How to expose multiple X and Y data to QML for charts

Praveen.Illa

Hi Team,
I am new to Qt and am struggling to implement a below requirement. Can anyone in the group suggest me how to implement

I have a requirement of plotting a graph in QML. For this, I need to send the list of X and Y- data from Qt -C++ (via list or QMap) to QML for plotting.
The X-axis is unsigned long int and Y-axis is double.
How can I send the list data in the format (X, Y), to the QML.
Also, i have seen in some of the forums suggesting to use QVariantList or QVariantMap. But, am not sure how to use these data types

GabrielRR

Hello, maybe something like this should help you using QMap
C++ type that maybe could help you:

class myCustomMap: public QObject
{
   Q_OBJECT
public :
   myCustomMap();

   Q_INVOKABLE int getX(int x) const
   {
        return _myMap.contains(x) ? _someMap[x] : 0;
   }

private:
    const static QMap<int, int> _myMap;  // Map```
}

I think with this you got the idea on how to proceed, you just need to create your QMap to accept something like:

struct Data{
    int x = 0;
    int y = 0;
};

QMultiMap<int, Data> map;
Data data;

data.x = 1;
data.y = 2;
map.insert(1, data);

eyllanesc

@Praveen-Illa See this example: https://stackoverflow.com/questions/48687705/how-to-use-the-vxymodelmapper-with-qstandarditemmodel/48688921#48688921

Praveen.Illa

@eyllanesc - Thank you for your support. I am able to plot the graphs in QML