@Annabelle said in Qt Programming Language:

And now when I try to compile my "Hello World" project, I get this error.

The error says that your compiler is too old and it doesn't support the C++ 2011 standard. But I'm confused: If you're doing a basic C++ Hello World program, why is Code::Blocks trying to include Qt?

I suggest you leave Qt out for now. Just focus on learning plain C++. This way, it doesn't matter if you have an old compiler.

@Hronom: Did you try it with QtAudio3d? I don't want to use it, I am only interested, if it works

@Thomas Zander: QML doesn't have really much opertunities as in Qt4. And if it's not easy to do it in QML, it will never work in QML, which means, that QML is a language with limits, but you can implement very fast simple widgets. That's the reason, why I prefer C++. I will learn QML, when I got time for that, but now, I only developping complex desktop applications for Linux, Windows and Mac and need their styles.

You can do it, click on the "Topic Tools" button, you have there the "Mark as solved" entry.

@werispaul did you found a solution to this compiling error: "QtGui/QPlatformDialogHelper": No such file or directory?
I have similar problem with missing headers, when compiling Qt from git.

Yep, I will probably agree with you here. I hope this doesn't look like we are offending doforumda, because we don't.

Yes i have installed it and it is working fine so far, also it is very usefull too. It is a little bit slow but i don't think that this is a plugin-issue.

Thanks, Zap. Don't sweat it too much; I may not be explaining it well, but I'm almost sure it's no big deal to do.

@jsulm
In the code, it read using ```

bool ReadModelData(istream &in, functionname &_PS) ... ... ReadModelData (fin,s) ...

The path of the text file was added in the "project" > run of "Desktop Qt 5.6 MSVC2015 64 bit" > "Arguments". File path
When I debug it just show in the Application output:

Debugging starts Debugging has finished

and when run the code the results are cpu=0 z=0 ... while they should be some non-zero.

Just ran up to "this":http://www.mobile-review.com/articles/2011/birulki-115-en.shtml news. More info about the phone they gonna use in the unexpected merge.

You can reffer to this link as an example http://doc.qt.io/qt-5/qtwidgets-widgets-calendarwidget-example.html

Of course I'll cast my -1 vote as well.

I'll add to point 1:

If the data contained in the model is all of basic types or implicitly shared types then it's possible to already use the current framework without ever triggering any expensive* copy

, to point 2:

There's no clarity on how to support different types in different roles would we need an additional template argument for each used role beyond Qt::UserRole? is so the problems above grow exponentially with the roles

And to point 3:

No possible implementation for a reliable dataChanged emission if model internals are exposed directly

*expensive = a copy that implies more that a:

memcpy of less than 65bits and an increase/decrease of a numeric reference counter

Hallo jungs und mädels, frohe Weihnachten!!
Ich beschäftige mich grad mit dem modell view konzept um eins meiner Projekte zu realisieren!
Ich hab euer Tutorial gefunden und wollte es durcharbeiten! Aber leider sind alle links zu den dateien und des tutorials tot. Könntet ihr das tutorial vllt wieder auffrischen?
Das wäre sehr hilfreich für mich!!
Liebe Grüße!!

I had the same problem, and substitute:

toAScii -> toLatin1
fromAScii -> fromASCII

Works fine to me too,

Thanks for sharing the code.

Nothing wrong, much less "vastly inferior" with Qt containers - their performance is on par with std containers, and Qt containers use is actually less verbose and much easier to use. std containers are overly verbose, pretty much all operations require iterators.

He is right about the pricing though. It needs to be cut at least in half to become reasonable.

@postmako I tested the Native_Build_of_Qt_5.4.1_on_a_Raspberry_Pi steps as pointed in your wiki.

Any chances you'd have pointers to make it work with PyQt5. I have install PyQt5 (pip install python-qt5) but I am getting this:

pi@raspberrypi ~ $ python Python 2.7.3 (default, Mar 18 2014, 05:13:23) [GCC 4.6.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import sys >>> from PyQt5 import QtCore, QtGui, QtWebKit Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: cannot import name QtCore

No sure how to read this message. I'd guessing that it still can't find Qt5 (?)

