General and Desktop

@Jonathan-Levanon Good found. nice overlay class :)

@jsulm hi, i under stood that line in wrongly. in the place of <char *>, i have used const QByteArray. Now i got the point after going trough the type casting page, adviced by you. Now it is working. Thanks to all of you.

Fortunately in our case the connection via QTcpSocket::connectToHost() without need QTcpSocket::bind() is sufficient. However, this may change in the future, and it may need to specify the outgoing network interface, so the problem of stacked binding of QTcpSocket will be there again. I found hypothetic scenario in which things might go worse if an error occurred. Imagine having two network interfaces labeled as N1 and N2. N1 is disconnected from the network. If the user accidentally decides to bind via QTcpSocket::bind() to N1, the connection fails. Changing the connection to N2 is now impossible. I guess it is impossible because QTcpSocket is still bounded to N1, so rebind to N2 fails and the connection to N2 is not possible. Do you know how to reset QTcpSocket to use QTcpSocket::bind() again?

@Hetal no you don't need to call qDeleteAll in that case, since the QSharedPointer takes care of it. If the QList is also created on the stack you don't need to delete it too. The question is, do you need the (little) overhead of QSharedPointer at all?!

@Devopia53 it works! , Thanks alot

@philo_neo said in No valid Kits found: Hello, I work under Fedora 28 server x86_64, I installed Qt, with this command line: dnf install qt-devel qt-doc qt-creator. But when I make new project empty into Qtcreator 4.6.2 it returns to me: No valid Kits found .... I had to forget a something but what? Hi, I'm by no means a linux expert, but when I installed qt via the commandline, instead of the online-installer I had to specifically tell QtCreator the path to the compiler. Everything else was detected automatically. Don't have my Linux machine here right now, but this is where the compiler path should be: [image: c146e271-522f-4f5b-9935-70ba022e6e5d.png]

@Mr-Pang said in QScrollArea layout tips in designer?: But sometimes I want to append a sub-layout and then put two or more widget into it Then do it. A layout can contain other layouts and so on...

@Land_Outcast said in Qt for ebook readers (slanted text question): I got the following answer from Kovid Goyal: It doesn't have anything to do with calibre. Font interpretation in the view components of both sigil and calibre is done by Qt WebKit. You'd have to ask the Qt developers why that happens First, understand this: Here, WebKit is the component that renders your EPUB file. WebKit itself is a very large piece of software, and it's independent of Qt. "Qt WebKit" merely provides a way to integrate WebKit into Qt-based software. Unless I'm mistaken, Qt itself has no control over how WebKit renders anything. So my questions are: Does your slanting issue occur with other WebKit-based EPUB readers? What version of Qt WebKit do Sigil and Calibre use?

Thanks! I figured out a different way and forgot to check the forum. I used: onCurrentIndexChanged:{ visible: { switch(currentIndex) { case 0: return true; case 1: return false; default: return false; } } } Thanks for all of the help tough!

@Buckwheat Thank you documents link. I will read it and trying to make change in my code. thank you @Buckwheat .

If you have a customer that can reproduce it, get a crash log from them. You should be able to get the crash line from that and start looking into it from there. If you build for windows with MSVC you can always generate the .map file with your build and save that off. Then you can determine what line of your code the crash was on from their crash log (with no lines/function info). Another option is to leave debugging symbols in and get a full backtrace. If you are working with a posix compiler like clang or g++, then just don't strip the exe and build with -g. That should give you plenty of info to work with. The AA_UseDesktopOpenGL flag will cause Qt to use the system libgl.so (or the windows equivalent, sorry not a windows guy). This can definitely cause problems since that can be a different version than you're code or Qt is expecting. Could cause crashes or other graphical bugs. Forcing it to AA_UseOpenGLES would be a good first step in debugging the problem as well.

@SGaist [image: Screen_Shot_2018-06-25_at_3.26.44_PM.png] Okay so got the image uploaded. My intention is to plot that scatterplot on the image itself. So I was thinking that I got the scatterplots points then select those points on the image and convert the pixel color of those particular pixel as it would be easier for the user to figure out which part of the pictures are being selected. But I am unable to see any changes on the images. Could you guide to as to what is wrong in my code or is there a more efficient way to get it done. Thanks.

@Johnx8664 Learning Qt4 at this point would be a waste of your time. Like @SGaist said it's long past it's end of life. Qt5 is 12 major releases into it's life cycle now and 5 years old now. I would grab a book on Qt5, or I find it's pretty easy to learn Qt just from the docs that come with it. If you know C++ well (and you should if you are tackling Qt), then you should be fine learning from the Qt Assistant docs. There are a lot of examples and tutorials in there as well.

@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.

Hi, Are you calling moveToThread anywhere in your code ?

Hi and welcome to devnet, You can find the reason using the three last parameters of the setContent method.

@SGaist Ok. Thank you.

Hi, The quick and easy first would be to take a look at the release notes between 5.10 and 5.11.1 to see if there's anything related to OpenGL it them.

I never got this fixed, but I decided that having two places to select the MAC address was a bad idea anyway, so I replaced the QComboBox with a QLineEdit. Added this line to my main widget: mapper->addMapping(ui->lineEditMacAddr, MODEL_COL_MACADDR); And it seems to work fine. Marking as solved...

Hello everyone, thank you for the answers. @mrjj You are correct, I also just found this page that describes exactly what you are saying about overridding the paintEvent class. Thank you everyone!