Error: Qt.createQmlObject(): failed to create object: Non-existent attached object

[Kyeiv]

I have a QVariantMap which i use to create children of GridLayout

my code:

import QtUtils 1.0
import QtQuick 2.5
import QtQuick.Controls 1.4
import QtQuick.Layouts 1.2
Item
{
    Connections
    {
        target: model
        onModelChanged: updateSummaryList()
    }
    function updateSummaryList() {
        for(var i = summaryGrid.children.length; i > 0 ; i--) {
            console.log("destroying: " + i)
            summaryGrid.children[i-1].destroy()
        }

        try
        {
            for (var prop in model.map) {
                var labelText = Qt.createQmlObject('import QtQuick 2.5;Text { text: "first text:"; color: "white"; horizontalAlignment: Text.AlignRight; Layout.alignment: Qt.AlignRight; }',
                    summaryGrid,
                    prop+"label");
                
                var valueText = Qt.createQmlObject('
                    import QtQuick 2.5;\
                    Text { text: "text"; color: "white";}',
                    summaryGrid,
                    prop+"value");
            }

        }
        catch (error)
        {
            console.error(error);
        }
    }
                GridLayout {
                            id: summaryGrid
                            Component.onCompleted: updateSummaryList()
                            columns: 2
                        }
}

When i run this code i get:

Error: Qt.createQmlObject(): failed to create object: field1label:1:102: Non-existent attached object

What may be the reason?

[jeremy_k]

A ListView appears to be a better match than the more complicated GridLayout and Repeater.

ListView {
    delegate: Item {
        width: ListView.view.width
        height: childrenRect.height
        Text {
            anchors.right: parent.horizontalCenter
            text: modelData.firstPart + ":"
        }
        Text {
            anchors.left: parent.horizontalCenter
            text: modelData.secondPart
        }
    }
}

[sierdzio]

The only attached object is Layout so it's probably the reason to fail: QML engine does not see the GridLayout when creating your object.

Rather than fixing this, though, I'd recommend using a completely different approach:

• use Repeater in your GridLayout to create the items you need
• pass the model you have to Reapeater so that it updates automatically (there will be no more any need for Connections component)
• do not create components in QML dynamically

This should greatly simplify the logic.

[Kyeiv]

@sierdzio said in Error: Qt.createQmlObject(): failed to create object: Non-existent attached object:

• use Repeater in your GridLayout to create the items you need

But Repeater supports only one Component as delegate. I want it to fill 2 columns of GridLayout with 2 Text delegates.

Static grid that i am trying to make dynamic:

GridLayout {
                            id: grid
                            columns: 2

                            Text { 
                                text: "first text:"; 
                                color: "white"; 
                                horizontalAlignment: Text.AlignRight
                                Layout.alignment: Qt.AlignRight
                                }
                            Text { text: "text"; color: "white"}
                            Text { 
                                text: "second text:"; 
                                color: "white"; 
                                horizontalAlignment: Text.AlignRight
                                Layout.alignment: Qt.AlignRight
                                }
                            Text { text: "text text"; color: "white"}
                            Text { 
                                text: "the third text:"; 
                                color: "white"; 
                                horizontalAlignment: Text.AlignRight
                                Layout.alignment: Qt.AlignRight
                                }
                            Text { text: "text text text"; color: "white"}
                        }

Its output:

                        first text: text
                       second text: text text
                    the third text: text text text

[jeremy_k]

@Kyeiv said in Error: Qt.createQmlObject(): failed to create object: Non-existent attached object:

@sierdzio said in Error: Qt.createQmlObject(): failed to create object: Non-existent attached object:

• use Repeater in your GridLayout to create the items you need

But Repeater supports only one Component as delegate. I want it to fill 2 columns of GridLayout with 2 Text delegates.

Wrap the 2 delegates in a single component and use the index property to decide which to use for each cell.

[Kyeiv]

@jeremy_k I am not sure how to achieve it, can you provide some sample code?

[jeremy_k]

GridLayout {
    columns: 2
    Repeater {
        model: 10
        delegate: Text {
                text: index % 2 == 0 ? "text " + index : "text" * index
        }
    }
}

For more complicated or external delegates, substitute DelegateChooser or Loader for the Text item.

[Kyeiv]

@jeremy_k But my model is in format of QVariantMap, for example:

"key" : { "label": "first text"; "value": "text" }
"key2" : { "label": "second text"; "value": "text text" }

so i cannot see how to take advantage of indexes in here.

[jeremy_k]

@Kyeiv Use a model.

Edit: QVariantMap might be directly usable as a model for a repeater as well. If so, index is available, as is modelData.

[Kyeiv]

@jeremy_k yes but still if so, i cannot take advantage of the index property when i use one object, let's say of index 1 to fill 2 Texts

i need something like:

GridLayout {
    columns: 2
    Repeater {
        model: model.map
        delegate: Text {
                text: modelData.label
                horizontalAlignment: Text.AlignRight
                Layout.alignment: Qt.AlignRight
        }
       Text {
                text: modelData.value
        }
    }
}

[jeremy_k]

@Kyeiv You might be better off starting from a sketch or a description the use case. It looks like this is implementing the hard way, perhaps porting from a toolkit with a different structure.

[Kyeiv]

@jeremy_k
what i have: a map of objects which have 2 attributes - label and value.
what i want to achieve: the formatted list of them in form of:

                        first label text: value text
                       second label text: value text
                    the third label text: its value text

so its centered, the " : " in the middle.

[fcarney]

@Kyeiv said in Error: Qt.createQmlObject(): failed to create object: Non-existent attached object:

GridLayout {
columns: 2
Repeater {
model: model.map
delegate: Text {
text: modelData.label
horizontalAlignment: Text.AlignRight
Layout.alignment: Qt.AlignRight
}
Text {
text: modelData.value
}
}
}

Then just put them in one delegate item:

GridLayout {
    columns: 2
    Repeater {
        model: model.map
        delegate: Column {
        Text {
                text: modelData.label
                horizontalAlignment: Text.AlignRight
                Layout.alignment: Qt.AlignRight
        }
       Text {
                text: modelData.value
        }
        }
    }
}

[jeremy_k]

A ListView appears to be a better match than the more complicated GridLayout and Repeater.

ListView {
    delegate: Item {
        width: ListView.view.width
        height: childrenRect.height
        Text {
            anchors.right: parent.horizontalCenter
            text: modelData.firstPart + ":"
        }
        Text {
            anchors.left: parent.horizontalCenter
            text: modelData.secondPart
        }
    }
}