@jsulm
OK it means src_gray value in .cpp file should be same as in mainwindow::on_Track clicked() src_gray value.
Actually src_gray is image array.
I did it by Define the value of src_grey in function as
src=imread("/file.jpg);
cvtColor( src, src_gray, CV_BGR2GRAY );
so i will get src_gray value.

Ich mache mal einen neuen Thread auf.

@juaniyoalm
Well good work then. :)
Please mark as solved.
You can always make new posts
for new problems.

and happy programming.

Sehr gut. So kommt die Absicht deutlich rüber.

@Naveen_D Well, you use them as in any C++ application. You first need to learn the API. Read documentation, take a look at the examples, try to write simple applications,...

hi, I still have a question about it.
when I click on the start game button and I want the background to be the same and just a table.

is it going to make some code? or over new .cpp with background?

Thank you very much !

Thanks Alex, see you soon :)

I was afraid that your @kde.org address is not functional... (some ppl rarely check those)

[quote author="Wolf P." date="1292095516"]Splice genes, while I have an eye on the robots ;)[/quote]

You're lagging behind, Wolf. You're supposed to breed dinosaurs now. :P

Hi
You can take the highlighter from here
https://doc.qt.io/qt-5/qtwidgets-richtext-syntaxhighlighter-example.html
(the sample is in creator already )
and instead of having the question code in a QLabel, use TextEdit as @KillerSmath says.

@SGaist @JonB @VRonin : So i took a deep breathe and tried to implement my code from scratch using @VRonin solution i.e. his latest fork https://github.com/VSRonin/qtmodelview.
Now my code is working :). This was the piece of line which helped me:

const QModelIndex parentIdx = index(0, 0); const QModelIndex xValueIndex = index(0, 1, parentIdx); setData(xValueIndex, 2.55);

Additionally deep inside my code i had two pointers to my view which was also the cause for not showing the new values. The thread can be closed. I have a request @VRonin if he could take out the link to the code as it is a part of commercial project. Thank you everyone for your help, especially @VRonin.

@andsun this thread is 3 years old, not relevant anymore. Except of course it happens with the new forum too.

It popped up in your unread, as we migrated. Everything looks new and shiny, and the system thinks everyone is logging on for the first time (which we technically are, as the login changed to Qt Account).

You're welcome !

Don't forget to update the thread's title appending solved so other forum users may know a solution has been found :)

@jsulm

Thank you i had solve the problem
Thank you so much!!!!

Cześć,
zwą mnie Michał i widzę że nikt tu od roku nie zagościł, więc pora na mnie.
Pozdrowienia z Lublina!

No sweat, Volker...I appreciate your help. Would you like a fresh copy of the source code? Mine should be about the same as yours, but...you never know.

Again (mentioned this before, I believe), take a look at QFileSystemModel. It does this for you already. If you don't use it yourself, then you might study its source code to find out where it gets the images from. Or, look into QFileIconProvider. If you are using QSystemStorageInfo as your data source, then you also know which drives are a CDRom drives. Set the correct flags for those drives, and presto.

Are you using Qt's provided MinGW ?

@jrod2much glad you solved your issue. In appreciation to all the people that helped you with it, please don't forget to mark your post as solved!

Is there any new idea guys? The recent result I got was:
https://qt-project.org/forums/viewreply/144622/
https://qt-project.org/forums/viewreply/144623/

I resolved the problem.
the g++ compiler was not installed, gcc was.
After installing g++ QtCreator start to open projects normally.

I think this is the bug in QtCreator.
They should add g++ to dependences or change subj error message to more correctly one.

[quote author="texrat" date="1378237198"]You're doing great work Leon (no surprise)! :)[/quote]

Thank you :) The videos are result of a lot of great team work dedicated to the community driven port of "Qt for Tizen":http://qt-project.org/wiki/Tizen.

[quote author="advseo32" date="1375434213"]i have posted this question because is similaire topic but now is Qtableview

Sorry, if i'm wrong , i will post another thread :)[/quote]Yes, please post in a new thread. It is NOT similar.

