Enabling and Disabling Window Widgets?



  • Is there anyway (that works) to enable or disable specific window widgets?

    I've tried using the window flags to set the enable and disable specific flags for specific window widgets to prevent resizing and or maximizing a window, but it doesn't work and the widgets are still enabled.

    I'm using Qt 5.11 on an iMAC running iOS Mojave.

    Having just searched around for alternate solutions, I haven't tried but will when I get back to my system...getting the widget and then calling setEnabled(true/false) directly instead of using the window flags (setWindowFlags).


  • Lifetime Qt Champion

    Hi,

    Can you provide a minimal compilable example that shows what you are trying to do ?



  • I'll try tonight when I have access to my system...it isn't difficult to replicate, presently I'm modifying the window flags to disable window widgets, but it doesn't seem to work.



  • @SPlatten
    you can try the Qt::MSWindowsFixedSizeDialogHint window flag together with setSizeGripEnabled(false)

    the flag is obviously for Windows only, I'm unsure what the equivalent is for MacOS.

    This however should prevent the user from resizing the the (standalone) window without removing the buttons or borders all together.

    This is what I think you're trying to do. Correct my if I'm wrong.



  • Thank you, I am looking for a method of programmatically enabling and disabling any of the widgets (close/minimize/maximize/context help/title/system menu). Also the solution needs to be compatible with Windows, Linux and iOS.



  • Here is the code I use to set the window flags:

                if ( strPropName.compare(clsXMLnode::mscszPropertyClose) == 0 ) {
                    if ( strPropValue.compare(clsXMLnode::mscszTrue) == 0 ) {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              | Qt::WindowCloseButtonHint);
                    } else {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              & ~Qt::WindowCloseButtonHint);
                    }
                } else if ( strPropName.compare(clsXMLnode::mscszPropertyFrameless) == 0 ) {
                    if ( strPropValue.compare(clsXMLnode::mscszTrue) == 0 ) {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              & ~Qt::FramelessWindowHint);
                    } else {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              | Qt::FramelessWindowHint);
                    }
                } else if ( strPropName.compare(clsXMLnode::mscszPropertyMaxmize) == 0 ) {
                    if ( strPropValue.compare(clsXMLnode::mscszTrue) == 0 ) {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              | Qt::WindowMaximizeButtonHint);
                    } else {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              & ~Qt::WindowMaximizeButtonHint);
                    }
                } else if ( strPropName.compare(clsXMLnode::mscszPropertyMinMax) == 0 ) {
                    if ( strPropValue.compare(clsXMLnode::mscszTrue) == 0 ) {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              | Qt::WindowMinMaxButtonsHint);
                    } else {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              & ~(Qt::WindowMinMaxButtonsHint
                                                                                | Qt::WindowMinimizeButtonHint
                                                                                | Qt::WindowMaximizeButtonHint));
                    }
                } else if ( strPropName.compare(clsXMLnode::mscszPropertyMinimize) == 0 ) {
                    if ( strPropValue.compare(clsXMLnode::mscszTrue) == 0 ) {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              | Qt::WindowMinimizeButtonHint);
                    } else {
                        pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                              & ~Qt::WindowMinimizeButtonHint);
                    }
                }
    

    The above is typical for all flags. pobjWidget:

    if ( strNodeName.compare(clsXMLnode::mscszNodeWindow) == 0 ) {
            pobjWidget = static_cast<QWidget*>(pobjCtrl);        
    }
    

    In the above example pobjCtrl will be a pointer to the window widget. This works for the minimise widget, it doesn't work for the close and maximise / restore widgets.

    [Edit] Found some posts online which detail how to disable resizing:

     setSizeGripEnabled(false);
    

    I would have expected that since flags exist for these to work, they don't. This won't solve my problem as the method is part of QStatusBar, my window doesn't have a status bar and shouldn't need it to disable sizing.

    QWindow has a method called setFlags, is this the same as calling the setWindowFlags on the widget?

    @J.Hilk, Just reading your post again, yes your solution is for windows only. How do I do this for Windows, iOS and Linux, I would have thought this would be handled by Qt.

    @SGaist, is the code I've posted sufficient?



  • I tried:

                    pobjWidget->setWindowFlags((pobjWidget->windowFlags() | Qt::CustomizeWindowHint)
                                                                          & ~Qt::WindowMaximizeButtonHint);
                    QRect rctGeom = pobjWidget->geometry();
                    pobjWidget->setFixedSize(rctGeom.width(), rctGeom.height());
    

    Didn't work widget still accessible.


  • Lifetime Qt Champion

    @SPlatten said in Enabling and Disabling Window Widgets?:

    @SGaist, is the code I've posted sufficient?

    No it's not, it doesn't allow anybody to easily reproduce what you are doing.


  • Qt Champions 2017

    Hi
    If i may suggest a different approach.
    Try running
    http://doc.qt.io/qt-5/qtwidgets-widgets-windowflags-example.html
    on your platform(s) and see what the combinations gives/shows.



  • @mrjj , Thank you, I'll try this tonight, 7:40 am now, I'm not back at my system until 18:00 tonight.



  • @mrjj, I downloaded all the files and built the demo, just to recap, the version of OSX I'm running on my macBook Pro is High Sierra version 10.13.6.

    The version of Qt is 5.11.2 (Clang 8.0 (Apple) 64 bit). I would love to say the application worked and has solved all my problems, I was planning to debug it and then replicate how it works, sadly its no better than my code.

