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
        }
    }
}