qt

What is the correct Qt idiom for exposing signals/slots of contained widgets?

Suppose I have a MyWidget which contains a MySubWidget, e.g. a custom widget that contains a text field or something. I want other classes to be able to connect to signals and slots exposed by the contained MySubWidget instance. Is the conventional way to do this: Expose a pointer to the MySubWidget instance through a subWidget() metho...

Can't start gdb.exe in Qt Creator

I have a project in Qt Creator that builds fine, but when I try to debug it I get this message: Adapter start failed Unable to start gdb 'C:\Qt\2010.02.1\mingw\bin\gdb.exe': Process failed to start: The directory name is invalid If I navigate to the debug build folder and directly run my compiled application, it will run fine, but ob...

click feature in Qt

Hi, I just want to clarify, weather the feature is present or not in Qt. The scenario is like this, I have a list view with items, I want to place the icon to the listview when the item is selected. The selection I mean is, first time when I click item should be selected, next time if I click the same item then it should display some ...

exchanging 2 memory positions

I am working with OpenCV and Qt, Opencv use BGR while Qt uses RGB , so I have to swap those 2 bytes for very big images. There is a better way of doing the following? I can not think of anything faster but looks so simple and lame... int width = iplImage->width; int height = iplImage->height; uchar *iplImagePtr = (uchar *) iplIm...

Using Qt signals/slots instead of a worker thread

I am using Qt and wish to write a class that will perform some network-type operations, similar to FTP/HTTP. The class needs to connect to lots of machines, one after the other but I need the applications UI to stay (relatively) responsive during this process, so the user can cancel the operation, exit the application, etc. My first th...

Qt -how to know whether content in child widgets has been changed?

In QMainWindow I have 2 QSplitters. In that splitters I have QTextEdit, QLineEdits, QTableWinget, Ragio buttons and so on... I want to know if somthing has been chaged after pressing File->New menu button. Is there any general method for doing this? Somwhere I have read that it is recomended to use isWindowModified() function of QMainWi...

What is 'System Usage Specification' ?

My software is a video-audio converter and video cutter. I have used Qt(compiled from source) and ffmpeg (compiled from source). I have to prepare System Usage Specification outline and Specify Usage patterns of the system and indicate it using Run charts / Histograms. I am told to use Winrunner for this purpose. I don't know exactly wha...

QProgressBar problem with uploading

Hey all! I show my code first, then I explain my problem: ... // somewhere in the constructor progressBar = new QProgressBar(this); progressBar->setMinimum(0); progressBar->setMaximum(100); ... connect( ... void MainWindow::updateProgressBar(int bytesSent, int total) { progressBar->setMaximum(total); pr...

Signals and slots in PyQt

In the past I've had some experience of Qt in C++. I've now started using PyQt, and finding it a bit bewildering. There doesn't seem to be any definitive source of documentation, apart from a small amount at Riverbank. I guess the first thing I'd like to know is that there's an initial hump with PyQt, and it does get easier. [Edit: The m...

Serialization with Qt

I am programming a GUI with Qt. In my GUI I have a huge std::map. And "MyType" is a class that has different kinds of filds. So, in a word, I want to serialize the std::map. How can I do that? Does Qt provides us with neccesary features? ...

Does QThread::sleep() require the event loop to be running?

I have a simple client-server program written in Qt, where processes communicate using MPI. The basic design I'm trying to implement is the following: The first process (the "server") launches a GUI (derived from QMainWindow), which listens for messages from the clients (using repeat fire QTimers and asynchronous MPI receive calls), up...

Encrypt/Decrypt SQLite-database and use it "on the fly"

Here's the thing: In my Qt4.6-Project, I use a SQLite-Database. This database shouldn't be unencrypted on my harddrive. So I want, that on every start of my program, the user gets asked to enter a password to decrypt the database. Of course the database never should appear "in clear" (not encrypted) on my harddrive. So is there any possi...

QTrayIcon segfault

Hi all. In my code i tried to connect signal from QTrayIcon object and my form in such way: connect(m_trayIcon, SIGNAL(activated(QSystemTrayIcon::ActivationReason)), this, SLOT(iconActivated(QSystemTrayIcon::ActivationReason))); But i received a segfault on this code. Any ideas? P.S. Sorry for my bad english. ...

How can I use Qt to get html code of the redirected page??

I'm trying to use Qt to download the html code from the following url: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=nucleotide&cmd=search&term=AB100362 this url will re-direct to www.ncbi.nlm.nih.gov/nuccore/27884304 I try to do it by following way, but I cannot get anything. it works for some webpage such as www.google....

Qt How to make a column in QTableWidget read only.

I would like to have one column in QTableWidget NOT editable. I forums have read a lot about some flags bould could not manage to implement. Thanks in advance! ...

how to create multiple selections in text edit box in qt4?

Qt3.3 used to allow for multiple selections in the QTextEdit widget by calling the setSelection() function and specifying a different selection id (selNum) as the last argument in that function. In Qt4, to create a selection, I do it by creating a QTextCursor object and call the setPosition() or movePosition() methods. I have no proble...

How to set QNetworkReply properties to get correct NCBI pages?

I try to get this following url using the downloadURL function as follows: http://www.ncbi.nlm.nih.gov/nuccore/27884304 But the data is not as what we can see through the browser, now I know it's because some correct information (such as browser type) is needed. How can I know what kind of information I need to set, and how can I set ...

QPlainTextEdit segmentation fault

Hi, All! I have some Qt application with QPlainTextEdit in Tab widget. When try to make a pointer on it QPlainTextEdit *w = (QPlainTextEdit*)ui->tabWidget->widget(0) and call a document() method w->document() I get a segfault. But if i call document directly, e.g. ui->mainEdit->document(), then everything works fine. Can anybo...

Qt - How to associate data with QTableWidgetItem?

I want to associate aditional data with each QTableWidgetItem inserted into the table, in order to use that data in future, when it is being clicked on a table item. But that data should not be visible. How can I do that? ...

QxtRPCPeer networked signal/slot example

While being new to Qt, I'm trying to remote control an GUI application with use of QxtRPCPeer. I'm looking for a simple hello world network slider example (one slider in application1 signals setValue() to slider slot in application2), to get the syntax correct. The main goal is similar to a previous question where QxtRPCPeer was recommen...