Hi and welcome to devnet,

First thing, please don't delete all that stuff in your destructors. Qt has a pattern that is based on parent widget (the parameter "this" in widget constructors) that take care of destructing all the children automatically when the parent is deleted: http://doc.qt.io/qt-5/objecttrees.html

Now regarding your problem, only one widget can have focus at the same time. For the focus part, you can use setFocusPolicy on your widgets, giving an enum that tells more about the behavior you expect.

For what I have experienced, playing with opacity and trying to give a modern look to a desktop software is kind of a pain. Long story short: there is no user friendly API to do so, or at least as user friendly as what QML provides. This is either because the widgets part is late compared to the QML one, or because "modern" has been associated with app, browsers, Internet, but not with desktop. Nonetheless, things might evolve in the future, since Qt developers have communicated about resuming the widgets development. This doesn't solve your problem, but could explain why you are having so much trouble trying to code an overlay that behaves with good focus policy, and using low level code such as QPalette that is always a sign you're doing something wrong, or at least not initially intended. Which could be fine, if you really know what you're doing, and you are aware that you'll have to deal with a lot of work to make your application look the same on every platform.

EDIT:
So I created a project with your code and here are some remarks:
1 Do not set a layout to your main window, just set the central widget with, well

setCentralWidget(widget)

2 qreal is an alias for double, so instead of qreal(100)/100 just write 1.0; same for qreal(50)/100, just write 0.5 and it will be perfectly fine.

3 No need to use "this->" you are coding in C++, not JAVA ;)

For your problem, I think I don't really get what you are expecting. Just an overlay when the setting widget pops? If so, maybe working with a QDialog (a modal one) would be better.

@jsulm @mrjj @ig Thanks for all the help.
I was able to fix the inheritance issue by creating a new FileMenu instance in the main window.

@NIXIN You have a QMainWindow inside splitter?! I doubt that. You should have two widgets: for the left side of the splitter and for the right side of the splitter.

@Ongsk Title bar decorations are managed by your window manager. You can change them (at a user level only) by changing your theme. This applies to osx, linux, and windows.

If you want to force a specific color then you could make a window with a custom title bar and draw it however you want. Things like Chrome do this. Then they have an option to "use system title bar and borders".

IMO, unless you are making a fully custom window like a video game launcher, or splash screen, or something like that you should let the window manager decorate the window. People customize their WMs to look how they like and standard looks are a foundation of GUI development.

Here's a post from @mrjj that shows you how to do it in windows with native calls (Qt doesn't have a call for it) in case you insist on forcing a color on your users. https://forum.qt.io/topic/85837/change-window-title-bar-color-in-windows
Keep in mind that will be for windows only so if you compile for linux or osx it will not work.

@magicstar
Thanks i landed up using this.
Worked

@L-Koziarz
Yep its sounds somewhat convoluted
but never the less - exciting approach .
I wish it had worked as prof of concept but it seems there are issues.

@Ocram10 said in Resize QMainWindow and QDialog:

proprietà di windows "Ridimensionamento e layout"

Dove trovi questa variabile?

@Fuel the exemples in pyqt-master do it automatically but i don't understsnd what event or property they use

@eDeviser said in Customizing QMainWindow by style sheet:

Yes, this helps!

I see the QMainWindow holds a QWidget which is set as cetralWidget. So It would be necessary to set the QMainWindow as centralWidget or to apply my css for the QWidget.

Thank you for this hint.

You have to apply your css in your qwidget !

Your css should be :

centralWidget {
background: yellow;
width: 10px; /* when vertical /
height: 10px; / when horizontal */
}

centralWidget:hover {
background: red;
}

Great !

Thanks for coming back with the information !

Since you could make it work, please mark the thread as solved so other forum users may know a solution has been found :)

Hi, and welcome. The image upload function on our forum is broken, the uploaded images might be visible to you, but they aren't to anyone else. See this thread for a workaround.

