButton) {
target.contentY = slider.y * target.contentHeight / track.height;
}
}
}
}
}
}
}
And I used scroll bar item with ListView in MyListView.qml as:
MyListView.qml
ListView {
id: list
clip: true
anchors.margins: 5
anchors.fill: parent
model: 10
delegate: trackRowDelegate
interactive: contentHeight > height
}
ScrollBar {
id: verticalScrollBar
target: list
clip: true
}
This ScrollBar item can be used with GridView as
GridView {
id: grid
clip: true
anchors.margins: 5
anchors.fill: parent
cellWidth:100
cellHeight: 100
model: items
interactive: contentHeight > height
snapMode: GridView.SnapToRow
delegate: myDelegate
}
ScrollBar {
id: verticalScrollBar
target: grid
clip: true
visible: grid.interactive
}

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