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  • Basic compile issue with QT4

    - by Cobus Kruger
    I've been trying to get a dead simple listing from a university textbook to compile with the newest QT SDK for Windows I downloaded last night. After struggling through the regular nonsense (no make.bat, need to manually add environment variables and so on) I am finally at the point where I can build. But only one of the two libraries seem to work. The .pro file I use is dead simple: SUBDIRS += utils \ dataobjects TEMPLATE = subdirs In each of these two subfolders I have the source for a library. Running QMAKE generates a makefile and running Make runs through all the preliminaries and then fails on the g++ call: g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc --out-implib,libdataobjects.a -shared -mthreads -Wl -Wl,--out-implib,c:\Users\Cobus\workspace\lib\libdataobjects.a -o ..\..\lib\dataobjects.dll object_script.dataobjects.Debug -L"c:\Users\Cobus\Portab~1\Qt\2010.02.1\qt\lib" -LC:\Users\Cobus\workspace\lib -lutils -lQtXmld4 -lQtGuid4 -lQtCored4 c:/users/cobus/portab~1/qt/2010.02.1/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../../mingw32/bin/ld.exe: cannot find -lutils The problem seems to be right near the end of the command line, where -lutils is added, indicating that there is a library by the name of utils. While I would have expected to see that, you'll notice the library names after --out include lib in the name, so they become libutils and libdataobjects. I have tried to figure out why this is happening, to no avail. Anyone have an idea what's going on?

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  • QLocalSocket and QLocalServer in browser plugins

    - by kambamsu
    Hi, I have a simple doubt. Does the ipc mechanism in qt work when we use it for developing browser plugins? The reason i ask this is that I can easily get the QLocalSocket and QLocalServer communication to work in a qt application, but when i write a similar piece of code in a browser plugin dll i see that the server does not accept a new connection at all. This is what i do in the server: server = new QLocalServer(this); if( !server->listen("myServer")) { writeFile("Listen failed"); } connect(server, SIGNAL(newConnection()), this, SLOT(handleConn()),Qt::QueuedConnection); and this is what i do in the client: client = new QLocalSocket(this); client->abort(); QObject::connect(client,SIGNAL(connected()),this,SLOT(connClient()),Qt::QueuedConnection); client->connectToServer("myServer"); after i call connectToServer, my client emits the connected() signal and the connClient() slot is called. But, on the server side, there is no signal emitted. It doesn't seem to be receiving any connection at all. Any help would be appreciated. Thanks

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  • Carbon, LSUIElement, and showing a window

    - by James Turner
    I have a Carbon LSUIElement application, which runs in the background (possibly with an icon in the menubar, depending on a pref) and occasionally needs to show a dialog to the user - sometimes in response to a user event, but sometimes in response to a background task failing or similar. (I'm using Qt 4.5, so the application is Carbon based; With Qt 4.6 things will be Cocoa based, but it sounds as if the problem may exist there too). The problem is that when I open a window, and show it, it doesn't get brought to the front. I assume this is an artefect of being an LSUIElement app. Qt uses SelectWindow in Carbon, and [makeKeyAndOrderFront] in Cocoa, to bring a window (and the app) to the front. To work around the problem, I tried going direct to the window server: (the first few steps are to get the WindowID, this will be simpler with Qt-Cocoa, since I can use NSWindow:nativeWindow) WindowRef ref = HIViewGetWindow((HIViewRef) aWidget->winId()); CGSWindow wid = GetNativeWindowFromWindowRef(ref); CGSConnection cid =_CGSDefaultConnection(); CGSOrderWindow(cid, wid, 1 /* above everything */, 0 /* NULL */); This works, sort of - the window comes to the front, but it's not highlighted or keyboard focused. Are there additional steps to fix those issues, or is there a simpler solution to the whole problem?

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  • How can i iterate through QListWidget items and work with each item?