Each thread is supposed to have 1 topic, but you already have 5 topics:

How to automatically insert a row at the end when the user clicks/presses a key there How to check if a cell is empty How to add custom symbols to the vertical header How to check if the user selects a different row How to check if the user has started typing into a row (Your new topic) How to modify headers

The title of this thread is "Insert row from Qtableview to another", but topics 2-6 are not related to this.

Forums let users search old topics to find solutions solutions. But, if a thread has many topics that are not related to the title, it's hard for someone to search.

@andre Thanks, Andre, for detailed explanation. I understand that your design is solid and well thought. I just wanted to adapt one moment for my needs - disallow checking directory if the child files are not populated yet. And now I finished with code modification as I wrote above. I also mentioned strange behavior in some cases. This little problem still persists. Moreover, I discovered that this behavior takes place in initial CheckableProxyModel class also. The problem arises when directory contains only one file. Then checking of the directory adds the file to the list as expected, but the check mark doesn't appear near the file, it appears only if I move the mouse cursor over that file. If the directory contains 2 files or more, the problem disappears. Could you please check the code? It's enough to create any directory with one file and check the directory

Firstly, you shouldn't do anything but system maintenance with the root user. Secondly, gerrit, being somewhat smart, will want you to configure your e-mail and name. Here[2] it's written pretty clearly how you should set it up. If I had to guess what the problem is, when pulling the Qt's source for development git pulled the git triggers for you, which would happen if you ran:

perl init-repository --codereview-username <Jira/Gerrit username>

which you should have according to this[1]. Getting the triggers in the local repo is perfectly normal and desirable, so my guess is you can't commit currently just because your name and email aren't configured.

Basically you have all the information in [1], [2] and [3], you just have to follow the instructions. Start by cloning the source with your gerrit username[1], set up gerrit [2] and ultimately use it to push for review[3].

[1]: https://wiki.qt.io/Building_Qt_5_from_Git
[2]: https://wiki.qt.io/Setting_up_Gerrit
[3]: https://wiki.qt.io/Gerrit_Introduction

@JonB said in QSqlRelationalTableModel with multiple Joins?:

@devhobby said in QSqlRelationalTableModel with multiple Joins?:

if(MainWindow::isConstColumn(index.column())) QAbstractItemModel::flags(index) & (~Qt::ItemIsEditable);

There is no return statement there??????

Just a typo when I posted the code to the forum, the actual code has it.

@mrjj Working Code

QTreeWidgetItem * addTreeRoot(QTreeWidget* treeWidget, QString name,QString description)
{
QTreeWidgetItem *treeItem = new QTreeWidgetItem(treeWidget);
treeItem->setText(0, name);
treeItem->setText(1, description);
return treeItem;
}

QTreeWidgetItem * addTreeChild(QTreeWidgetItem *parent,QString name,QString description)
{
QTreeWidgetItem *treeItem = new QTreeWidgetItem();
treeItem->setText(0, name);
treeItem->setText(1, description);
parent->addChild(treeItem);
return treeItem;
}

void MainWindow::on_pushButton_clicked()
{

QTreeWidgetItem* root= addTreeRoot(ui->treeWidget,"ROOT","text");

addTreeChild(root,"bbbb","text");
addTreeChild(root,"ccc","text");
addTreeChild(root,"dddd","text");
QTreeWidgetItem* last = addTreeChild(root,"eeee","text");

addTreeChild(last,"eeeee","text"); // notice last as parent

}

How large is it ?

Ah, thanks for the hint. That thread also contains an interesting link to another library:

"QCustomPlot":http://www.workslikeclockwork.com/index.php/components/qt-plotting-widget/

[quote author="Lukas Geyer" date="1326794366"][quote author="deisik" date="1326790823"]Yes, because such is the nature of a void* pointer. The pistol shoots and somebody will surely shoot himself - you cannot make everything bullet or fool proof[/quote]

[quote]The found solution may be dangerous but to me it is by far a more genuine and elegant way of doing this.[/quote]

Well, let's just agree that we have different development principles.

