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.
Related
I have a QWidget which should take place over the central widget of my application which is a VideoWidget for playing video. The problem is that I can't set background of the QWidget to be transparent.
Use a StyleSheet (you can do that in code with setStylesheet or in the ui file : RMB on the widget you want "Change stylesheet" or even in the properties tab)
for instance
"background-color: rgba(255, 255, 0, 50);"
gives a yellow transparant look:(example of a button used on top of another button)
With stylesheets you can control the look of a complete program or just the specific widgets you want. More info in the style sheet reference
You could make the full Widget invisible:
QWidget::setHidden(true);
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.
In my app, i have a section that is top widget, the color of the top widget is gray, and i've been put severl widget on top widget, like QComboBox, QLineEdit and 2 QButton, but i have a problem when i right click on QLineEdit as you seen in below picture, the color of default context of window is gray, or when i open the QComboBox the color of background is gray. I'll set the background color of two these widget to white but doesn't work. So, how can i fix this?
Sample for better understand:
http://0000.4.img98.net/out.php/i52512_problem.png
Please help me
The style sheet propagates to all the child widgets, so you have to limit their range by using the right selectors. Since the context menu is a child of the QLineEdit it is also affected.
// What you have probably done:
myLineEdit->setStyleSheet("background-color: gray");
// What you should have done:
myLineEdit->setStyleSheet("QLineEdit { background-color: gray }");
// What you should do if there might be child widgets of the same type
// but for which you don't want the style to apply:
myLineEdit->setObjectName("myLineEdit");
myLineEdit->setStyleSheet("QLineEdit#myLineEdit { background-color: gray }");
See "The Style Sheet Syntax - Selector Types" for details.
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.