Category Archives: QML

“Cannot anchor to a null item” waring in QML

The following QML code

    id: call

    //margins should bound but not assigned
    anchors.topMargin: root.above ? undefined : yMargin
    anchors.bottomMargin: root.above ? yMargin : undefined


produced “Cannot anchor to a null item” warning and worked incorrectly.

I tried to replace it with AnchorChanges and PropertyChanges:


QML Application Style

There was qtquickcontrols2.conf in the root directory of my app sources with the following content:

; This file can be edited to change the style of the application
; See Styling Qt Quick Controls 2 in the documentation for details:




My experimentation with QML Repeater

I was able to define a Repeater that displays cryptocurrency market orders:


An example of real-time TableView in QML

Looks like CheckBox-es respond to clicks and work correctly even if they are in a TableView that is updated once a second:


Using QML_ELEMENT with CMake

There is an example of using QML_ELEMENT in qt5\qtdeclarative\examples\quick\scenegraph\openglunderqml and qt_add_qml_module in CMake:

    URI OpenGLUnderQML
    VERSION 1.0
    QML_FILES main.qml
    RESOURCE_PREFIX /scenegraph/openglunderqml

In QML it imports the module:

import OpenGLUnderQML 1.0

Dragging a link from a browser to a QML app

When a link is dragged from a browser on Window 10 platform it contains the page title, but they did not make it accessible in QML:

import QtQuick 2.15
import QtQuick.Controls 2.15

ApplicationWindow {
    visible: true
    width: 640
    height: 480
    title: qsTr("Scroll")
    id: root

    DropArea {
        id: dropArea;
        anchors.fill: parent
        onEntered: {
            root.color = "gray";
            drag.accept (Qt.LinkAction);

Assignment a property of type function in QML

It is possible to do this in QML:

    property var refreshChart: function () {}

        refreshChart = function ()

Multiple views with OsgQtQuick

I wrote a sample application using OsgQtQuick that shows the Earth in two views:

with the following QML, that I copied from OsgQtQuick samples:


Qt Quick Controls 2 has TableView but without the header yet

QT 5.13 supports SplitView and TableView but without TableHeader yet. Probably TableHeader can be implemented with the overlays. And there is an interesting example of implementation of table header with the source code.

The information provided below is outdated.

Qt Quick Controls 2 does not support TableView and looks like they are not going to support it, some notable missing features from Qt Quick Controls 1 also are Action, SplitView and TreeView, so the following QML code would not work:

TableView {

    TableViewColumn {
        role: "time"
        title: qsTr("date/time:")
        width: parent.width - 30

    TableViewColumn {
        role: "score"
        title: qsTr("result:")
        width: 30

    model: boardModel.list

    ScrollIndicator.vertical: ScrollIndicator { }

But there is a solution with ListView, so there can be something like this:


QML DropShadow is very slow

QML DropShadow is an interesting effect that acts in a very simple way. It works fine in my application and produces the following result:

QML DropShadow is very slow

The only disadvantage of DropShadow effect is that is slows down my application from 60 FPS to 30 FPS on Android Phone. The following code demonstrates how I use it with StackView: