Qt 使用调色板更改 QWidget 的背景颜色不起作用

Question

I want to change the background color in a custom subclass of QWidget. Here is the code:

WorldView::WorldView(QWidget *parent) : QWidget(parent)
{
    QPalette p(palette());
    p.setColor(QPalette::Background, Qt::black);
    setAutoFillBackground(true);
    setPalette(p);
}

But it doesn't work as expected. The background color remains unchanged.

I don't know why.

Answer 1

As you can read in the documentation , QPalette::Background is obsolete. Use QPalette::Window instead. Note that some widgets use some other role for the background. See the QPalette::ColorRole documentation

Also:

Warning: Some styles do not use the palette for all drawing, for instance, if they make use of native theme engines. This is the case for both the Windows XP, Windows Vista, and the OS X styles.

In this case I suggest to use style sheets. See Qt Style Sheets Reference

However, if WorldView is a custom widget, with your custom paintEvent , it's up to you to draw the background

Answer 2

Use QPalette::Base instead of QPalette::Background

 QPalette p(palette());
 p.setColor(QPalette::Base, Qt::lightGray);
 setPalette(p);

For some reason custom widget uses QPalette::Base for filling backgound

Answer 3

setStyleSheet('background-color:black;')

Answer 4

If the palette color doesnt work then it can have four reasons you should check

• you have set the colors from style sheets which i don't recommend at all or maybe you have set the parents stylesheet

• your color role in the palette doesnt match

• make sure the palette is set for widget and i dont recommend to set palette for every widget unless you really wanted to, you should set the palette for your application

• or maybe your window manager is forcing colors and palettes dont work at all

Thats all i got in my mind, if you know more, please edit this answere and add it to items