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Search found 4081 results on 164 pages for 'qt mfc migration'.

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  • Qt Graphics Scene mouse event propagation

    - by Olorin
    hello i'm learning qt and i'm doing the folowing to add some widgets to a graphics scene void MainWindow::addWidgets(QList<QWidget *> &list, int code) { if(code == CODE_INFO) { QWidget *layoutWidget = new QWidget(); QVBoxLayout *layout = new QVBoxLayout(); foreach(QWidget *w, list) { layout->addWidget(w); this->connect(((ProductInfo*)w), SIGNAL(productClicked()), this, SLOT(getProductDetails())); } layoutWidget->setLayout(layout); this->scene->addWidget(layoutWidget); } } my ProductInfo class processes mouse release and emits a signal void ProductInfo::mouseReleaseEvent(QMouseEvent *e) { QWidget::mouseReleaseEvent(e); emit productClicked(); } the problem is after adding the widgets to the scene they no longer get the mouse release event and don't emit productClicked signal but if i add them to the main window(not to the scene) they work as expected. What am i doing wrong?

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  • Memory management in Qt?

    - by Martin
    I'm quite new to Qt and am wondering on some basic stuff with memory management and the life of objects. When do I need to delete / destroy my objects? Is any of this handled automatically? In the example below, which of the objects I create do I need to delete? What happens to the instance variable myOtherClass when myClass is destroyed? What happens if I don't delete / destroy my objects at all, will that be a problem to memory? in MyClass.h: class MyClass { public: MyClass(); ~MyClass(); MyOtherClass *myOtherClass; }; in MyClass.cpp: MyClass::MyClass() { myOtherClass = new MyOtherClass(); MyOtherClass myOtherClass2; QString myString = "Hello"; } As you can see this is quite newbie-easy stuff but where can I learn about this in an easy way? Thanks really much

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  • Overlapping labels in Qt fridge magnets example

    - by bullettime
    I want to modify the fridge magnets example provided with Qt in a way that when I drag a label and drop it over another, it will push the label beneath the dragged label to the side, so they will never overlap one another. I've seen how collision is detected in the colliding mice example, where it uses a QGraphicsScene to draw the QGraphicsItem mice on, and scene()-collidingItems(this) to see which mice are colliding. The problem is that the fridge magnets example uses a class that inherits QWidget in place of QGraphicsScene, so there's no collidingItems() method to check when we have a collision. How do I go about doing that?

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  • Determine signals connected to a given slot in Qt

    - by Cody Brocious
    I've injected myself into a Qt application, and I'm attempting to figure out what signals a given slot is connected to, but can't find any information on doing this. Is there a mechanism for doing this out of the box? If so, is this exposed to QtScript? (If not, I can wrap it easily enough.) If there is no such mechanism, what would be the best way to add it? I cannot manipulate the existing application outside of simple hooking, but I could hook QObject::connect and store the connections myself, just not sure if that's the best way to go about it.

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  • how to implement OOP using QT

    - by kaycee
    hi, this is a simple OOP QT question. my app consists of main window (QMainWindow) and a table (QTableWidget). in the main window i have arguments and variables which i would like to pass to the table class, and to access methods in main widnow class from the table class, how should i do it ? mainwindow.h class MainWindow : public QMainWindow { Q_OBJECT private: int a; int b; Spreadsheet *spreadsheet; public: void set_a(int); void set_b(int); spreadsheet.h class Spreadsheet : public QTableWidget { Q_OBJECT public: Spreadsheet(QWidget *parent = 0); atm i define Spreadsheet like this: spreadsheet = new Spreadsheet(this); and i'd like to access set_a() from spreadsheet.cpp...

