i want to add a Component dynamically to an ColumnLayout in a TabView/Tab. But i've not found a possibility to do this. The problem is that i have no correct parent reference to my ColumnLayout for the createObject call.
Because the Tab dynamically loads a Component I've encapsulated the ColumnLayout in a Component.
In the QML Debugger i can solve the following path: objForm.tabView.tabStatus.tabStatusLoader.colLayout, but i cant use this as an correct parent.
It seems not be in the scope.
TypeError: Cannot read property 'tabStatus' of undefined
ObjForm.ui.qml
Item {
id: item1
width: 400
height: 400
property QtObject object
property Component compLayout
TabView {
id: tabView
anchors.fill: parent
Tab {
id: tabStatus
title: "status"
Loader {
id: tabStatusLoader
sourceComponent: compLayout
}
}
}
}
ObjForm.qml
ObjectViewForm {
id: objForm
anchors.fill: parent
object: someObj
compLayout: Component {
id: layoutComp
ColumnLayout {
id: colLayout
spacing: 2
}
}
onObjectChanged: {
// Here i want to add the someLabel Component to the ColumnLayout
someLabel.createObject(*PARENT*)
}
Component {
id: someLabel
Row {
property string text
property string label
spacing: 5
Label {
text: parent.label
}
Label {
text: parent.text
}
}
}
Does anyone know how to solve this or can make a better suggestion?
ok I've found a solution by myself. Instead to include the ColumnLayout into the Component, i've pulled it out and made an alias property to publish it. With this it was possible to add objects to my ColumnLayout. But the ColumnLayout got the wrong parent(objForm) instead of the Component.
A Component cant be a parent because a QQuickItem* is expected instead of a QObject* and additional can't include properties except for 'id'. Therefore a dummy Item was needed.
To reparent the ColumnLayout the Item needs a Component.onCompleted function where the parent will be set.
ObjectViewForm {
id: objForm
anchors.fill: parent
object: someObj
property alias componentLayout: colLayout
compLayout: Component {
id: layoutComp
Item {
id: dummy
Component.onCompleted: {
colLayout.parent = dummy
}
}
}
ColumnLayout {
id: colLayout
spacing: 2
}
Related
I have a screen with some rectangles which can contain text. The text content of these rectangles should be allowed to change through clicking on buttons in the screen where this component is used. The problem I am having is how to know in the screen which uses this component which instance is selected. I thought about solving this via emitting a signal, which transmits the id of the instance as reference, but it seems this does not work. How could this be accomplished? Here my custom rectangle component
Rectangle {
id: root
width: 50
height: 50
color: "#000000"
anchors.verticalCenter: parent.verticalCenter
border.color: "#555555"
property int value: 0
signal sendId(Item)
Text {
id: displayed_text
color: "#ffffff"
text: root.value
anchors.horizontalCenter: parent.horizontalCenter
anchors.verticalCenter: parent.verticalCenter
horizontalAlignment: Text.AlignHCenter
verticalAlignment: Text.AlignVCenter
font.pixelSize: 15
}
MouseArea {
id: mouseArea
anchors.fill: parent
onClicked: {
root.border.color="#222222"
root.sendId(root.id)
}
}
}
and here the file where other buttons should change the content of the custom component:
property Item selected: myRectangle
function changeSelected(value) {
selected.value=5
}
function setSelected(it) {
root.selected=it
}
MyRectangle {
id: myRectangle
Component.onCompleted: {
myRectangle.sendId.connect(tempNumber.setSelected)
}
}
MyRectangle {
id: myRectangle1
Component.onCompleted: {
myRectangle1.sendId.connect(tempNumber.setSelected)
}
}
MyRectangle {
id: myRectangle2
Component.onCompleted: {
myRectangle2.sendId.connect(tempNumber.setSelected)
}
}
root.sendId(root.id)
The id is not a regular property. Don't use it as such. The purpose of the id is to get you a reference, with which you can refer to a particular object, so all you really need is:
root.sendId(root)
And if root is your qml file root object, sendId(root) would work too as long as sendId is not shadowed, root members can be referenced directly, keep in mind this only applies to the root object, it won't work for a object that is a direct or indirect parent but not root.
It is recomended practice to abstain from giving everything an id - only use ids when you really need to reference a particular object and no other way exists.