@mrjj
Thanks for the reply!
I followed your advice and tried setting the panelWindow as the parent...
No change..

Any other ideas?
I followed this link,
http://doc.qt.io/qt-5/qmacnativewidget.html#details

Hi SGaist and thank for the help.

For the code being in the constructor when it should not be, I only did it that way to have the simplest code possible to show my issue. I understand and agree with your point. I am working on an already existing application, I created this QtCreator project to isolate and replicate the issue. I do not call QWidget::show() in the constructor of my application.

I have made an important discovery while working on this issue: calling blue_widget->show() at the end of my code in my QtCreator project does fixe the problem, but doing the same in my application does not fix the issue. This is the 1st time I see a different behavior, I thought I had manage to have the same 1:1 behavior between the QtCreator project and my application.

Thanks for the help, I will keep looking.

@pauledd
:)
class MyWidget : public QWidget << yes that is subclassing :)

Also, a widget can only paint on it self.
its not possible to paint on other widget from inside a
paintevent.
Thats why the first sample didnt work. You asked painter to paint on tab from inside mainwindows paintEvent :)
I guess you already found out but its just to make clear for other readers.

@SGaist
I just want 1 window with the forms changing for the login and presentation windows.
And then ill use dialog windows after the presentation window.
Anyways thank you. Ill try QStackedWidget.

I need to be as big as the screen.
Before I used this code to display it as big as the screen

int Height = 0; int Width = 0; foreach (QScreen *screen, QGuiApplication::screens()) { if(QGuiApplication::primaryScreen()->name() == screen->name()) { QRect rec = screen->availableGeometry(); Height = rec.height(); Width = rec.width(); } } w.setFixedSize(Width,Height);

Unfortunately, I do not know why, the height is still longer than the screen. This is why I decided to use showMaximized (), unfortunately this does not seem to go well for both systems.

Thank you all, I will try to use your advice.

@AyushExel204
It is indeed strange. I haven't worked with that library, but I see no good reason that is should work with VlcMediaPlayer but not with VlcMediaListPlayer. In this example (graciously provided by @mrjj over chat), they don't seem to use VlcMediaListPlayer and as you said that should work. Perhaps you can use it to build upon. Also you might want to search through the library's bugtracker to see if there is something known about this issue.

Hi, just to want add, while Qt Creator's capturing of your qDebug() output is usually 100%, but if you want to be sure to get everything, you could try running DebugView when your app exits.

I had to add Q_OBJECT and also delete my debug folder once, to get rid of a few link errors.

Also got rid of the QThread subclassing, it is way easier to create a worker class and connect it through signals. There is really a lot of outdated example code out there.

Thanks for your help!

IMO it's a code smell to rely on the OS to clean up for you.

We run all of our unit tests through valgrind as part of our build process, so that a memory leak breaks the build.

QT leaves a ridiculous amount of memory lying around, which of course kicks off valgrind.

We've got a huge suppressions file which we have to install for every GUI related unit test, and the sheer number of suppressions makes valgrind run slower, so has resulted in longer build times.

So yeah, in my opinion, it would be nice if QT didn't do that.

That's not how it works and not something I would expect either.

The mdi sub-windows will only extend in the mdi area, nothing more.

The behavior you are looking for, you'll have to implement yourself.

Basically, it's not a part of Qt that you access directly. It's part of the platform plugins that abstracts away the differences between the various supported OSs.

The best I can recommend is to contact the KDE folks about how the startup notification is handled by them.

Hi,

One way to do it would be to set the minimal size of your central widget or the maximal width of the QDockWidget contained widget.

Hope it helps.

@kshegunov

I think I got it! I have included to the painterEvent the following:

QPixmap pm(200, 200); pm.fill(Qt::white); setPixmap(pm);

Now I can set the text from other class like:

ui->label->setText("lala");

However, I think I shouldn't set Pixmap inside paintEvent - better to do it in the other class so this type of label could be also used for other labels, right?

