CODEWITHSUNDEEP
javascriptmathqml
rib3ye
rib3ye

Reputation: 2923

Basic Javascript/math in QML... why doesn't it work?

I'm pretty new to QML. According to the QML documentation at http://doc.qt.nokia.com/4.7-snapshot/qdeclarativescope.html, the Text object should show 15, but instead it only outputs 5. Can anyone help me out?

Text {
    id: counter
    x: 300;
    y: 300;
    property int a: 5;
    function randNumber(a){
        var a = a+10;
        return a;
    }
    text: a;
}

Upvotes: 1

Views: 1367

Answers (3)

RajaRaviVarma
RajaRaviVarma

Reputation: 2742

Neither pass it as an argument to the function nor create a new variable in the randNumber function using var. Simply use a. It should be availble in the function, since the function in inside the Text QML Component.

This is not working since you are not calling the function anywhere in your program. I assume that you want to call it on the start-up(technically when the Text component is loaded). So you can call it on the Component.onCompleted function.

Text {
    id: counter
    anchors.centerIn: parent
    property int a: 5;
    function randNumber(){
        a = a+10;
        return a;
    }
    text: a;
    Component.onCompleted: randNumber();
}

Look into this documentation for more examples.

Upvotes: 0

sepp2k
sepp2k

Reputation: 370132

You're never actually calling your randNumber function, so it will have no effect. If you want to set text to the result of randNumber(a), you should be doing text: randNumber(a). Or without defining a function:

text : {
    var a = a+10;
    return a;
}

If you remove the var, the a property will also be set to 15 (with the above code only text would be set to 15 and a would remain 5).

Upvotes: 1

Jonathan M
Jonathan M

Reputation: 17451

The a in your function is local to the function because you prefaced it with var. Instead, make it:

    function randNumber(a){
        a = a+10;
        return a;
    }

Upvotes: 2

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