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sometimes qt was ended forcefully, weird.

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  • Christian EhrlicherC Christian Ehrlicher

    @circle said in sometimes qt was ended forcefully, weird.:

    tried to get the real fullscreen's size in the c'tor

    QScreen doesn't work differently if it is called in the ctor or anywhere else.

    C Offline
    C Offline
    circle
    wrote on last edited by
    #18

    @Christian-Ehrlicher
    more precisely, what i need is the size of centralwidget when it's fullscreen. so i just use the width() and hegith() to obtain those when it's fullscreen.
    i didn't use QScreen, should i?

    @SGaist
    there may be different ways to get the size, but i still don't have a clue why it produce such an error. it seems have nothing to do with the error, and why sometimes it's working, sometimes not.

    JonBJ 1 Reply Last reply
    0
    • Christian EhrlicherC Offline
      Christian EhrlicherC Offline
      Christian Ehrlicher
      Lifetime Qt Champion
      wrote on last edited by
      #19

      @circle said in sometimes qt was ended forcefully, weird.:

      i didn't use QScreen, should i?

      I suggest you to use it so I would say it's worth a try reading the documentation, isn't it?

      Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
      Visit the Qt Academy at https://academy.qt.io/catalog

      1 Reply Last reply
      0
      • C circle

        @Christian-Ehrlicher
        more precisely, what i need is the size of centralwidget when it's fullscreen. so i just use the width() and hegith() to obtain those when it's fullscreen.
        i didn't use QScreen, should i?

        @SGaist
        there may be different ways to get the size, but i still don't have a clue why it produce such an error. it seems have nothing to do with the error, and why sometimes it's working, sometimes not.

        JonBJ Offline
        JonBJ Offline
        JonB
        wrote on last edited by
        #20

        @circle said in sometimes qt was ended forcefully, weird.:

        more precisely, what i need is the size of centralwidget when it's fullscreen.

        Then it doesn't sound like you should be looking at QScreen at all.

        thanks, i tried to get the real fullscreen's size in the c'tor or in the showEvent,

        To get a size of widget (not the full screen, which you shouldn't be interested in) correctly it needs to be shown. If you call it too early, you get rubbish. Constructor is not the place. If in a showEvent(), IIRC you should call the base showEvent() before you try to read the size.

        C 1 Reply Last reply
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        • JonBJ JonB

          @circle said in sometimes qt was ended forcefully, weird.:

          more precisely, what i need is the size of centralwidget when it's fullscreen.

          Then it doesn't sound like you should be looking at QScreen at all.

          thanks, i tried to get the real fullscreen's size in the c'tor or in the showEvent,

          To get a size of widget (not the full screen, which you shouldn't be interested in) correctly it needs to be shown. If you call it too early, you get rubbish. Constructor is not the place. If in a showEvent(), IIRC you should call the base showEvent() before you try to read the size.

          C Offline
          C Offline
          circle
          wrote on last edited by
          #21

          @JonB
          even call the base showEvent() first, i still can't read the right size of the centralwidget.
          anyway, the size is not a problem, the problem is that weird errors reported has nothing to do with the code as far as i am concerned.

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          • Christian EhrlicherC Offline
            Christian EhrlicherC Offline
            Christian Ehrlicher
            Lifetime Qt Champion
            wrote on last edited by
            #22

            @circle said in sometimes qt was ended forcefully, weird.:

            i still can't read the right size of the centralwidget.

            Again: use QScreen to determine the screen size!

            Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
            Visit the Qt Academy at https://academy.qt.io/catalog

            JonBJ 1 Reply Last reply
            0
            • Christian EhrlicherC Christian Ehrlicher

              @circle said in sometimes qt was ended forcefully, weird.:

              i still can't read the right size of the centralwidget.

              Again: use QScreen to determine the screen size!

              JonBJ Offline
              JonBJ Offline
              JonB
              wrote on last edited by
              #23

              @Christian-Ehrlicher
              How will knowing the screen size help this user if he want to know the central widget size?

              1 Reply Last reply
              0
              • Christian EhrlicherC Offline
                Christian EhrlicherC Offline
                Christian Ehrlicher
                Lifetime Qt Champion
                wrote on last edited by
                #24

                @JonB said in sometimes qt was ended forcefully, weird.:

                if he want to know the central widget size?

                my app is fullscreen always

                so...

                Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                Visit the Qt Academy at https://academy.qt.io/catalog

                JonBJ 1 Reply Last reply
                0
                • Christian EhrlicherC Christian Ehrlicher

                  @JonB said in sometimes qt was ended forcefully, weird.:

                  if he want to know the central widget size?

                  my app is fullscreen always

                  so...

                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by
                  #25

                  @Christian-Ehrlicher
                  So? :) The central widget is some widget in the full screen app, but there can be all sorts round the edges. So the widget itself won't be the full screen. I'm thinking like the central widget area in a QMainWindow. I guess you're not?

                  1 Reply Last reply
                  0
                  • Christian EhrlicherC Offline
                    Christian EhrlicherC Offline
                    Christian Ehrlicher
                    Lifetime Qt Champion
                    wrote on last edited by
                    #26

                    @JonB said in sometimes qt was ended forcefully, weird.:

                    I guess you're not?

                    I don't see a need for all the calculation at all - using a proper layout will make all those stuff superfluous.

                    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                    Visit the Qt Academy at https://academy.qt.io/catalog

                    JonBJ 1 Reply Last reply
                    1
                    • Christian EhrlicherC Christian Ehrlicher

                      @JonB said in sometimes qt was ended forcefully, weird.:

                      I guess you're not?

                      I don't see a need for all the calculation at all - using a proper layout will make all those stuff superfluous.

                      JonBJ Offline
                      JonBJ Offline
                      JonB
                      wrote on last edited by JonB
                      #27

                      @Christian-Ehrlicher said in sometimes qt was ended forcefully, weird.:

                      I don't see a need for all the calculation at all - using a proper layout will make all those stuff superfluous.

                      I agree! But it wasn't the question :)

                      1 Reply Last reply
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                      • C Offline
                        C Offline
                        circle
                        wrote on last edited by circle
                        #28

                        @all,
                        thank you so much for your time. sorry i wasn't clear about my requirement. what i care is the centrawidget size when QMainWindow is in fullscreen.

                        again, i am posting the code with the erros,

                        MainWindow::MainWindow(QWidget *parent)
                            : QMainWindow(parent)
                            , ui(new Ui::MainWindow)
                        {
                            ui->setupUi(this);
                            showFullScreen();
                        
                            ui->dockWidget->setWidget(ui->tableWidget);
                        
                            ui->line1->hide();
                        }
                        
                        
                        void MainWindow::resizeEvent(QResizeEvent *event)
                        {
                            QMainWindow::resizeEvent(event);
                        
                            // Your code here.
                            static bool bOnlyOnce = true;
                            if (bOnlyOnce && isVisible())
                            {
                                bOnlyOnce = false;
                                
                                memory allocation, file reading and data initialization
                        
                                QFileInfo fileInfo(QCoreApplication::applicationFilePath()); 
                                if ()
                                    QMessageBox::information(this, "title", QString("%1").arg(fileInfo.size())); //***sometimes crash here ???
                            
                                get the size of centralwidget, prepare drawing environment
                        
                                ui->statusbar->addWidget(ui->lable1, 40); //***sometimes it crash here if i comment out QMessageBox line above*** ???
                            }
                        }
                        

                        now the QMessageBox line would crash sometimes(qtcreator says the process was ended forcefully), and if i comment out this line, the ui->statusbar line sometimes would report "Trying to construct an instance of an invalid type, type id: 1061" and the process was ended forcefully.
                        i haven't found any rules about "sometimes", sometimes it will crash several times continuously when i press CTRL+R, but sometimes the program works fine.
                        And it's working alwasys fine if i press F5 to debug the app.

                        In addition, in the old backup version, it's working always fine. this version just has more functions after the crash point.

                        1 Reply Last reply
                        -3
                        • Christian EhrlicherC Offline
                          Christian EhrlicherC Offline
                          Christian Ehrlicher
                          Lifetime Qt Champion
                          wrote on last edited by Christian Ehrlicher
                          #29

                          As @J-Hilk already told you 4 days ago - don't create an eventloop in a resize event!

                          Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                          Visit the Qt Academy at https://academy.qt.io/catalog

                          C 1 Reply Last reply
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                          • Christian EhrlicherC Christian Ehrlicher

                            As @J-Hilk already told you 4 days ago - don't create an eventloop in a resize event!