    - by Hossein
    In CSharp its as simple as writting : listBox1.Items.Add("Hello"); listBox1.Items.Add("There"); foreach (string item in listBox1.Items ) { MessageBox.Show(item.ToString()); } and i can easily add different objects to a list box and then retrieve them using foreach. I tried the same approach in Qt 4.8.2 but it seems they are different.though they look very similar at first.I found that Qt supports foreach so i went on and tried something like : foreach(QListWidgetItem& item,ui->listWidget->items()) { item.setTextColor(QColor::blue()); } which failed clearly.It says the items() needs a parameter which confuses me.I am trying to iterate through the ListBox itself, so what does this mean? I tried passing the ListBox object as the parameter itself this again failed too: foreach(QListWidgetItem& item,ui->listWidget->items(ui->listWidget)) { item.setTextColor(QColor::blue()); } So here are my questions: How can I iterate through a QListWidget items in Qt? Can i store objects as items in QListWidgets like C#? How can i convert an object in QListWidgets to string(C#s ToString counter part in Qt) ? (suppose i want to use a QMessagBox instead of that setTextColor and want to print out all string items in the QlistWidget.)

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  • A generic C++ library that provides QtConcurrent functionality?

    - by Lucas
    QtConcurrent is awesome. I'll let the Qt docs speak for themselves: QtConcurrent includes functional programming style APIs for parallel list processing, including a MapReduce and FilterReduce implementation for shared-memory (non-distributed) systems, and classes for managing asynchronous computations in GUI applications. For instance, you give QtConcurrent::map() an iterable sequence and a function that accepts items of the type stored in the sequence, and that function is applied to all the items in the collection. This is done in a multi-threaded manner, with a thread pool equal to the number of logical CPU's on the system. There are plenty of other function in QtConcurrent, like filter(), filteredReduced() etc. The standard CompSci map/reduce functions and the like. I'm totally in love with this, but I'm starting work on an OSS project that will not be using the Qt framework. It's a library, and I don't want to force others to depend on such a large framework like Qt. I'm trying to keep external dependencies to a minimum (it's the decent thing to do). I'm looking for a generic C++ framework that provides me with the same/similar high-level primitives that QtConcurrent does. AFAIK boost has nothing like this (I may be wrong though). boost::thread is very low-level compared to what I'm looking for. I know C# has something very similar with their Parallel Extensions so I know this isn't a Qt-only idea. What do you suggest I use?

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  • Cannot press QPushButton in a simple program

    - by shadyabhi
    Basically, I want a simple pushButton with a colorful text which when pressed exits the application. Why cant I press PushButton in this simple program. I am using QT 4.6 on Arch x86_64. #include <QtGui/QApplication> #include <QLabel> #include <QPushButton> #include<QtGui> int main(int argc, char *argv[]) { QApplication a(argc, argv); QMainWindow *Main=new QMainWindow; QPushButton *button = new QPushButton(Main); QLabel *label = new QLabel(Main); label->setText("<h2><i>Hello</i> ""<font color=red>Qt!</font></h2>"); label->setVisible(true); QObject::connect(button, SIGNAL(clicked()),label, SLOT(clear())); label->setAlignment(Qt::AlignCenter|Qt::AlignVCenter); label->setWindowTitle("HelloWorld Test Program"); Main->show(); return a.exec(); }

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  • Architecture for Qt SIGNAL with subclass-specific, templated argument type

