CODEWITHSUNDEEP
pythonqtqmlqtquick2pyqt5
Willbot
Willbot

Reputation: 83

modelData is not defined for QML ComboBox with more than one role in QAbstractListModel

This appears to be the same (unanswered) issue as here: QML Combobox reports ReferenceError: modelData is not defined . The closest (closed) bug in the QT database I can find is: https://bugreports.qt.io/browse/QTBUG-31135 so I'm not sure that this is the same issue. I'm running PyQt5 v5.5 and python 3.4.3.

I'm implementing a QAbstractListModel in PyQt5, and have distilled the code down to the issue at hand:

# ExampleModel.py

class ExampleModel(QAbstractListModel):

    def __init__(self, parent=None):
        super().__init__(parent)
        self.items = []

        for t in range(0,10):
            self.items.append({'text': t, 'myother': 'EXAMPLE'})

    def data(self, index, role):
        key = self.roleNames()[role]
        return self.items[index.row()][key.decode('utf-8')]

    def rowCount(self, parent=None):
        return len(self.items)

    def roleNames(self):
        return {Qt.UserRole + 1: b'text',
                Qt.UserRole + 2: b'myother'}

And the related QML:

# example.qml
...
ComboBox { // Displays blank entires + throws ReferenceError
    id: comboExample
    model: ExampleModel{}
    textRole: 'text'  # This was the missing line to make this work.
}

ListView {  // Works Correctly
    id: listExample
    model: ExampleModel{}
    delegate: Text {
        text: myname + " " + myother
    }
}
...

When I run this, the combo box has 10 blank entries, and the console error log shows:

[path]/ComboBox.qml:562: ReferenceError: modelData is not defined

(x 10)

Now, if I modify the roleNames() code in ExampleModel.py above to the following:

def roleNames(self):
    return {Qt.UserRole + 1: b'myname'}

the ComboBox works correctly.

Am I missing a key concept here? I don't want to implement my model twice (once for this ComboBox workaround.)

Edit

By adding Mitch's suggestion to example.qml above, this problem is fixed. The code has been updated accordingly.

Upvotes: 2

Views: 3027

Answers (1)

Mitch
Mitch

Reputation: 24416

You need to set textRole to the name of the role you want to display ("text", in your case).

The documentation could be a lot clearer about this, so I've created a bug report.

Upvotes: 3

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