Another thing you are missing is that unlike JS functions, you do have to provide some typing for a signal. You can still use var and pass anything, but usually it is more efficient to narrow down the scope. So you need type and identifier:
signal sendId(Item item)
This way you can access item in the signal handlers, so you can avoid the awkward imperative connection syntax, so instead you can simply:
MyRectangle {
onSendId: tempNumber.setSelected(item)
}
However, I'd say your design is not optional. Signals are supposed to be employed when you aim for generality and reuse. Your usage scenario is more specific, thus the usage of signals can be avoided altogether:
// Rect.qml
Rectangle {
width: 50
height: 50
color: manager.selected === this ? "red" : "blue"
MouseArea {
anchors.fill: parent
onClicked: manager.selected = parent
}
}
// main.qml
Window {
id: manager
visible: true
width: 600
height: 300
property Item selected: null
Row {
spacing: 2
Repeater {
model: 10
delegate: Rect {}
}
}
}
As the following example shows, you can directly access objects by id as long as they can be found down the object tree. The same applies to properties, however while the id will work for any object down the tree, properties will only work if they are declared in the root object of the particular qml file.
The following code works and shows my items correctly, but I get the warning
qrc:/TableDelegate.qml:24: ReferenceError: name is not defined
I think it is because the ListView tries to access the model when it is empty and can not reference the item properties. I assume I am not doing to it correctly but I do not know how to do it better.
So my question is: how to get rid of the warning by doing it the right way?
TableDelegate.qml:
import QtQuick 2.0
import QtQuick.Layouts 1.1
Item {
property color bgcolor: 'transparent'
property alias box: rowBox
height: 40
width: parent.width
Rectangle {
id: rowBox
anchors.fill: parent
color: bgcolor
RowLayout {
anchors.fill: parent
Rectangle {
id: tableNameColumn
color: 'transparent'
Layout.fillHeight: true
Layout.fillWidth: true
Text {
anchors.centerIn: parent
color: textcolor
text: name // <--- here is `name`
}
}
// More Columns ...
}
}
MouseArea {
anchors.fill: parent
onClicked: {
view.currentIndex = index
}
}
}
And I use it like this
TableView.qml:
// ...
ListModel {
id: model
}
ListView {
id: view
model: model
anchors.fill: parent
highlight: delegate_highlighted
highlightFollowsCurrentItem: true
delegate: delegate
}
Component {
id: delegate
TableDelegate {
bgcolor: 'transparent';
}
}
Component {
id: delegate_highlighted
TableDelegate {
bgcolor: 'lightsteelblue'
box.border.color: 'black'
box.radius: 3
}
}
// ...
You use a TableDelegate for the highlight. That is wrong.
The ListView creates 1 instance of the highlight item, that will be drawn as a background for the currently selected item, It may also move between items as transition when the current item changes. It should only be a rectangle or whatever you want to use.
In your example, the highlight item is a full delegate, that wants to access model data, which it cannot.
I'm new to Qt Quck and Qt5/PyQt, and now I've faced a strange problem. I'm trying to find an object with objectName "test" in the below QML definition like this:
self.rootObject().findChild(QObject, "test")
But the call returns None. However, if I move the objectName: "test" property to the parent Tab element, then it's found successfully. It's only not found whem inside the child Item. Similarly, addChannel, modifyChannel and removeChannel objects are also not found by findChild().
import QtQuick 2.0
import QtQuick.Layouts 1.1
import QtQuick.Controls 1.1
import "TouchStyles"
Item {
ListModel { }
TouchButtonFlatStyle { id: touchButtonFlat }
TouchTabViewStyle { id: touchTabView }
Rectangle {
width: 480
height: 230
TabView {
currentIndex: 0
tabPosition: 1
anchors.fill: parent
style: touchTabView
Tab {
title: "Play"
Item {
anchors.fill: parent
PianoKeyboard { anchors.centerIn: parent }
}
}
Tab {
title: "Channels"
Item {
objectName: "test"
ListView {
anchors.fill: parent
model: listModel
delegate: Channel {}
}
BorderImage {
border.bottom: 8
anchors.bottom: parent.bottom
source: "images/toolbar.png"
width: parent.width
height: 50
RowLayout {
anchors.verticalCenter: parent.verticalCenter
anchors.horizontalCenter: parent.horizontalCenter
Button { text: "Add"; objectName: "addChannel" }
Button { text: "Modify"; objectName: "modifyChannel" }
Button { text: "Remove"; objectName: "removeChannel" }
}
}
}
}
}
}
}
What am I doing wrong? The Qt documentation says that the search is performed recursively. Why doesn't it traverse the entire object tree?