    - by Barry Wark
    I am developing a scientific data acquisition application using Qt. Since I'm not a deep expert in Qt, I'd like some architecture advise from the community on the following problem: The application supports several hardware acquisition interfaces but I would like to provide an common API on top of those interfaces. Each interface has a sample data type and a units for its data. So I'm representing a vector of samples from each device as a std::vector of Boost.Units quantities (i.e. std::vector<boost::units::quantity<unit,sample_type> >). I'd like to use a multi-cast style architecture, where each data source broadcasts newly received data to 1 or more interested parties. Qt's Signal/Slot mechanism is an obvious fit for this style. So, I'd like each data source to emit a signal like typedef std::vector<boost::units::quantity<unit,sample_type> > SampleVector signals: void samplesAcquired(SampleVector sampleVector); for the unit and sample_type appropriate for that device. Since tempalted QObject subclasses aren't supported by the meta-object compiler, there doesn't seem to be a way to have a (tempalted) base class for all data sources which defines the samplesAcquired Signal. In other words, the following won't work: template<T,U> //sample type and units class DataSource : public QObject { Q_OBJECT ... public: typedef std::vector<boost::units::quantity<U,T> > SampleVector signals: void samplesAcquired(SampleVector sampleVector); }; The best option I've been able to come up with is a two-layered approach: template<T,U> //sample type and units class IAcquiredSamples { public: typedef std::vector<boost::units::quantity<U,T> > SampleVector virtual shared_ptr<SampleVector> acquiredData(TimeStamp ts, unsigned long nsamples); }; class DataSource : public QObject { ... signals: void samplesAcquired(TimeStamp ts, unsigned long nsamples); }; The samplesAcquired signal now gives a timestamp and number of samples for the acquisition and clients must use the IAcquiredSamples API to retrieve those samples. Obviously data sources must subclass both DataSource and IAcquiredSamples. The disadvantage of this approach appears to be a loss of simplicity in the API... it would be much nicer if clients could get the acquired samples in the Slot connected. Being able to use Qt's queued connections would also make threading issues easier instead of having to manage them in the acquiredData method within each subclass. One other possibility, is to use a QVariant argument. This necessarily puts the onus on subclass to register their particular sample vector type with Q_REGISTER_METATYPE/qRegisterMetaType. Not really a big deal. Clients of the base class however, will have no way of knowing what type the QVariant value type is, unless a tag struct is also passed with the signal. I consider this solution at least as convoluted as the one above, as it forces clients of the abstract base class API to deal with some of the gnarlier aspects of type system. So, is there a way to achieve the templated signal parameter? Is there a better architecture than the one I've proposed?

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  • How to generate .sln/.vcproj using qmake

    - by stas
    Hi! I have main.cpp in c:\test folder and do the following: qmake -project qmake -tp vc test.pro The answer is: WARNING: Unable to generate output for: C:/test//Makefile.Debug [TEMPLATE vcapp] WARNING: Unable to generate output for: C:/test//Makefile.Release [TEMPLATE vcapp] But, I don't need make files. I need .vcproj! Environment: Windows XP Pro SP3, MSVC 7.1 and 8.0. Qt is installed in C:\Qt\2010.02 (LGPL version). Commands are run from Qt Command Prompt. What's wrong with it? How to generate .sln/.vcproj? May I generate them for MSVC 7.1 and 8.0?

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  • Building using CMake-GUI

    - by goodwince
    I am trying to build Marble on Windows (XP) and have been extremely unsuccessful. Following the instructions written here. I am wanting to build it as QT only. Configuration of the build tree fails. I am using the cmake-gui since I have never tried to compile using cmake it's possible it could be something in there. I found a similar issue; however, they compiled QT using Visual Studio and I am using QT Creator which compiles with MinGW so I need to compile in a different manner. CMake-GUI configuration source-code: MyDirectory/Marble where to build: MyDirectory/Build I also added an entry as.. DQTONLY and it's value set to ON

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  • Very slow remote page load performance in QtWebKit (Windows)

    - by Gil
    I get very slow load times on QtWebKit on Windows 7, through ADSL. I am using the Qt Demo Browser, on a Core2 Quad, 64 bit Windows 7, 4GB ram, 2gb processor. through a VPN. Simplest example: google search page takes ~18 seconds to load, compared to 2.5 on Chrome (cash cleared). On larger pages, with scripts etc. it is worse. I tried Qt 4.6 and also the Qt 4.7 beta, but don't see any difference. I see the same results with Arora browser. Are there any settings, or patches that can be applied to fix this? Thanks

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  • Why is QProcess converting the '=' in my arguments to spaces

    - by dagorym
    I've run into a weird error with a Qt program running on Windows. The program uses QProcess to spawn a child process wit two arguments. The program and arguments passed to the QProcess::start() method are of the form: "batchfile.bat" "--option1=some_value" "--option2=some_other_value\with_a\path" For some reason by the time those options get to the batchfile for processing the equals signs have been converted to spaces and it now looks like: "batchfile.bat" "--option1 some_value" "--option2 some_other_value\with_a\path" because of this, the processing fails. Any ideas what could be causing the equal signs to be replaced by spaces? I'm using the mingw build of the QT 4.6.3 framework found on the Qt download page.

