How to create a childwidget with other color as parent

Lukas02

I want to make a black mainwindow with a yello label in the window, (not in designer-mode).
I tried this:

    mainWindow.setFixedSize(1100, 900);
    mainWindow.setPalette(QPalette(Qt::black));

    QLabel* brett = new QLabel(&mainWindow);
    brett->setFixedSize(800, 800);
    brett->move(10, 10);

    brett->setPalette(QPalette(QPalette::Base, Qt::yellow));

    brett->show();
    mainWindow.show();

the mainwindow gets black, correctly, but the label is also black. (because its a child of the mainwindow

I tried this:

mainWindow.setFixedSize(1100, 900);
    mainWindow.setPalette(QPalette(Qt::black));

    QLabel* brett = new QLabel();
    brett->setFixedSize(800, 800);
    brett->move(10, 10);

    brett->setPalette(QPalette(QPalette::Base, Qt::yellow));

    brett->show();
    mainWindow.show();

now the label is yello, but its not a child of the mainwindow more, and so its showed in a new window.

How to change the Color of one Label, without changing the color of the parent?

raven-worx

@Lukas02
use "QPalette::Background" for the child widget

Pl45m4

@Lukas02

You can use a stylesheet for your mainWindow to make the background black and another stylesheet to make your label yellow.

setStylesheet("QMainWindow#myWindow { background: black; }");
brett->setStylesheet("QLabel#brett { color: yellow; }");

brett->move(10, 10);

You usually want to put your label in a layout.

Lukas02

@raven-worx
i already tried this. But thx

QLabel* brett = new QLabel(&mainWindow);
    brett->setFixedSize(800, 800);
    brett->move(10, 10);

    brett->setPalette(QPalette(QPalette::Background, Qt::yellow));

the same problem

Lukas02

@Pl45m4
The StyleShet - version fixed the problem. Thak you.
But I dont understand my mistake in my first version.

Pl45m4

@Lukas02 said in How to create a childwidget with other color as parent:

But I dont understand my mistake in my first version.

QWidget propagates explicit palette roles from parent to child. If you assign a brush or color to a specific role on a palette and assign that palette to a widget, that role will propagate to all the widget's children, overriding any system defaults for that role. Note that palettes by default don't propagate to windows (see isWindow()) unless the Qt::WA_WindowPropagation attribute is enabled.

(from: https://doc.qt.io/qt-5/qwidget.html#palette-prop)