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    • D
      DocDJ last edited by A Former User

      I have a simple window with 2 textedit inputs, a "go" button and a textedit output. When my C++ function handles the "go" button and sends output to the 3rd textedit field, the whole window closes. I never get to see the output. No errors appear. Using Qt4 Designer on Linux (CentOS 6.6). I would like to use this window to continue to accept pairs of inputs, displaying output until the user asks to exit. How can I do that?

      jsulm 1 Reply Last reply Reply Quote 0
      • jsulm
        jsulm Lifetime Qt Champion @DocDJ last edited by

        @DocDJ Sounds like your app crashes. You should debug it to see where exactly it crashes.
        You can post the code of your "go" function here - maybe we can see what is wrong there.

        https://forum.qt.io/topic/113070/qt-code-of-conduct

        1 Reply Last reply Reply Quote 1
        • D
          DocDJ last edited by kshegunov

          Thanks for the superfast reply. Here's the whole program (stripped down to simplest form that fails).

          #include <QtGui>
          #include "djdialog1.h" // note: no "ui_" prefix here
          #include <sstream>
          #include <string>	
          
          int int1, int2, answer;
          djdialog1::djdialog1(QWidget *parent)
              : QDialog(parent)
          	{
          	    setupUi(this); // initialize my form
          	    connect(int1box, SIGNAL(textChanged(const QString &)),
          	        this, SLOT(on_int1box_textChanged()));
          	    connect(int2box, SIGNAL(textChanged(const QString &)),
          	        this, SLOT(on_int1box_textChanged()));
          	  
          	    connect(GoButton, SIGNAL(clicked()), this, SLOT(accept()));
          	}
          void djdialog1::on_GoButton_clicked()
          	{ 
          	    QString qreply;
          	    qreply=QString::number(answer);
          	    answerbox->append(qreply);
          	}
          void djdialog1::on_int1box_textChanged(const QString &arg)
          	{bool ok;
          	int1 = arg.toInt(&ok,10);
          	}
          void djdialog1::on_int2box_textChanged(const QString &arg)
          	{bool ok;
          	int2 = arg.toInt(&ok,10);}
          
          jsulm 1 Reply Last reply Reply Quote 0
          • sneubert
            sneubert last edited by

            at least in the code you posted answer is not initalized and where do you get the pointer to answerbox? shouldn´t this be something like ui->answerbox?

            D 1 Reply Last reply Reply Quote 1
            • jsulm
              jsulm Lifetime Qt Champion @DocDJ last edited by

              @DocDJ To add to @sneubert : did you try to debug? This is the easiest way to find out where the app is crashing.

              https://forum.qt.io/topic/113070/qt-code-of-conduct

              1 Reply Last reply Reply Quote 1
              • D
                DocDJ @sneubert last edited by

                @sneubert Since it compiled without errors or warnings, I wasn't aware it needed a ui->, but I will try it. Thanks for the tip.

                mrjj 1 Reply Last reply Reply Quote 0
                • mrjj
                  mrjj Lifetime Qt Champion @DocDJ last edited by mrjj

                  @DocDJ

                  Hi , you do not need UI but!

                  if you just have
                  QTextEdit *int1box; in djdialog1.h, you need to allocate a real objects before use. This is just a definition of a pointer.

                  // somewhere else
                  int1box = new QTextEdit (this);

                  You use use Designer then all Widgets u place on a form is available via
                  UI->the_name

                  Please notice those are only valid after
                  setupUi(this);

                  D 2 Replies Last reply Reply Quote 1
                  • D
                    DocDJ @mrjj last edited by

                    @jsulm said in program closes too soon:

                    @DocDJ To add to @sneubert : did you try to debug? This is the easiest way to find out where the app is crashing.

                    Not sure how to proceed with debugging this one, as it gives no clue as to a cause. I assumed that creating the int1box, etc in Designer would create the objects in my header file for my c++ code to use.

                    jsulm 2 Replies Last reply Reply Quote 0
                    • jsulm
                      jsulm Lifetime Qt Champion @DocDJ last edited by

                      @DocDJ You said it crashes when your "go" method is called, then put a break point there and debug...

                      https://forum.qt.io/topic/113070/qt-code-of-conduct

                      1 Reply Last reply Reply Quote 0
                      • jsulm
                        jsulm Lifetime Qt Champion @DocDJ last edited by jsulm

                        @DocDJ If you used designer then you should access your UI objects via ui-> , but you don't.
                        If you use designer then you do not add any object pointers to your classes by yourself - this is done for you.
                        Instances are created when you call setupUi() and then you can access them via ui->objName.

                        https://forum.qt.io/topic/113070/qt-code-of-conduct

                        1 Reply Last reply Reply Quote 1
                        • D
                          DocDJ @mrjj last edited by

                          @mrjj said in program closes too soon:

                          @DocDJ

                          Hi , you do not need UI but!

                          if you just have
                          QTextEdit *int1box; in djdialog1.h, you need to allocate a real objects before use. This is just a definition of a pointer.

                          // somewhere else
                          int1box = new QTextEdit (this);

                          You use use Designer then all Widgets u place on a form is available via
                          UI->the_name

                          Please notice those are only valid after
                          setupUi(this);

                          In "setupui, this line: answerbox = new QTextEdit(djdialog1); creates the object. Adding Ui-> in front of answerbox causes an error.

