I have a QDockWidget:
I would like to alert the user to certain events by setting the background color of the title bar.
I have achieved this by setting the style sheet for my DockWidget:
void DockWidget::setCriticalAlert()
{
setStyleSheet("QDockWidget { background-color:red; }");
}
The result is this:
The problem is that the background-color doesn't get applied when the QDockWidget is docked:
How can I get the background color to be applied when the QDockWidget is docked?
This is a bug in Qt.
Issue 10537
Quoting from the linked issue:
The problem is that in QDockWidget::paintEvent, there is a
isFloating() condition before drawing PE_FrameDockWidget. We cannot
jsut remove this condition as it would break the other style (that
does not whish to draw frame when the dockwidget is docked) We cannot
either use PE_Widget to draw the frame as then it goes over the
dockwidget's title The solution is maybe to introduce a new
PE_FrameDockWidgetDocked primitive element. Or some
SH_DockWidget_DrawDockedFrame stylehint to draw the frame in every
cases.
a valid workaround seems to be to set the stylesheet of the parent, and use the class-and-id selector. Forgive the python formatted code but the concept is the same - in this case, 'dock' is a QDockWidget which has been given an object name using setObjectName(), and its parent, the QMainWindow, is 'self':
self.setStyleSheet("QDockWidget#"+str(dock.objectName())+"::title {background-color:red}")
In PyQt5.5, this works at runtime, i.e., can be changed on the fly.
I find a solution like this:
Firstly put a frame behind all the widgets of dockwidget's center widget, as the background.
Then set stylesheet for the frame.
By this way, we could change the background color of dockwidget.
Or you can extend the dockwidget and overwrite the function
void QDockWidget::setWidget(QWidget *widget)
using private/qdockwidget_h. and add a frame as this widget's father.
Related
I have created a QPushButton in Qt without applying any style, so it inherits the style from Windows10, with this result:
Then I wanted to change temporary the color of the button, so I used:
pushButton->setStyleSheet("background-color: rgb(255,220,220)")
getting this result:
Already this result does not satisfy me because also the style is slightly different from the original one. Anyway the next step was that the button had to return to the "normal" style when pressed, so I added this command
pushButton->setStyleSheet("background-color: rgb(240,240,240)")
but the result is different from the starting button:
Can you please give me some advice to better manage the style?
Thanks
Actually when you set background-color alone to QPushButton, The background may not appear unless you set some value for border.
Look here for (List of Stylable Widgets: QPushButton)
http://doc.qt.io/qt-5/stylesheet-reference.html
I think in windows 10 for some reason, you are able to see something without even setting border.
But the recommended way is to set some border value.
So try setting border value as said below, and see if it addresses your requirement:
pushButton->setStyleSheet("background-color: rgb(255,220,220);border: none; ")
In the above said link you can find below information:
Warning: If you only set a background-color on a QPushButton, the background may not appear unless you set the border property to some value. This is because, by default, the QPushButton draws a native border which completely overlaps the background-color.
Here are some snippets you may find quite similar and helpful.
I had an Update button which I turned into red Cancel button. Once the update action is finished or cancel is pressed, I restored the original color and text.
// Global variables to save off button state
QPalette update_btn_palette_restore;
QString update_btn_text_restore;
....
// Update button is pressed.
// Save the palette and text.
update_btn_palette_restore = _ui->update_button->palette ();
update_btn_text_restore = _ui->update_button->text ();
// Change the color palette and text
QPalette p=palette();
p.setBrush(QPalette::Button,Qt::red);
_ui->update_button->setPalette(p);
_ui->update_button->setText ("Cancel");
....
// Handler for when either cancel is pressed or update has finished
if(! update_btn_text_restore.isEmpty ()) {
_ui->update_button->setText (update_btn_text_restore);
_ui->update_button->setPalette(update_btn_palette_restore);
}
I have a custom widget which inherits from QWidget and contains some labels in its layout. I would like to change the background color of the widget and the labels in the widget (this is, everything!) every time I put the mouse over it.
When using *:hover { background: red; } in my custom widget, I only get the contents red when moving the mouse over the labels, but not outside them, between labels, etc. I don't understand this behavior taking into account that I put the StyleSheet in the parent widget.
Any ideas? Many thanks,
You can set the parent's stylesheet which will cascade to children like this:
parent->setStyleSheet("* {background: red}");
For hovering only:
parent->setStyleSheet("*:hover {background: red}");
Check out https://qt-project.org/doc/qt-5.1/qtwidgets/stylesheet-syntax.html
Finally I solved the problem creating a QFrame inside the main QWidget and setting the StyleSheet of that QFrame.
I've a class that extends QWidget and contains a QLabel (lblBackground). I've overriden paintEvent function too.
I want to draw something on top of lblBackground however paintEvent method is called before the QLabel is drawn. Thus my custom drawings are overwritten.
Is there a way to change drawing order?
Painting the children on top of their parent is the common thing to do. That being said you could try one of the following options:
extend QLabel itself to paint whatever you want
try to set the Qt::WA_TranslucentBackground flag on the QLabel and having an alpha channel, so that the underlying parent (QWidget) would shine through
if you are only using the QLabel to paint some background, maybe you can get rid of it and paint the desired background first thing in the QWidget's paintEvent()?
If you want to use label as a background then just create your custom widget as a child of your label. May be split some window frame related tasks if any (to be implemented as a parent of the label) and drawing/controls/etc (to be child of the label).
Using Qt Creator, I have set a QWidget's background property to black. However, some parts of the QWidget, more specifically, between QFrames/QGroupBoxes are still in its system's default color.
Now, I thought that the QFrames and QGroupBoxes need to have its background property set to black too, but it did not work. I have also tried setting the border-color to black, but it does not work, since by default borders, margins are set to 0.
QWidget { background: black; }
Any advice on this issue?
EDIT
The QWidgets are placed in QMdiArea. However, if I make it a QWindow, it works. However, I want the QWidgets to be in the QMdiArea. Also, if I just show the QWidgets as it is, the spaces that I have mentioned above are transparent.
It sounds like you have some widgets within another widget, and are setting the contained widgets to be black, but then the space between them is not black. If that is the case, it is likely because you have a layout in the containing widget, which allocates space between each contained widget. The empty space between widgets will be drawn with the containing widget's background color.
Found out the solution. It seems that you need to set the background color at the QMdiSubWindow, not at QWidget. Don't know why, but it seems logical.
I've got a long horizontal QLabel displaying a png (the image shows a signal/time graph). Under that, I've got a QTableWidget. Both of these are in a QScrollArea because I want them to stay vertically aligned (the cells in the table correspond with the signal seen directly above them). I'm trying to add a handler to the QLabel such that the user can use the picture itself to scroll the scrollarea, rather than having to use the scrollbar. Is there a tried-and-tested way to do this? Directly setting the scrollarea's sliderPosition inside the QLabel's dragMoveEvent doesn't seem smart, because when the scrollarea scrolls it also leads to another dragMoveEvent on the (moving) QLabel.
I would suggest wrapping the combination (including the scroll area) in their own widget, and overriding the dragMoveEvent() on that widget. The dragMoveEvent() shouldn't be triggered when you change the scroll position if you are doing it this way, I wouldn't think, although I haven't actually tested it.