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  • Function matching in Qt

    - by Alexander
    Hello, I have some trouble with Qt. I have a class 'Core' class Core { public: static QString get_file_content(QString filename); static void setMainwindow(MainWindow *w); private: static MainWindow *main_window; }; and class 'MainWindow' in namespace Ui: namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); ~MainWindow(); private: Ui::MainWindow *ui; }; In MainWindow constructor I make MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); Core::setMainwindow(this); } and gets error mainwindow.cpp:8: error: no matching function for call to 'Core::setMainwindow(MainWindow* const)' Of cource, i include core.h with declaration of 'Core' class. That's occurs only on setMainwindow method. So the questions is - why Core class method setMainwindow() is invisible in MainWindow class?

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  • Block All Keyboard Input in a Linux Application (Using Qt or Mono)

    - by Evans
    Hi, I'm working on a online quiz client where we use a dedicated custom-made linux distro which contains only the quiz client software along with text editors and other utility software. When the user has started the quiz, I want to prevent him/her from minimizing the window/closing it/switching to the desktop or other windows. The quizzes can be attempted using only the mouse, so I need the keyboard to be completed disabled for the period of the quiz. How could I do this, using Qt or Mono? I'm ready to use any low-level libraries/drivers, if required. Thanks Evans

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  • Architectural decision : QT or Eclipse Platform ?

    - by umanga
    We are in the process of designing a tool to be used with HDEM(High Definition Electron Microscope).We get stacks of 2D images from HDEM and first step is 'detecting borders' on the sections.After detecting edges of 2D slices ,next step is construct the 3D model using these 2D slices. This 'border detecting' algorithm(s) is/are implemented by one of professor and he has used and suggests to use C.(to gain high performance and probably will parallelise in future) We have to develop comprehensive UI ,3D viewer ,2D editor...etc and use this algorithm. Application should support usual features like project save/open.Undo,Redo...etc Our technology decisions are: A) Build entire platform from the scratch using QT. B) Use Eclipse Platform Our concerns are, if we choose A) we can easily integrate the 'border detecting' algorithm(s) because the development environment is C/C++ But we have to implement the basic features from the scratch. If we choose B) we get basic features from the Eclipse platform , but integrating C libraries going to be a tedious task. Any suggestions on this?

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  • How to create a new File in Qt

    - by GG
    Hello friends, I am a Qt beginner and just got stuck with the problem. I am looking for a file SomePath/NewDirectoryA/NewFile.kml ( NewFile.kml will be the only file in NewDirectoryA, having this directory just to maintain semantics in the project ). If SomePath/NewDirectoryA/NewFile.kml exists then I will use it in my code and If it doesn't exist then I have to create it. If this File doesn't exist then this directory also doesn't exist in SomePath. So If only I have to create a file I can use QFile and open it in ReadWrite or WriteOnly mode. But the problem is I have to create the file with the directory itself. I tried with QFile with file name SomePath/NewDirectoryA/NewFile.kml but it didn't worked. Please suggest me a way in which I can create a new file( NewFile.kml ) in a new directory( NewDirectorA ) at a given location( SomePath ).

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  • Can Qt's QWebView display programatically generated XML?

    - by Dan Ellis
    Using Qt 4.6, I can dynamically add to an HTML page like this: ui->webView->page()->mainFrame()->documentElement().findFirst("body").appendInside("<i>some text</i>\n"); However, if I QWebView::load() an XML file, it displays it with the correct CSS styling (from an processing instruction), but doesn't show any changes when I do something like: ui->webView->page()->mainFrame()->documentElement().findFirst("lines").appendInside("<line>hello</line>\n"); Why is it treating them differently, and is there a way to modify an XML document in the same way I can an HTML one?

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  • Qt QTextEdit Qt4.2 Valid HTML String

    - by Matthew Hoggan
    I am trying to generate the correct HTML to render to a QTextEdit Using Qt 4.2 on RHEL 5.3. So far my algorithm generates the following html. I am not an expert web developer, but to me this string seems valid. 319:14:27:22: <font color="rgb(255,0,0)" bgcolor="rgb(255,0,0)">Message</font><br> What needs to change to get the colours to render. Currently it just renders as black text on a white background.

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  • Qt for Symbian - Detecting touch/non-touch devices...