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  • Any really modern, good-looking desktop apps that are developed with PyQt/PySide?

    - by Edwin
    Hi, I have started using Python for web development recently, it's kinda cool; I have seen programs that are developed in QT/C++, which is good enough in terms of esthetics; I have just noticed the new PySide project (which brings LGPL Qt license to Python and it doesn't support Windows yet). In view of the above, I see the possibility of using Python + PyQt/PySide to develop cross platform apps in the future :) but I have several doubts right now: Can PyQty/PySide be used to develop really complex/modern UI? Can somebody give me some points to have a look at some nice-looking screenshots of apps that are developed in Python+QT? What about the performance? Thanks in advance!

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  • will destroyed() be emitted if the constructor of a class derived from QObject throws?

    - by PorkyBrain
    Ive seen Qt GUI syntax like the following all over the place: myDialog::myDialog(QWidget *parent, Qt::WFlags flags):QDialog(parent, flags) { QPushButton *button = new QPushButton("&Download", this); QVBoxLayout *layout = new QVBoxLayout(this); //something that can throw here layout ->addWidget(button ); setLayout(layout); } I've always wondered if this can leak in the event of an exception because the "this" I'm giving as a parent to button and layout is not fully constructed so it might not destroy its children. I tried it out in MSVC2010 Qt4.8.3 and it looks like as soon as the base QObject class is fully created (which is done first of course) it is ok to pass "this" to other objects in the constructor, they will destroyed correctly. I haven't found the spot in the Qt docs guaranteeing this though, can someone point me to it so I have assurance that this will not change in the future?

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  • QT: I've inherited from QTreeView. I've inherited from QStandardItem. How do i Style the items?

    - by San Jacinto
    My Google skills must be failing me today. I've inherited from QTreeView to create a TreeView that stores a QStandardItemModel instead of a QAbstractItemModel. I have also inherited from QStandardItem to create a class to store my data in an item as is necessary. I've successfully inserted my derived QStandardItem into my derived QTreeView's QStandardItemModel. Now the trouble is, I can't figure out how to style it. I know that QTreeView has a setStyleSheet(QString) member, but I can't seem to get it working. It may be as simple as I'm not styling the correct attribute. Any pointers would be appreciated. Thanks. For clarity, here are my class defs. class SurveyTreeItem : public QStandardItem { public: SurveyTreeItem(); SurveyTreeItem( const QString & text ); ~SurveyTreeItem(); }; class StandardItemModelTreeView : public QTreeView { public: StandardItemModelTreeView(QWidget* parent = 0); ~StandardItemModelTreeView(); QStandardItemModel* getStandardItemModel(); }; I've tried the following StyleSheets: StandardTreeView::Item { font: 87 12pt 'Arial Black'; } StandardTreeView::QStandardItem { font: 87 12pt 'Arial Black'; } QTreeView::QStandardItem { font: 87 12pt 'Arial Black'; } QTreeView::Item { font: 87 12pt 'Arial Black'; } QTreeView::SurveyTreeItem { font: 87 12pt 'Arial Black'; } StandardTreeView::SurveyTreeItem { font: 87 12pt 'Arial Black'; }

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  • Normal C++ code in Qt doesnt build and run

    - by Nick
    Hello. I am using Qt under linux, if it matters. I ran successfully under Geany (a simple c++ compiler) the following: //my first program in C++ Hello World! include using namespace std; int main () {cout << "Hello World!"; return 0;} I opened Qt source file and copied the exact same code and i can't build or run. Thank you for your responses to this simple problem.