    This is what I've done, launch the application, the default settings are:

    Radio buttons, Window selected and Preview child window displayed.
    All checkboxes unchecked.

    Here is what happens:

    MS Windows fixed size dialog
    unchecked, I can resize the preview window
    checked, no effect on preview window, I can still do everything I could without it checked

    Frameless window
    unchecked, window title and widgets visible
    checked, window title and widgets removed

    No drop shadow
    unchecked, window has drop shadow
    checked, window doesn't have drop shadow

    Window title, unchecked or checked, no effect
    Window system menu, unchecked or checked, no effect
    Customize window, seems to have same effect as Frameless window
    Window minimize button, unchecked or checked, no effect
    Window maximise button, unchecked or checked, no effect
    Window close button, unchecked or checked, no effect
    Window context help button, unchecked or checked, no effect
    Window shade button, unchecked or checked, no effect

    Window stays on top
    unchecked, window doesn't stay on top
    checked, window stays on top

    Window stays on bottom, unchecked or checked, no effect

    Overall very disappointing it seems that most of the hints have no effect at all, surely this is a bug that needs attention ?


  • Lifetime Qt Champion

    Just to be sure we are on the same page: are you trying to develop a desktop like application for iOS ?



  • @SGaist, I'm trying to develop a desktop application that ultimately can be run on any OS supported by Qt, including Windows, iOS and Linux.


  • Lifetime Qt Champion

    You have to take into account that iOS and Android don't offer the same kind of window management as the desktop OSs and that's nothing Qt can do about. For example, on mobile OSs you usually have one full screen application where you can have some dialogs but it's not comparable to what Linux, macOS or others have for you through e.g. Xorg or wayland.



  • Sorry, I forgot to add OSX to the list and thats what my tests have been on my MacBook Pro running OSX High Sierra version 10.13.6

    I accept what you are saying with respect to Android and iOS, but the isn't one of those.

    Please download the same example code as posted in the link by mrjj, report back with OS version and Qt version if you find anything different...


  • Qt Champions 2017

    @SPlatten
    Hi
    Sorry should have mentioned it.
    The samples are directly available in Creator with a normal install.
    alt text

    Sadly i cant help testing as i have no access to any Macs.



  • The point is Qt is supposed to be multi-platform, I don't have a Windows PC or Linux, only Mac's and clearly it doesn't appear to work.


  • Qt Champions 2017

    @SPlatten
    Well not all hints are supported on all platforms.
    The name is often a give away
    like Qt::MSWindowsFixedSizeDialogHint
    Note the MS in front.
    or like X11BypassWindowManagerHint which is for linux / X11
    Its mention here.
    http://doc.qt.io/qt-5/qt.html#WindowType-enum

    The MSWindowsFixedSizeDialogHint do work on Windows.
    alt text



  • Sorry, for a product as mature as Qt this isn't what I would expect, I know this kind of thing is perfectly possible, just Qt doesn't currently work correctly.


  • Qt Champions 2017

    @SPlatten
    Well it depends on platform and the Windows manger in use.
    Some combinations are not possible in Windows either.
    Also some windows mangers on linux also ignore certain Hints.
    You are aware that Qt does not draw the decorations by its self ?
    Its handled by the OS and might not offer any way to apply it
    and Qt would have to resort to custom drawn decorations.



  • The fact that it can be done using Xcode means its very possible go do, if Qt didn't rush out quite so many versions, the quality control would be better and the releases more functional.

    I'm a big fan of Qt and have used licensed versions of Qt for defence applications, licenses are not cheap and considering the money involved i would be a seriously disappointed by this show stopping lack of functionality.

    In less than 2 years I've seen Qt go from 5.1 to 5.11 and still going, releases seem to come out very frequently, which is good in one sense but at what cost?


  • Qt Champions 2017

    Well i can relate to that. Personally i would rather have more
    QWidgets/Desktop than 3D and QML/Mobile but
    the commercial side of Qt must try to focus on the marked
    trends.


  • Lifetime Qt Champion

    Qt 5.1 was released 5 years ago in 2013.



  • @SGaist , ok, still a lot of releases in a short space of time, the functionality I'm trying to use is very fundamental...shouldn't that be addressed?


  • Moderators

    @SPlatten As @mrjj said window decorations (including the close/minimize buttons) are NOT handled by Qt. Those are handled by the OS. And different OSs are different here (even different window managers on Linux differ here). You can still do this using native APIs.
    If you think this should be part of Qt you can file a change request.



  • @jsulm, thank you, how do I submit a change request?


  • Moderators



  • Thank you, I will complete this now....

    Done, https://bugreports.qt.io/browse/QTBUG-71814



  • @jsulm , if you can see my first posts I am OR'g in Qt::CustomizeWindowHint with each bit. I will try the WindowFlags example as I cannot guarantee that I did the same when testing with that.



  • There is sum good news and some strange findings, I am running the WindowsFlags example on my macBook Pro.

    The setup is as follows, from the Type radio buttons, the Window is checked. From the Hints checkboxes, Customize Window is checked.

    With no other checkboxes the window appears with no title and no widgets, it isn't resizable.

    With 'Window minimize button' checked, the title is visible and only the minimize widget is visible.

    If I then enable 'Window maximise button', the maximise widget is enabled along with the minimise widget.

    If I enable 'Window close button', the close widget is enabled

    Toggling 'Window Title', 'Frameless window', or 'Window shade button' have no effect.


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