    - by Nikos
    I'm porting a game for Symbian which supports both a touch & non-touch UI. I need to be able to tell if the device has a touch screen on start-up so I can enable the appropriate mode. After googling for hours and going though the Qt Docs I found QSysInfo but this merely provides the version of the Symbian device. Is there a way to get the actual capabilities of the device? There must be a way to tell if the device has a touch screen...! I'm using the latest QtCreator with the NokiaSDK. Thank you in advance, Nikos.

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  • using sqlite database with qt

    - by Lakshan Perera
    here is my code, it dont seems enything wrong, QSqlDatabase db=QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName("thedata.sqlite"); db.open(); QSqlQuery quary; quary.prepare("SELECT lastname FROM people where firstname='?' "); quary.bindValue(0,lineEdit->text()); bool x=quary.exec(); if(x){ //...... } else { QSqlError err; err=quary.lastError(); QMessageBox::about(this,"error",err.text() ); } when the program is working always it gives the error parameter count mismatch im using qt 4.8 and its own headers for using sqlite. I would be very thankful for eny advice, though I searched in google i see many posts in this issue but nothing helped me. thank you.

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  • Qt grabWindow coordinates shifted from GetCursorPos and GetWindowRect

    - by user1391
    In Qt, when I use the QPixmap::grabWindow(hwnd,x,y,h,w) function, the coordinates are shifted slightly, when compared to the coordinates using the windows api functions GetCursorPos and GetWindowRect. i.e. (0,0) from the point of view of GetCursorPos and GetWindowRect is at the very top left of the toolbar at the top of the window. But (0,0) for QPixmap::grabWindow is more "inside" (i.e. ignoring the window frame). How can I make these 2 coordinates consistent? Especially since the user might have different thicknesses for the window frame?

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  • QT: QPainter + GDI in the same widget?

    - by shoosh
    I'm trying to use the method described here to use a QPainter and GDI calls on the same widget. Unfortunately this tutorial seem to have been written on an earlier version of QT and now it does not work. I set the WA_PaintOnScreen flag and reimplement paintEngine() to return NULL. Then on the paintEvent() I create a QPainter, use it and then use some GDI calls to paint a bitmap. The GDI calls work fine but the QPainter does nothing. I get the following error on the console: QPainter::begin: Paint device returned engine == 0, type: 1 Is this simply not supported anymore? how can I do it? I've also tried creating an additional widget on top of the GDI-painting widget but that didn't go well as well since the top widget appears black and blocks the GDI widget.

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  • use qt and django to create desktop apps

    - by sandra
    Hi guys, I had this idea of creating desktop apps using django. The principe being: - Write the django app, and use something like cherrypy to serve it. - Write a Qt app in C++ to access it and this by using QtWebview (webkit) I'd like to "bundle" this in a single app. The lighter, the better :) So here are my questions and if you have better ideas and suggestions, please share them :) Is it possible to serve a django app with a c++ one? (a c++ server embedding python)? anyone did this before? Do you have some articles, blog posts? Thanks a lot!

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  • Windows Power State change event notification in Qt

    - by Surjya Narayana Padhi
    Hi Geeks, I developing a GUI in QT where I have to show the battery status icon. To get the system power status, I am using the windows API. But to show status anytime , do i need to use a thread to continuously read and display the power status? I am thinking of using event handler. But not sure how to implement. I am thinking that for just one status icon I will run a thread. Anybody has any better suggestion, please share.

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  • Implementing implicitly shared classes outside of Qt

    - by Timothy Baldridge
    I'm familiar with the way Qt uses D-pointers for managing data. How do I do this in my code? I tried this method: 1) move all data into a struct 2) add a QAtomicInt to the struct 3) implement a = operator and change my constructor/deconstructor to check-up on the reference count. The issue is, when I go to do a shallow copy of the object, I get an error about QObject declaring = as private. How then do I accomplish this? Here's an example of my copy operator: HttpRequest & HttpRequest::operator=(const HttpRequest &other) { other.d->ref.ref(); if (!d->ref.deref()) delete d; d = other.d; return *this; } Am I going about this the wrong way?