                            C Offline
                            C Offline
                            circle
                            wrote on last edited by
                            #30

                            @Christian-Ehrlicher
                            thanks, i am not 100% sure about that answer, but i will try another solution. now the question is, where do i get the size of centralwidget automatically when QMainWindows is in fullscreen (showFullScreen() in c'tor)? i tried showEvent and C'tor but failed to get the right size.

                            JonBJ 1 Reply Last reply
                            0
                            • C circle

                              @Christian-Ehrlicher
                              thanks, i am not 100% sure about that answer, but i will try another solution. now the question is, where do i get the size of centralwidget automatically when QMainWindows is in fullscreen (showFullScreen() in c'tor)? i tried showEvent and C'tor but failed to get the right size.

                              JonBJ Offline
                              JonBJ Offline
                              JonB
                              wrote on last edited by
                              #31

                              @circle
                              I admit I have not tried it but I would have expected it in showEvent() as we discussed earlier. Could you show where you put what code for that?

                              C 1 Reply Last reply
                              0
                              • Christian EhrlicherC Offline
                                Christian EhrlicherC Offline
                                Christian Ehrlicher
                                Lifetime Qt Champion
                                wrote on last edited by
                                #32

                                I still don't understand the need to know the size of a widget at all - your code you showed us doesn't do anything with it. Use layouts...

                                Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                                Visit the Qt Academy at https://academy.qt.io/catalog

                                C 1 Reply Last reply
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                                • JonBJ JonB

                                  @circle
                                  I admit I have not tried it but I would have expected it in showEvent() as we discussed earlier. Could you show where you put what code for that?

                                  C Offline
                                  C Offline
                                  circle
                                  wrote on last edited by circle
                                  #33

                                  @JonB
                                  qDebug to print the line and ui->centralwidget->width()

                                  JonBJ 1 Reply Last reply
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                                  • Christian EhrlicherC Christian Ehrlicher

                                    I still don't understand the need to know the size of a widget at all - your code you showed us doesn't do anything with it. Use layouts...

                                    C Offline
                                    C Offline
                                    circle
                                    wrote on last edited by
                                    #34

                                    @Christian-Ehrlicher
                                    well, i am supposed to do some complicated drawings as the background based on the size of centralwidget, there maybe several different solutions and i never use layouts before. those code was migrated from windows.

                                    1 Reply Last reply
                                    0
                                    • C circle

                                      @JonB
                                      qDebug to print the line and ui->centralwidget->width()

                                      JonBJ Offline
                                      JonBJ Offline
                                      JonB
                                      wrote on last edited by JonB
                                      #35

                                      @circle said in sometimes qt was ended forcefully, weird.:

                                      qDebug to print the line and ui->centralwidget->width()

                                      Can you show just the few lines of code where you do this? What method it's in and where you do it.

                                      C 1 Reply Last reply
                                      0
                                      • Christian EhrlicherC Offline
                                        Christian EhrlicherC Offline
                                        Christian Ehrlicher
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #36

                                        @circle said in sometimes qt was ended forcefully, weird.:

                                        i am supposed to do some complicated drawings as the background

                                        You can't draw on a widget outside the paintEvent()...

                                        Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                                        Visit the Qt Academy at https://academy.qt.io/catalog

                                        C 1 Reply Last reply
                                        1
                                        • JonBJ JonB

                                          @circle said in sometimes qt was ended forcefully, weird.:

                                          qDebug to print the line and ui->centralwidget->width()

                                          Can you show just the few lines of code where you do this? What method it's in and where you do it.

                                          C Offline
                                          C Offline
                                          circle
                                          wrote on last edited by
                                          #37

                                          @JonB said in sometimes qt was ended forcefully, weird.:

                                          @circle said in sometimes qt was ended forcefully, weird.:

                                          qDebug to print the line and ui->centralwidget->width()

                                          Can you show just the few lines of code where you do this? What method it's in and where you do it.

                                          void MainWindow::showEvent(QShowEvent * event)
                                          {
                                              QMainWindow::showEvent(event);
                                              qDebug() << "w: " << ui->centralwidget->width() << "h: " << ui->centralwidget->height();
                                          }
                                          
                                          1 Reply Last reply
                                          1

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