Qchart formatLabel QML

Chobin

Hello everybody,

I'm developing a linear chart using qml with qt creator, and I'd like to append a character to every Y axis label. For example I want append "°C" to the number 15: the final resul should be 15°C. I tried to use the following QML code, but the resul is 15?C.

ValueAxis {
min: 0
max: 100
labelFormat: "%d%1".arg("°C)
}

Does someone help me?
Many thanks in advance.

Best Regards,
Chobin

Diracsbracket

@Chobin
As the documentation states, this is not supported by the ValueAxis of the QtCharts module.
https://doc.qt.io/qt-5/qml-qtcharts-valueaxis.html#labelFormat-prop

Whenever you try to use a second format specifier in .arg(), you will get a message like:

QString::arg: Argument missing

This is unlike the labelFormat property in the QtDataVisualization module, see for example
https://doc.qt.io/qt-5.11/qtdatavisualization-qmlbars-example.html, where the following does work:

labelFormat: "%d \u00B0C"

In your case, an annoying workaround would be to use a CategoryAxis instead.

e.g.

            axisX: CategoryAxis {
                min: 0
                max: 4
                labelsPosition: CategoryAxis.AxisLabelsPositionOnValue
                CategoryRange {
                    label: "1 \u00B0C"
                    endValue: 1
                }
                CategoryRange {
                    label: "2 \u00B0C"
                    endValue: 2
                }
                CategoryRange {
                    label: "3 \u00B0C"
                    endValue: 3
                }
                CategoryRange {
                    label: "4 \u00B0C"
                    endValue: 4
                }
            }

To be practical, you may need to create this one dynamically instead...