How to push values to QML property variant two dimensional array - dynamically?

[TheIndependentAquarius]

This is what I have tried:

import QtQuick 2.0
 
Rectangle
{
    property variant twoDimTempArray: [[]]
    property variant oneDArray: [1,2,3]
 
    MouseArea
    {
        anchors.fill: parent
        onClicked:
        {
            twoDimTempArray.push (oneDArray)
 
            twoDimTempArray[0].push (oneDArray)
 
            twoDimTempArray[0][0] = oneDArray[0]
 
            console.log (twoDimTempArray)
        }
    }
}

import QtQuick 2.0

Rectangle
{
    property variant twoDimTempArray: [[]]
    property variant oneDArray: [1,2,3]

    MouseArea
    {
        anchors.fill: parent
        onClicked:
        {
            twoDimTempArray.push (oneDArray)

            twoDimTempArray[0].push (oneDArray)

            twoDimTempArray[0][0] = oneDArray[0]

            console.log (twoDimTempArray)
        }
    }
}

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They all results in

[]

[]

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.

How to push values in QML property variant two dimensional array?

[anda_skoa]

What exactly are you trying to do?

Cheers,
_

[TheIndependentAquarius]

I want to pass this 2 dimentional array from QML to C++ after filling some dynamically calculated values in it.

[anda_skoa]

Why don't you create and calculate in C++ directly?

It seems you are trying to solve a problem that doesn't exist in a properly designed program.

Can you give a real world example instead of an abstract explanation?

Cheers,
_

[TheIndependentAquarius]

Why don't you create and calculate in C++ directly?

This question does not make much sense to me.

I have a GUI designed in QML. User is supposed to fill in some values there.
I am supposed to calculate something from those values and then pass them to C++ so that they can be used
in an algorithm.

You think this kind of problem cannot exist in a properly designed program?

Anyways,

I have found a temporary solution as follows:

One way to add the values dynamically to a 1 dimensional QML variant is to fill a normal Javascript array and then assign it to the QML variant.

import QtQuick 2.0
 
Rectangle
{
    property variant oneDArray: []
    MouseArea
    {
        anchors.fill: parent
        onClicked:
        {
            var t = new Array (0)
            t.push(11)
            t.push(12)
 
            oneDArray = t
 
            console.log (oneDArray)
        }
    }
}

import QtQuick 2.0

Rectangle
{
    property variant oneDArray: []
    MouseArea
    {
        anchors.fill: parent
        onClicked:
        {
            var t = new Array (0)
            t.push(11)
            t.push(12)

            oneDArray = t

            console.log (oneDArray)
        }
    }
}

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Output:

Starting /home/.../documents/test/build-junk-Desktop_Qt_5_1_0_GCC_64bit-Debug/junk...
QML debugging is enabled. Only use this in a safe environment.
[11,12]
/home/.../documents/test/build-junk-Desktop_Qt_5_1_0_GCC_64bit-Debug/junk exited with code 0

Starting /home/.../documents/test/build-junk-Desktop_Qt_5_1_0_GCC_64bit-Debug/junk...
QML debugging is enabled. Only use this in a safe environment.
[11,12]
/home/.../documents/test/build-junk-Desktop_Qt_5_1_0_GCC_64bit-Debug/junk exited with code 0

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[anda_skoa]

This question does not make much sense to me.

The question if you can provide a real world example?

I have a GUI designed in QML. User is supposed to fill in some values there.

So far so goo.

I am supposed to calculate something from those values and then pass them to C++ so that they can be used
in an algorithm.

Why don't you simply pass the values from the UI?
What makes it necessary to do calculations in the UI?

You think this kind of problem cannot exist in a properly designed program?

No. But in a lot of cases strange requirements for QML side code are hints that the program does things in the UI context that would better be done in the application's non-UI parts.

One way to add the values dynamically to a 1 dimensional QML variant is to fill a normal Javascript array and then assign it to the QML variant.

Which also has the advantage of changing the value, meaning property bindings get updated.

Cheers,
_

[TheIndependentAquarius]

Why don't you simply pass the values from the UI?

I have several points on the UI. I want the user to select some points from them.
I need to calculate the distance between the points selected by the user.
This part can be done in C++ for sure,

but I still will have to `push` the points selected by the user in a `variant` and then pass the variant to C++.
Won't I?

[anda_skoa]

Depends on how you get these points in the first place.

For example if they originate in C++, e.g. as data accessed through a model, then selection could also be tracked there (state less UI).
Or the selection could be tracked in QML and passed to C++ when done.

But yes, if the values originate in QML then you'll need to pass them to C++.
Either using a C++ based property or a function call. The latter could take a list or each point individually.

Which is why I was asking for the actual use case really early.

It is usually better to find a solution to the actual problem and not to some abstract, academic one

Cheers,
_