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QDialog don't show widgets, when method show() calling

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  • O oBOXPOH

    @Vinod-Kuntoji said in QDialog don't show widgets, when method show() calling:

    @oBOXPOH ,

    What are you executing?

    Code of the method:
    
    {
        ...
    
        WaitingDialog *dlg = new WaitingDialog;
        dlg->show();
        Sleep(10000);
    }
    
    
    D Offline
    D Offline
    Devopia53
    wrote on last edited by
    #12

    @oBOXPOH

    Never use the Sleep(). This is because the currently executing thread(aka. GUI) is blocking.

    like this:

    WaitingDialog *dlg = new WaitingDialog(this);
    QTimer::singleShot(10000, [=, dlg]{ 
        /* Manage what you want here. */
        dlg->deleteLater(); 
    });
    dlg->setModal(true);
    dlg->show();
    
    O 1 Reply Last reply
    1
    • Vinod KuntojiV Offline
      Vinod KuntojiV Offline
      Vinod Kuntoji
      wrote on last edited by
      #13

      @oBOXPOH ,

      Are you showing dialog inside thread?

      C++, Qt, Qt Quick Developer,
      PthinkS, Bangalore

      O 1 Reply Last reply
      0
      • D Devopia53

        @oBOXPOH

        Never use the Sleep(). This is because the currently executing thread(aka. GUI) is blocking.

        like this:

        WaitingDialog *dlg = new WaitingDialog(this);
        QTimer::singleShot(10000, [=, dlg]{ 
            /* Manage what you want here. */
            dlg->deleteLater(); 
        });
        dlg->setModal(true);
        dlg->show();
        
        O Offline
        O Offline
        oBOXPOH
        wrote on last edited by
        #14

        I used Sleep() as example. If instead of Sleep() I want compute something during showing dialog, what can I do?

        1 Reply Last reply
        0
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #15

          Except that you will block the main thread and thus your dialog will not show until its too late.

          If you have a long computational process running you should consider maybe using QtConcurrent and wire that properly with your GUI.

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          1 Reply Last reply
          2
          • Vinod KuntojiV Vinod Kuntoji

            @oBOXPOH ,

            Are you showing dialog inside thread?

            O Offline
            O Offline
            oBOXPOH
            wrote on last edited by
            #16

            @Vinod-Kuntoji said in QDialog don't show widgets, when method show() calling:

            @oBOXPOH ,

            Are you showing dialog inside thread?

            I show dialog, when something button was clicked. During this dialog some computing task must execute. When this task finish, this dialog must close.

            1 Reply Last reply
            0
            • Vinod KuntojiV Offline
              Vinod KuntojiV Offline
              Vinod Kuntoji
              wrote on last edited by
              #17

              @oBOXPOH ,

              Are you talking about progressbar?

              C++, Qt, Qt Quick Developer,
              PthinkS, Bangalore

              O 1 Reply Last reply
              0
              • Vinod KuntojiV Vinod Kuntoji

                @oBOXPOH ,

                Are you talking about progressbar?

                O Offline
                O Offline
                oBOXPOH
                wrote on last edited by
                #18

                @Vinod-Kuntoji said in QDialog don't show widgets, when method show() calling:

                @oBOXPOH ,

                Are you talking about progressbar?

                Just about some dialog with text without any buttons. If it easier for you, yes, about progressbar.

                mrjjM 1 Reply Last reply
                0
                • O oBOXPOH

                  @Vinod-Kuntoji said in QDialog don't show widgets, when method show() calling:

                  @oBOXPOH ,

                  Are you talking about progressbar?

                  Just about some dialog with text without any buttons. If it easier for you, yes, about progressbar.

                  mrjjM Offline
                  mrjjM Offline
                  mrjj
                  Lifetime Qt Champion
                  wrote on last edited by
                  #19

                  Hi

                  • Just about some dialog with text without any buttons. If it easier for you, yes, about progressbar.

                  Its not so much about being easier.
                  Its a concrete class
                  http://doc.qt.io/qt-5/qprogressbar.html

                  Also
                  WaitingDialog *dlg = new WaitingDialog;
                  dlg->show();
                  Sleep(10000); <<< here u lag all of application. nothing can be drawn and u will first see dialog after 10 secs.

                  Sleep cannot be used to simulate a workload.

                  O 1 Reply Last reply
                  1
                  • mrjjM mrjj

                    Hi

                    • Just about some dialog with text without any buttons. If it easier for you, yes, about progressbar.

                    Its not so much about being easier.
                    Its a concrete class
                    http://doc.qt.io/qt-5/qprogressbar.html

                    Also
                    WaitingDialog *dlg = new WaitingDialog;
                    dlg->show();
                    Sleep(10000); <<< here u lag all of application. nothing can be drawn and u will first see dialog after 10 secs.

                    Sleep cannot be used to simulate a workload.

