trying to create list (docs seem in error)

[mzimmers]

Hi all -

I'm trying to create a list, but am getting errors. I tried the code in the pic below -- this came straight from the docs:

Here's how I'm trying to use it - I may have my own errors in how I'm trying to use color:

property list<color> rectColors: [Qt.red, Qt.green, Qt.blue, Qt.yellow, Qt.orange]
Repeater {
    id: rects
    model: rectColors
    Rectangle {
        width: mainWindow.width 
        height: 100
        color: rectColors[index]
    }
}

Any ideas on what's going on here? Thanks...

[GrecKo]

@mzimmers What @JoeCFD said is only true for Qt 5. In Qt 6 in can also hold basic value types as mentioned by the doc you linked.

Qt Creator is bit confused in its linting but the code actually runs.

There is a problem in your code though. Qt.red and its friends are not actual colors but enums, you can't cast them to color.

You could use a QColor from C++, Qt.rgba(), a SVG color name or hex color code:
property list<color> rectColors: ["red", "green", "blue", "yellow", "orange"]

[JoeCFD]

@mzimmers https://stackoverflow.com/questions/26733011/how-to-declare-list-property-in-qml

[mzimmers]

@JoeCFD:

1. so, the doc is wrong?
2. according to the link you provided, lists can only store QML objects. That would seem to imply that I can't create a list of colors...true?

[JoeCFD]

@mzimmers
https://doc.qt.io/qt-5/qml-list.html
A list can only store QML objects, and cannot contain any basic type values.
(To store basic types within a list, use the var type instead.)

[mzimmers]

@JoeCFD OK, thanks...it was worth a try.

[GrecKo]

@mzimmers What @JoeCFD said is only true for Qt 5. In Qt 6 in can also hold basic value types as mentioned by the doc you linked.

Qt Creator is bit confused in its linting but the code actually runs.

There is a problem in your code though. Qt.red and its friends are not actual colors but enums, you can't cast them to color.

You could use a QColor from C++, Qt.rgba(), a SVG color name or hex color code:
property list<color> rectColors: ["red", "green", "blue", "yellow", "orange"]

[JKSH]

@JoeCFD said in trying to create list (docs seem in error):

A list can only store QML objects, and cannot contain any basic type values.

Not true since Qt 6.4. See https://doc.qt.io/qt-6/qml-list.html#using-the-list-type

(To store basic types within a list, use the var type instead.)

Using var prevents your QML code from getting compiled to C++ (see https://www.qt.io/blog/the-new-qtquick-compiler-technology ). Always prefer the specific type where possible.

@mzimmers said in trying to create list (docs seem in error):

1. so, the doc is wrong?

No, Qt Creator is wrong: https://bugreports.qt.io/browse/QTCREATORBUG-28238 It will be fixed in Qt Creator 10.0 (the beta is currently available from the online installer)

Your code will run fine with Qt 6.4 and newer.

2. according to the link you provided, lists can only store QML objects. That would seem to imply that I can't create a list of colors...true?

False 😊 But @GrecKo is right: Use "red" instead of Qt.red

[JoeCFD]

@JKSH You two guys are right. a list in Qt6 is different.

[mzimmers]

Thanks for the clarification on this. I downloaded Creator 10 and as @JKSH said, the error disappeared. Here's the working code:

Column {
    Repeater {
        id: repeater
        property list<color> rectColors: ["red", "green", "blue", "yellow", "orange"]
        model: rectColors
        Rectangle {
            width: mainWindow.width
            height: 100
            color: repeater.rectColors[index]
        }
    }
}

Seems to work fine. Now I can ask my real question (in another topic). Thanks again.

[GrecKo]

@mzimmers

You are not using Repeater the intended way. You are not supposed to acces the raw model from the delegates, let the Repeater provide you the data.

Change

color: repeater.rectColors[index]

with

color: modelData

[mzimmers]

@GrecKo noted; thanks.