I wish you the best with your solution, but I'm officialy out now as this discussion obviously leads nowhere and is rather pointless at this moment.[/quote]

Hi,

same for me. Just one last word from myself:

I would not try to optimize (and it looks like that to me) before you really know, where the bottleneck is. In one or two (or many) years, some other people might have to maintain the code and will they know what was done there? Will they understand? What will they do if new types will be introduced and they do not fit into this schema?

Just some thoughts.

@SGaist New output (after getting logged out): https://pastebin.com/yJK4tFeQ

Output of diff dmesgOutputBeforeLogout.txt dmesgOutputAfterLogout.txt: https://pastebin.com/5jGtEiUd (differences between two outputs)

don't confuse . use QT Creator

hi JKSH.

I found one error:-

undefined symbol _zn9qlistdata11detach_growepii qt

I am trying to run my application which compiled on different machine(but OS and Qt version is same).

Please give me any solution

Thanks! Almost time to go live!

Yea i think so too and totally agree with u..... with 150million symbian devices more to be launched by Nokia, i am pretty sure that Qt's future is not dark and we should stick to developing for it as well as start taking WP7 seriously and think of developing for it too......
well the futyure is unseen bt if we wish, its not going to be dark with WP7 in hand..... :)
[quote author="Milot Shala" date="1297704869"]
[quote author="Andre" date="1297699907"]Question that is just coming up in my mind:
Does this change in direction mean that bugreports & wishes in Jira that have been closed because focus has shifted to the mobile development will be re-evaluated? It seems mobile is not that important anymore after all...[/quote]

It will be important, there are people still writing Symbian apps because there are lots of Symbian users out there, to the 75 million Symbian devices there will be shipping 150M more devices and these needs new and updating older apps, and of course I think all the bugreports and wishes will be added where appropriate.[/quote]

Hi Arnaud, you are welcome!
I'm glad I could help you a bit with that issue and hope to talk to you again.
Please mark your thread as solved by editing your first post with a prepending [SOLVED] in the title.
Have a nice day!

@Ram_Thakkar77 It sounds like you just don't understand linux properly. It isn't that it is harder than windows (and in a lot of cases it's actually easier), it's just that you don't understand how the program is run and how ld finds your libraries.

There's a term in windows called dll hell which I'm sure you've heard. You are basically just running into a similar situation in Linux but have no idea how it works or how to solve it.

I recommend you stick with it as once you figure it out it's quite easy. The info p3c0 and jsulm gave should have helped you get your distribution ready, but you kept missing libraries and not setting your custom LD path properly. If you do this correctly it is not only quite easy but can all be easily automated in a small bash script.

I definitely wouldn't blame Qt for this as you have a "distributing linux binary" problem, not a Qt one. That would have happened to you no matter what development toolkit you used. It has nothing to do with Qt at all.

Hi all,

I could finally handle the problem, not completely though.
Thanks for your help up to here.

I mentioned it on other thread too and if possible I would like to know your ideas as well.
Please see the screenshot below. I want to know, what stuffs/updates do I need to install please?

http://imgur.com/a/Iru1N

there is also an "Invitation Thread":http://developer.qt.nokia.com/forums/viewthread/3021/

On a side note, the QWebService lib I am writing (some of you might remember it from qt5-feedback) is now ready for RESTful, JSON web services. I've recently put together an example that users QtDN API. Getting JSON reply is doable with 1 line of code (although I use 3 lines in my example app). Available on "Gitorious":http://gitorious.org/qwebservice and, in the future, maybe as part of Qt5. I'll probably post more info on it in the future, in a separate thread. Sorry for any typos, I'm using my phone for this post.

BTW: Would appreciate any feedback on API, intuitiveness, usability etc., as well as help in coding.

Please don't highjack other people thread.

You are already getting answers on your other thread here.

And you should use the complete path to the qmake of the version of Qt you are trying to build the plugin for. Without the path, you are calling your distribution installed qmake. Furthermore this one is for Qt 4.