                    O Offline
                    O Offline
                    oBOXPOH
                    wrote on last edited by
                    #20

                    @mrjj said in QDialog don't show widgets, when method show() calling:

                    Hi

                    • Just about some dialog with text without any buttons. If it easier for you, yes, about progressbar.

                    Its not so much about being easier.
                    Its a concrete class
                    http://doc.qt.io/qt-5/qprogressbar.html

                    Also
                    WaitingDialog *dlg = new WaitingDialog;
                    dlg->show();
                    Sleep(10000); <<< here u lag all of application. nothing can be drawn and u will first see dialog after 10 secs.

                    Sleep cannot be used to simulate a workload.

                    I know! I wrote Sleep() only for example. But even in this case dlg->show() doesn't show content of the dialog, shows only title and window.

                    1 Reply Last reply
                    0
                    • mrjjM Offline
                      mrjjM Offline
                      mrjj
                      Lifetime Qt Champion
                      wrote on last edited by
                      #21

                      @oBOXPOH

                      Ok, but you description of your issue , sounds 100% when a poster loop/sleep the main thread and
                      other windows shows up as empty becuase there is no time to draw the child widgets.

                      dlg->show() doesn't show content of the dialog, shows only title and window.

                      Well do you call a loop or something else after you open the dialog ?

                      Clearly
                      WaitingDialog *dlg = new WaitingDialog;
                      dlg->show();

                      must work and i assume the widget IN the dialog is made with UI file so all should be ok ?

                      There is something you are not telling :)

                      1 Reply Last reply
                      0
                      • Vinod KuntojiV Offline
                        Vinod KuntojiV Offline
                        Vinod Kuntoji
                        wrote on last edited by
                        #22

                        @oBOXPOH ,

                        WaitingDialog *dlg = new WaitingDialog;
                        dlg->exec();

                        connect(dlg,SIGNAL(aborted()),dlg,SLOT(stopDialog()));
                        connect(yourWidget,SIGNAL(executionComplete()),dlg,SLOT(stopDialog()));

                        void WaitingDialog::stopDialog() {
                        this->close();
                        emit aborted();
                        }

                        C++, Qt, Qt Quick Developer,
                        PthinkS, Bangalore

                        O 1 Reply Last reply
                        1
                        • Vinod KuntojiV Vinod Kuntoji

                          @oBOXPOH ,

                          WaitingDialog *dlg = new WaitingDialog;
                          dlg->exec();

                          connect(dlg,SIGNAL(aborted()),dlg,SLOT(stopDialog()));
                          connect(yourWidget,SIGNAL(executionComplete()),dlg,SLOT(stopDialog()));

                          void WaitingDialog::stopDialog() {
                          this->close();
                          emit aborted();
                          }

                          O Offline
                          O Offline
                          oBOXPOH
                          wrote on last edited by
                          #23

                          @Vinod-Kuntoji said in QDialog don't show widgets, when method show() calling:

                          @oBOXPOH ,

                          WaitingDialog *dlg = new WaitingDialog;
                          dlg->exec();

                          connect(dlg,SIGNAL(aborted()),dlg,SLOT(stopDialog()));
                          connect(yourWidget,SIGNAL(executionComplete()),dlg,SLOT(stopDialog()));

                          void WaitingDialog::stopDialog() {
                          this->close();
                          emit aborted();
                          }

                          It seems logical. I'll try. Thanks!

                          1 Reply Last reply
                          0
                          • VRoninV Offline
                            VRoninV Offline
                            VRonin
                            wrote on last edited by VRonin
                            #24

                            I'll say what everybody else is afraid to say. Because this is not the solution Gotham deserves but it's the one it needs right now:
                            just add QApplication::processEvents(); after dlg.show();

                            "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                            ~Napoleon Bonaparte

                            On a crusade to banish setIndexWidget() from the holy land of Qt

                            mrjjM O 2 Replies Last reply
                            3
                            • VRoninV VRonin

                              I'll say what everybody else is afraid to say. Because this is not the solution Gotham deserves but it's the one it needs right now:
                              just add QApplication::processEvents(); after dlg.show();

                              mrjjM Offline
                              mrjjM Offline
                              mrjj
                              Lifetime Qt Champion
                              wrote on last edited by mrjj
                              #25

                              @VRonin
                              hehe first time i seen the evil QApplication::processEvents() served with a batman quote :))

                              1 Reply Last reply
                              0
                              • VRoninV VRonin

                                I'll say what everybody else is afraid to say. Because this is not the solution Gotham deserves but it's the one it needs right now:
                                just add QApplication::processEvents(); after dlg.show();

                                O Offline
                                O Offline
                                oBOXPOH
                                wrote on last edited by
                                #26

                                @VRonin said in QDialog don't show widgets, when method show() calling:

                                I'll say what everybody else is afraid to say. Because this is not the solution Gotham deserves but it's the one it need right now:
                                just add QApplication::processEvents(); after dlg.show();

                                It's working! Thanks a lot! Great!

                                1 Reply Last reply
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