The problem is related to the fact that tabs are "instantiated" only on demand. The first tab is always instantiated, so if you put the objectName there it will be found.
It will be found in the second tab only if you instantiate the second tab (select it). Similarly, using findChild on the TabView probably instantiates each tab (since it looking for them), so after that a findChild works even if second tab was not selected.
Conclusion: instantiate all tabs first (doing a findChild on the TabView is one way but may be a hack), then do the findChild for the item.
I have QtQuick 1.0
I use the following code:
Rectangle {
Component {
id: appDelegate
MouseArea{
id:myMouseArea
hoverEnabled: true
onClicked:{
onClicked: load.source = page;
}
}
Loader {
id: load
}
}
GridView {
id: view
// I am unable to access myMouseArea here.
highlight: myMouseArea.containsMouse ? appHighlight : !appHighlight
delegate: appDelegate
}
}
It gives me the following error:
ReferenceError: Can't find variable: myMouseArea
/usr/lib/i386-linux-gnu/qt4/bin/qmlviewer exited with code 0
I don't know if the details I provided are sufficient, please let me know if theres anything else I am missing.
I am using this code as an example:
http://docs.knobbits.org/qt4/declarative-modelviews-gridview-qml-gridview-example-gridview-example-qml.html
You cannot access myMouseArea because it's created inside delegate context. You cannot access delegate other then currentItem. But you can freely access view inside the context of delegate, to set currentIndex to attached property index.
This is a corrected code:
Rectangle {
width: 360
height: 360
Component { // It must be a component, if we want use it as delegate
id: appDelegate
// its not possible to have more than one element inside component
Rectangle
{
// need to set size of item, anchors wont work here
// could use view.cellWidth and view.cellHeight to keep it DRY
width: 96
height: 66
color: "green" // color only to see the place of MouseArea
MouseArea {
id:myMouseArea
anchors.fill: parent // this setup the size to whole rectangle
// it this item have the size 0,0 it will simple do not work
hoverEnabled: true
onEntered: {
// we know the mouse is inside this region
// setting this value will show the highlight rectangle
view.currentIndex = index;
}
onClicked:{
onClicked: load.source = page;
}
}
Loader {
// this is not needed but it's wise to not keep zero size
anchors.fill: parent
id: load
}
}
}
GridView {
id: view
// the size of GridView must be set,
// as otherwise no delegate will not show
anchors.fill: parent
anchors.margins: 5
cellWidth: 100
cellHeight: 70
// Rectangle will act as a border.
// Size and position is set by GridView
// to the size and position of currentItem.
// This is no a item, this makes a Component
// as highlight property needs one.
// You can create a Component like appDelegate.
highlight : Rectangle {
border.width: 2
border.color: "blue"
}
// some ListModel to setup the page variable inside delegate context
model: ListModel {
ListElement { page: "test1.qml"; }
ListElement { page: "test2.qml"; }
ListElement { page: "test3.qml"; }
}
delegate: appDelegate
}
}
I have a Widget as QML component in Qt Quick application which is to be used in various screens to display contents.
How can I use this particular QML component to adjust according to the items in it.
If it's a generic Item you can't: you have to manually set the container's size to fit its content.
The only QML components that fits their content are the Row, Column and Grid elements.
coming in way late, but if you want to have an update-able component you can set the model for the component to any list model like:
Component{
id:comp1
model:model1
}
ListModel {
id: model1
ListElement{
name:"a"
}
ListElement{
name: "b"
}
}
Component {
id: fruitDelegate
Row {
spacing: 10
Text { text: name }
}
}
ListView {
id:listView1
anchors.fill: parent
model: fruitModel
delegate: fruitDelegate
contentWidth: Screen.width
}
then you can update the listview at will
TextInput{
id: text_input1
width:parent.width * 0.80
text:"waddup?"
}
Button {
id: button2
anchors.left: text_input1.right
text: qsTr("Send")
onClicked: {
listView1.model.append( {name: text_input1.text, colorCode:"Red" });
/*text_input1.text = ""*/
}
}