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  • Program exit code -SomeNumber

    - by JohnnyLongPants
    i made a program using Qt for Symbian, its all working very well ... However, it always exits with a status code -10737something when i close the program i think the problem is in the deconstructer, maybe some memory leaks ... any suggestion on how to solve this problem, or to find the error using Qt Creator? thanks

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  • QListView how to add column ?

    - by Samir
    How can I add columns to QListView control. Found a method addColumn while seardhing, but in my Qt Creator 1.2.1 based on Qt 4.5.2(32 bit) QListView doesn't have such method at all !!! So how would I add columns ? Say I have 3 columns then what is the code to add a row ?

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  • Container item implementation

    - by onurozcelik
    Hi, I am working in Train Traffic Controller software project. My responsibility in this project is to develop the visual railroad GUI. We are implementing the project with Qt. By now I am using QGraphicsLinearLayout to hold my items. I am using the layout because I do not want to calculate coordinates of each item. So far I wrote item classes to add the layout. For instance SwitchItem class symbolizes railroad switch in real world. Each item class is responsible for its own painting and events. So far so good. Now I need a composite item that can contain two or more item. This class is going to be responsible for painting the items contained in it. I need this class because I have to put two or more items inside same layout cell. If I don' t put them in same cell I can' t use layout. See the image below. BlockSegmentItem and SignalItem inside same cell. Here is my compositeitem implementation. #include "compositeitem.h" CompositeItem::CompositeItem(QString id,QList<FieldItem *> _children) { children = _children; } CompositeItem::~CompositeItem() { } QRectF CompositeItem::boundingRect() const { FieldItem *child; QRectF rect(0,0,0,0); foreach(child,children) { rect = rect.united(child->boundingRect()); } return rect; } void CompositeItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget ) { FieldItem *child; foreach(child,children) { child->paint(painter,option,widget); } } QSizeF CompositeItem::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const { QSizeF itsSize(0,0); FieldItem *child; foreach(child,children) { // if its size empty set first child size to itsSize if(itsSize.isEmpty()) itsSize = child->sizeHint(Qt::PreferredSize); else { QSizeF childSize = child->sizeHint(Qt::PreferredSize); if(itsSize.width() < childSize.width()) itsSize.setWidth(childSize.width()); itsSize.setHeight(itsSize.height() + childSize.height()); } } return itsSize; } void CompositeItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event) { qDebug()<<"Test"; } This code works good with painting but when it comes to item events it is problematic. QGraphicsScene treats the composite item like a single item which is right for layout but not for events. Because each item has its own event implementation.(e.g. SignalItem has its special context menu event.) I have to handle item events seperately. Also I need a composite item implementation for the layout. How can I overcome this dilemma?

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  • win32:libs undefined reference

    - by hector
    I want to link a .lib in my Qt project and I get an error about an undefined reference to vhtIOConn::getDefault(vhtIOConn::DeviceType). I have already added the following specifications to the .pro file: ###################################################################### # Automatically generated by qmake (2.01a) vie 28. ago 12:48:10 2009 ###################################################################### TARGET = DEPENDPATH += . INCLUDEPATH += . LIBS += "C:\agregar\VirtualHandCore.lib" LIBS += "C:\agregar\VirtualHandDevice.lib" LIBS += "C:\agregar\VirtualHandRegistry.lib" # Input HEADERS += "C:/Documents and Settings/halvarado/Mis documentos/respaldos de Qt/Development/include/vhandtk/vhtBase.h" SOURCES += main.cpp What should I do?

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  • How to compile a C project with more than one main function?

    - by Daziplqa
    Hi folks, I am new to C, and now read some textbook and going to apply its examples. The problem is, whenever I creates a new project and try to put more than one file that contains a main function, the linker (as I thougt0 explains saying: /home/mohammed/tmp/abcd/main.c:4: multiple definition of `main' (BTW, I used many IDEs, MonoDevelop, QT creator, VS2010, Codebloks, ...) I am currently uses QT Creator, It seems to be a very nice IDE. So, there's not a workaround to solve such problem??

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