ThanQ very much you done a great job,it helps to Qt beginers

I am also getting the error when i try to cross compile qt in raspberry pi 2 without x11.
When i am running console application it is running.
But when i am using widget application in pi touchscreen it is showing
"Unable to query physical screen size, defaulting to 100 dpi.
To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters)."
and the system is idle
can anyone help me with this

when i am debugging the output in qtcreator is as follows
Debugging starts
Listening on port 10000
Remote debugging from host 192.168.15.153
Process /home/pi/qtinpitry created; pid = 8079
File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
Unable to query physical screen size, defaulting to 100 dpi.
To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).

can anyone help me.
Thanks in advance

I think I've set everything up. All thanks.

[quote author="great88" date="1376933337"]Is it OK to spawn new thread inside a readyRead() handler and then access and write to tcpsockets ( from the parent thread ) from that thread ? It looks to me that this is not good because sometimes clients are not receiving data . What is the proper way to do this ?[/quote]If your TCP socket is in the parent thread, you cannot write to it from a new thread.

There have been many posts about combining QTcpSocket and QThread recently. Search the forum, and you should find plenty of info.

@RobertoDuran
Hi, you might not catch Peter Winston here easily, he hasn't been around for a while.

However on the licensing, currently our thinking is that students can get the open source package for free and start learning and coding. We are thinking of some form of university/school licensing, but that will take a while to get off the ground.

We are also looking at low cost options to private/small developers. The last time we had that option it really did not sell well, so it was pulled back for now. We know there is demand for a low cost option, but we need to figure out how to provide that option so that it would get sensible sales numbers.

In general we really like it when people contribute back to Qt, be it patches or license payments. Naturally we want to make it easier for people to contribute, so different licensing options are something we continuously look for.

What ever they shared with me regarding the query is related to yocto Only.
With there reply it seems like we also have to move to yocto if we want to finish it with in a time span.

One good way to learn about Qt is to attend training. Here is a link to some scheduled events organized by The Qt Company: http://www.qt.io/events/

In addition, several other companies organize training events around the world. For example, here is a link to some events organized by KDAB: http://www.kdab.com/training/schedule/

@nick784512
Hi
a ByteArray ( dynamic ) would be the best. :)

void SerialPortReader::handleReadyRead()
{
m_readData.append(m_serialPort->readAll());
...

Hi there ,

I'm back again for some feedback , I changed the way I use my Database, I'm still connecting the same way, But all my functions that were in my class get swith into the only page that need those instructions .
That Way I Just connect through my databse page and just make a Signal Slot use when I need it.

That said , my problem isn't solve for now I though maybe it was the Databse but seems not , maybe it's my refresh timer for my UI that creates crashes , anyway I'm still triying to find the problem..

If anyone could give me a clue for Valgrind to work , it's crashing a few seconds after starting the analysis and I just have the message that I post earlier.

That's a big post thank's for help and if I can't get in touch happy Christmas holidays.

@SGaist right you are: I reworded it. Thanks.

@FiveSmart http://doc.qt.io/qtcreator/creator-project-qmake-libraries.html

@gogoer Sorry for the delay, I haven't had time to answer questions on the forums lately..

Anyway, 3 files in that folder is normal.

What happens if you just try to run qmlscene on the command line on the RPI? It sounds like it can't find your install of Qt. Do you have a QTDIR environment variable set? Is Qt's bin directory in your path?

For example my shell looks like:

$ export | grep -i qt declare -x PATH="/home/mike/bin:/usr/local/Qt/bin:/home/mike/bin:/usr/local/Qt/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/usr/local/bin:~/scripts:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/usr/local/bin:~/scripts" declare -x QTDIR="/usr/local/Qt"

You can also use a qt.conf file to point to your installed libs from your application directory.

Solved. The missing libQt5SerialPort.so.5 error on the target device was because that library effectively was not present. On the host side I added that library in the package list of the image and rebuild the image itself.

@J.Hilk said in QString::toShort problem:

this seems to be the internal call, and thats the call for every overload - seems like there was more intended once.

There is a bugreport about this but currently without any real solution:
https://bugreports.qt.io/browse/QTBUG-1098
https://bugreports.qt.io/browse/QTBUG-53706