                          1 Reply Last reply Reply Quote 0
                          • D
                            DocDJ last edited by kshegunov

                            It would appear that setupUi is not being called. Here is my main.cpp:

                            #include <QApplication>
                            // following 2 lines are initially here to build the "project"
                            //#include <QDialog>
                            //#include "ui_djdialog1.h"
                            // following line replaces the above 2 lines
                            #include "djdialog1.h"
                            
                            int main(int argc, char *argv[])
                            {
                                QApplication app(argc, argv);
                                /** original code before 1st qmake-qt4 my.pro
                                Ui::djdialog1 ui;  // define an object named "ui" as being a djdialog1 
                                QDialog *mydialog = new QDialog;
                                ui.setupUi(mydialog);
                                */
                                // following line is new (after initial make)
                                djdialog1 *mydialog = new djdialog1;
                            	mydialog->show();
                                return app.exec();
                            }
                            

                            I got this from a Qt tutorial.

                            [Added code tags ~kshegunov]

                            kshegunov 1 Reply Last reply Reply Quote 0
                            • mrjj
                              mrjj Lifetime Qt Champion last edited by

                              Hi
                              It seems you did already call it the normal place ?
                              djdialog1::djdialog1(QWidget *parent)
                              : QDialog(parent)
                              {
                              setupUi(this); // initialize my form <<<<<<<<<<<<<<<<<<<

                              In the ctor.
                              Outside and in main is very unusual :)

                              D 1 Reply Last reply Reply Quote 0
                              • D
                                DocDJ @mrjj last edited by

                                @mrjj The call to setupUi in main was commented-out, so it doesn't happen twice. Maybe I need to do it in main, instead of the dialog. I will have read about how to set a breakpoint in Qt4.

                                mrjj jsulm 2 Replies Last reply Reply Quote 0
                                • mrjj
                                  mrjj Lifetime Qt Champion @DocDJ last edited by

                                  @DocDJ
                                  Well you can create the default desktop widget application (File -> New Project )
                                  and see if that includes the setupUi in mainwindow constructor.

                                  1 Reply Last reply Reply Quote 0
                                  • jsulm
                                    jsulm Lifetime Qt Champion @DocDJ last edited by

                                    @DocDJ Sorry, but this is just completely wrong:

                                    Ui::djdialog1 ui; // define an object named "ui" as being a djdialog1
                                    QDialog *mydialog = new QDialog;
                                    ui.setupUi(mydialog);
                                    

                                    You call setupUi() in the window/dialog you create. That means djdialog1 calls it in its constructor (what you're already doing). main is not the correct place to call setupUI. You really should learn Qt basics first, what you are doing now is just guessing and is wrong.
                                    You can create a default widgets project edit the main window, add a dialog and check the generated code.

                                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                                    kshegunov 1 Reply Last reply Reply Quote 0
                                    • kshegunov
                                      kshegunov Moderators @jsulm last edited by kshegunov

                                      @jsulm said in program closes too soon:

                                      Sorry, but this is just completely wrong:

                                      Actually it's correct. I often initialize the widgets through forms without deriving. The most typical example being:

                                      QMainWindow window;
                                      Ui::MyMainWindowForm ui;
                                      ui.setupUi(&window);
                                      
                                      window.show;
                                      

                                      Notice that the initialized widget is a generic one (as with his code).

                                      PS. And by the way this is commented out.

                                      Kind regards.

                                      Read and abide by the Qt Code of Conduct

                                      jsulm 1 Reply Last reply Reply Quote 0
                                      • kshegunov
                                        kshegunov Moderators @DocDJ last edited by

                                        @DocDJ
                                        Please use the triple backtick to get the code formatted, so people don't get confused and you don't lose any symbols due to forum markup.

                                        Read and abide by the Qt Code of Conduct

                                        1 Reply Last reply Reply Quote 0
                                        • jsulm
                                          jsulm Lifetime Qt Champion @kshegunov last edited by

                                          @kshegunov You're right - it is not wrong, but it is not how it is usually done (at least what I saw so far).
                                          Isn't setupUi() called in the constructor already?

                                          djdialog1::djdialog1(QWidget *parent)
                                              : QDialog(parent)
                                          	{
                                          	    setupUi(this); // initialize my form
                                          

                                          @DocDJ "Adding Ui-> in front of answerbox causes an error." - it is ui-> not Ui->

                                          https://forum.qt.io/topic/113070/qt-code-of-conduct

                                          kshegunov 1 Reply Last reply Reply Quote 0
                                          • kshegunov
                                            kshegunov Moderators @jsulm last edited by kshegunov

                                            @jsulm said in program closes too soon:

                                            but it is not how it is usually done

                                            True, I'm only remarking it's a valid approach. I actually don't advise its usage for beginners.

                                            Isn't setupUi() called in the constructor already?

                                            No, because the object in question is of type QDialog. There's duplication of names - the same name is used for the form and the custom dialog, so I think this is where the confusion stems from.

                                            @DocDJ
                                            Please provide the header file for your class as well. I have a strong suspicion you're deriving both from the dialog and the ui form.

                                            Read and abide by the Qt Code of Conduct

                                            1 Reply Last reply Reply Quote 0
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