CODEWITHSUNDEEP
qmlblackberry-10blackberry-cascades
donturner
donturner

Reputation: 19146

Why doesn't my QML property update when it is bound to Slider.value property?

I have a QML document with an int property, a Slider and a Button in it. I want x to always have the same value as Slider.value. Here's my QML:

Page {
    property int x: 1

    content: Container {
        Slider {
            fromValue: 1
            toValue: 500
            value: x
            onValueChanged: {
                console.log("Slider value is: "+value);
                console.log("x value: "+x);  
            }
        }
        Button {
            text: "Increment x"
            onClicked: {
                x=x+10;
            }
        }
    }
}

When I press the Button the slider value is updated AND x is updated. But when I move the slider, the value of x is not updated. Why doesn't the value of x change when I move the slider?

Upvotes: 2

Views: 2887

Answers (3)

Dickson
Dickson

Reputation: 1261

Because your x is not bound to the Slider.value. When you bind Slider.value to x, if x changes, Slider.value will also change BUT if Slider.value changes (when you slide it), the x value will not be changed.

To solve this, you can use the alias type

property alias x: slider.value // assume the Slider has a id of "slider"

Upvotes: 4

Nishant Shah
Nishant Shah

Reputation: 1586

Use onImmediateValueChanged signal instead of onValueChanged

...
onImmediateValueChanged: {
    console.log("Slider value is: "+value);
    console.log("x value: "+x);  
}
...

Upvotes: 1

bslack
bslack

Reputation: 21

Try this:

Page {
property int x: **sliderID.value**

content: Container {
    Slider {
        **id: sliderID**
        fromValue: 1
        toValue: 500
        value: x
        onValueChanged: {
            console.log("Slider value is: "+value);
            console.log("x value: "+x);  
        }
    }
    Button {
        text: "Increment x"
        onClicked: {
            x=x+10;
        }
    }
}

}

I established a two-way binding.

Upvotes: 2

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