如何更改 PyQt5 中的滚动条箭头键？

Question

Using the following code to set the style for vertical Qscrollbar. It gives the appearance/result as attached photo. I want to change the up and down arrow from Square to the actual up arrow ( triangle) on top and the down arrow at the bottom(inverse triangle). How to obtain it?

   QScrollBar:vertical {
   background: rgb(220,220,220);
   width: 15px;
   margin: 22px 0 22px 0; }

   QScrollBar::handle:vertical {
   background: rgb(169,169,169);
   min-height: 10px; }
   
   QScrollBar::add-line:vertical {
   border: 0px solid grey;
   background: rgb(220,220,220);
   height: 20px;
   subcontrol-position: bottom;
   subcontrol-origin: margin; }

   QScrollBar::sub-line:vertical {
   border: 0px solid red;
   background: rgb(220,220,220);
   height: 20px;
   subcontrol-position: top;
   subcontrol-origin: margin;}
   
   QScrollBar::up-arrow:vertical, QScrollBar::down-arrow:vertical {
   border: 0px solid red;
   display: ᐃ
   width: 5px;
   height: 5px;
   background:black;}

Answer 1

You must use images to get arrow icons.

QScrollBar::right-arrow,
QScrollBar::left-arrow,
QScrollBar::up-arrow,
QScrollBar::down-arrow {
    width: 12px;
    height: 12px;
    background: black;
}

QScrollBar::right-arrow {
    image: url("://icons/theme-dark/caret_right.svg");
}
QScrollBar::left-arrow {
    image: url("://icons/theme-dark/caret_left.svg");
}
QScrollBar::up-arrow {
    image: url("://icons/theme-dark/caret_up.svg");
}
QScrollBar::down-arrow {
    image: url("://icons/theme-dark/caret_down.svg");
}

The images can be anything, in any format Qt supports (png, jpg, gif, etc). The above URL syntax uses images embedded in an included Qt resource file (but they could also be file:// URLs, or actual network requests (http/s, etc)).

You do not need the :vertical or :horizontal qualifiers (the elements are already "directional"). Also the way you're using display is incorrect, and besides Qt doesn't support it anyway (nor content which is I think what you meant).

Answer 2

In addition to manually supplying images for arrows, you could try different window styles. If you use Designer for your app, you can preview styles from Form...Preview In -> Style. It's hard to find in the docs, but if you look here , there are some styles.

In your code you do it at the app level:

if __name__ == '__main__':
    app = QApplication(sys.argv)
    app.setStyle(QStyleFactory.create('fusion'))