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  • QT Modeless dialog window dos'nt response to the move command

    - by user63898
    Hello all im using Modeless dialog in my application , and when i try to use the Modeless dialog move command from the MainWindow the Modeless dialog didint even show up,why ? (by the way if i remove the move command every thing works and i can see the dialog when called, i try to move it to the systray era. here somecode: M odelessDialog* ModelessDialog= new ModelessDialog(this); ModelessDialog->setModal(false); ModelessDialog->setAttribute(Qt::WA_DeleteOnClose); int topLeft_x = m_SystrayReq.topLeft().x(); int topLeft_y = m_SystrayReq.topLeft().y(); // the valus of x & y are just fine . ModelessDialog->move(topLeft_x,topLeft_y); ModelessDialog->show();

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  • Getting values from pro files in Qt

    - by user249490
    Hi, I am using Qt 4.5 in Windows XP. My pro file has the variable VERSION = 1.0. Now i need to read this variable and get its value (1.0) from the source code. So that I don't have to maintain another variable for version inside my source code. I just read from the pro file and update it. So that the value remains consistent all over my project. Is it possible? Any pointers regarding this are welcome..

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  • Qt: default value of variable in class

    - by Martin
    When creating my own class in Qt I would like my variables in the class to have a standard/default value if I haven't set them to anything. It would be perfect if this was possible to set in the h-file so I don't have to do it in each instance method of my class. You can see what I want to do in the code below. In the example myBool would have the value of false and myInt the value of 0 when the object have been created. Is this possible at all? In myclass.h: class MyClass { Q_OBJECT public: MyClass(); ~MyClass(); bool myBool = false; //I want to set myBool and myInt to a default/standard value int myInt = 0; };

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  • Qt and finding partial matches in a QList

    - by ExpatEgghead
    I have a struct viz: struct NameKey { std::string fullName; std::string probeName; std::string format; std::string source; } which are held in a QList: QList<NameKey> keyList; what I need to do is find an occurence in keyList of a partial match where the search is for a NameKey that only has two members filled. All the keyList entries are full NameKey's. My current implementation is , well, boring in the extreme with too many if's and conditions. So, If I have a DataKey with a fullName and a format I need to find all the occurences in keyList which match. Any useful Qt/boost things available?

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  • Qt layout problem.

    - by Lukasz Lew
    I have a following Qt code: QVBoxLayout* box = new QVBoxLayout; label = new QLabel(); // will be set later dynamically box->addWidget (label); Text in label will be set later. The problem is that when label resizes, it resizes QVBoxLayout, and it resizes other neighboring widgets. I don't want to make a label or layout fixed width. Because I want them to resize with a whole window. Is it possible to tell a widget to take all the place that it has in a layout, but not more?

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  • Qt Creator Debugging

    - by CJ
    I'm using QT Creator on 3 platforms to create platform independent software. However, I'm getting a segmentation fault with the exact same code in Windows only. That doesn't sound so bad because I can use the debugger. Except, no matter how many breakpoints I set or where I set them, they are ignored by the debugger. I am 100% sure that my control flow is going through the breakpoint but not breaking the flow. Any thoughts? How can that happen?

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  • Qt/C++ regular expression library with unicode property support

    - by Dave
    I'm converting an application from the .Net framework to Qt using C++. The application makes extensive use of regular expression unicode properties, i.e. \p{L}, \p{M}, etc. I've just discovered that the QRegExp class lacks support for this among other things (lookbehinds, etc.) Can anyone recommend a C++ regular expression library that: Supports unicode properties Is unicode-aware in other respects (i.e. \w matches more than ASCII word characters) As a bonus, supports lookbehinds. Please don't point me to the wikipedia article; I don't trust it. That article says that QRegExp supports unicode properties. Unless I'm really doing something wrong, it doesn't. I'm looking for someone actually using unicode properties with a regex library in a project.

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