EDIT:

I liked the idea of @jsulm. Could you give me some hints how to achieve it? How to get the painting functionality from a standard QLabel and then add some additional my own painting?

@Chris-Kawa
Totally agree.

I'm not that fluent in python, but

layout_final.addWidget(self.widgetGL) layout_final.addWidget(self.widget)

Horizontal layouts add stuff left to right, so, if anywhere, the GL widget would be on the left, not on the right.

I don't think a GL widget has any minimum size. It might be that the other widgets have "greedy" horizontal size policies (I think a label does by default). Try setting a minimum width or an expanding horizontal size policy on the GL widget.

Right.
This is not the first time I made such mistake. So the lifecycle of GraphicsScene is required for graphics view.

Thanks for the help. This is solved.

Hi, thanks!

I call the child QMainWindow from the parent QMainWindow as follows:

self.responseBox = responseBox(self)

This is the code initializing the child QMainWindow:

class responseBox(QMainWindow): def __init__(self, parent): QMainWindow.__init__(self, parent) self.setWindowFlags(QtCore.Qt.Window | QtCore.Qt.CustomizeWindowHint | QtCore.Qt.WindowMinimizeButtonHint | QtCore.Qt.WindowMaximizeButtonHint) self.setWindowModality(Qt.NonModal)

The full source code of the application is available online:
https://github.com/sam81/pychoacoustics
The child main window is created on line 834 here
and the code initializing it is here

I'll try to generate a small reproducible example and post it here as soon as I have time.

@SGaist Hi. Currently the default QDockWidget title bar shows label and close and float buttons. When you have 2 QDockWidgets tabbed, than the QTabBar appears abowe the title bar (if set to show QTabBar on North). I don't like this behaviour when you have title bar with label and abowe that tab with same label. It looks weird. It is not needed to have 2 labels. I know i can have custom title bar widget, but that means i will need somehow to handle when the QTabBar is visible and when not (to show/hide title bar so there are not redundant informations like label).

It could be best if i can hide the QTabBar, but still have that tabbify behaviour and some signal that is sended when QDockWidget is tabbed, so i can show everything in my custom title bar (like all tabs in that area, close/float buttons and other things i need).

I will probably need to copy all the files from Qt and do it by myself (qmainwindow, qmainwindowlayout, qdockarealayout, qdockwidget), but this will take lot of times as i saw it is around 10k lines of code.

@maximo
Ok :)
I am going to test again with stylesheets.
It would be very nice it it worked as docs says.
Or at least to understand why it did not.

Update:
Ok, one must unpolish/ polish each widget as doing it to
Mainwindow doesn't seems to work.
But it also works with
setStyleSheet(styleSheet());
in MainWindow to reload (whole) style sheet.

Update 2:
Ok. Having qframes with bool error property.
It will update in Designer, if setting it.
No code. Sheet on MWindow.
So it does work with properties it seems.

@SGaist The icon size is saved via QSettings in a QDialog called from a QMainWindow subclass. After the dialog is closed, QMainWindow::setIconSize() is called.

@mrjj Thank you !! It's working

You can't get a position of your window inside that window's constructor because it doesn't have one yet.
The window manager of your OS gives your window a position when it is first shown (or if you explicitly called move() before).
The window is shown when you call on it show()or any of the related functions like showMaximized().

After the window is shown you can get the window position including window frame with pos() and without the window frame with geometry().topLeft().

@Chris-Kawa I have found some threads (like https://forum.qt.io/topic/3765/moved-painting-in-the-nonclientarea) but the link to http://developer.qt.nokia.com/forums/viewthread/3331/ is dead and this very bad.

Yes my bad, I pointed you to the wrong property. Actually you must set the windowModality property : http://doc.qt.io/qt-5/qwidget.html#windowModality-prop, or the modal prop (only for QDialogs) : http://doc.qt.io/qt-5/qdialog.html#modal-prop. I believe that is the solution you've been looking for.