Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. QWidget::windowRole() use as storage for small textual data
Forum Updated to NodeBB v4.3 + New Features

QWidget::windowRole() use as storage for small textual data

Scheduled Pinned Locked Moved Solved General and Desktop
33 Posts 4 Posters 5.1k Views 2 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • SGaistS SGaist

    Hi,

    You can use a dynamic property.

    Please_Help_me_DP Offline
    Please_Help_me_DP Offline
    Please_Help_me_D
    wrote on last edited by
    #3

    @SGaist thank you! I think this is what I was looking for :)

    1 Reply Last reply
    0
    • SGaistS SGaist

      Hi,

      You can use a dynamic property.

      Please_Help_me_DP Offline
      Please_Help_me_DP Offline
      Please_Help_me_D
      wrote on last edited by
      #4

      @SGaist I'm trying to use bool QObject::setProperty(const char *name, const QVariant &value)
      In my MainWindow I call MyClass where I create some objects and set for each of them property:

      MyClass::BlaBla(){
          ads::CDockWidget* dockWidget = new ads::CDockWidget("2D Window");
          dockWidget->setWidget(qvtkOpenGLStereoWidget);
          dockWidget->setProperty("IsVisualization", true);
          dockManager->addDockWidget(ads::RightDockWidgetArea, dockWidget);
      }
      

      If I write QVariant variant = dockWidget->property("IsVisualization"); then the variant contains correct data everything if ok at this step.
      But if I do the same in the MainWindow inside onFocusChanged method I get invalid QVariant:

      void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
          if (old != nullptr){
              QVariant variantOLD = old->property("IsVisualization");
          }
          if (now != nullptr){
              QVariant variantNOW = now->property("IsVisualization");
          }
      }
      

      What is wrong?

      P.S. dockManager and dockWidget are from advanced_docking_system library

      JonBJ 1 Reply Last reply
      0
      • Please_Help_me_DP Please_Help_me_D

        @SGaist I'm trying to use bool QObject::setProperty(const char *name, const QVariant &value)
        In my MainWindow I call MyClass where I create some objects and set for each of them property:

        MyClass::BlaBla(){
            ads::CDockWidget* dockWidget = new ads::CDockWidget("2D Window");
            dockWidget->setWidget(qvtkOpenGLStereoWidget);
            dockWidget->setProperty("IsVisualization", true);
            dockManager->addDockWidget(ads::RightDockWidgetArea, dockWidget);
        }
        

        If I write QVariant variant = dockWidget->property("IsVisualization"); then the variant contains correct data everything if ok at this step.
        But if I do the same in the MainWindow inside onFocusChanged method I get invalid QVariant:

        void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
            if (old != nullptr){
                QVariant variantOLD = old->property("IsVisualization");
            }
            if (now != nullptr){
                QVariant variantNOW = now->property("IsVisualization");
            }
        }
        

        What is wrong?

        P.S. dockManager and dockWidget are from advanced_docking_system library

        JonBJ Offline
        JonBJ Offline
        JonB
        wrote on last edited by JonB
        #5

        @Please_Help_me_D
        Since being inside onFocusChanged() makes no difference to whether you can read a property or not, I can only conclude that neither old nor now are the dockWidget on which you previously set the property, or you have reset it since then.

        Did you even try object_cast<>ing old/now to verify they are ads::CDockWidget*?

        Please_Help_me_DP 1 Reply Last reply
        2
        • JonBJ JonB

          @Please_Help_me_D
          Since being inside onFocusChanged() makes no difference to whether you can read a property or not, I can only conclude that neither old nor now are the dockWidget on which you previously set the property, or you have reset it since then.

          Did you even try object_cast<>ing old/now to verify they are ads::CDockWidget*?

          Please_Help_me_DP Offline
          Please_Help_me_DP Offline
          Please_Help_me_D
          wrote on last edited by
          #6

          @JonB after you wrote I tried it... Yes you are right, they are not a ads::CDockWidget*
          I guess I should be able to get ads::CDockWidget* from old/now via old->children?

          JonBJ 1 Reply Last reply
          0
          • Please_Help_me_DP Please_Help_me_D

            @JonB after you wrote I tried it... Yes you are right, they are not a ads::CDockWidget*
            I guess I should be able to get ads::CDockWidget* from old/now via old->children?

            JonBJ Offline
            JonBJ Offline
            JonB
            wrote on last edited by JonB
            #7

            @Please_Help_me_D
            I was doing this just today. The focus can be hitting some sub widget on a container. In my case widgets on a QMdiSubWindow. To find that I go up via parentWidget() till I find one or hit the topmost. If you are same thing you will want to go up parents from old/now, not chidren?

            Please_Help_me_DP 1 Reply Last reply
            1
            • JonBJ JonB

              @Please_Help_me_D
              I was doing this just today. The focus can be hitting some sub widget on a container. In my case widgets on a QMdiSubWindow. To find that I go up via parentWidget() till I find one or hit the topmost. If you are same thing you will want to go up parents from old/now, not chidren?

              Please_Help_me_DP Offline
              Please_Help_me_DP Offline
              Please_Help_me_D
              wrote on last edited by
              #8

              @JonB nice to hear that
              As I understood I should go up from old/now until I meet ads::CDockWidget* dockWidget != nullptr condition, correct? Like:

              {
              ads::CDockWidget* dockWidget = qobject_cast<ads::CDockWidget*>(old->parent());
              if (CDockWidget != nullptr){}
              }
              

              but in some while or for loop...

              JonBJ 1 Reply Last reply
              0
              • Please_Help_me_DP Please_Help_me_D

                @JonB nice to hear that
                As I understood I should go up from old/now until I meet ads::CDockWidget* dockWidget != nullptr condition, correct? Like:

                {
                ads::CDockWidget* dockWidget = qobject_cast<ads::CDockWidget*>(old->parent());
                if (CDockWidget != nullptr){}
                }
                

                but in some while or for loop...

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by JonB
                #9

                @Please_Help_me_D

                ads::CDockWidget* dockWidget = nullptr;
                while (old != nullptr && (dockWidget = qobject_cast<ads::CDockWidget*>(old)) == nullptr)
                    old = old->parentWidget();
                qDebug() << dockWidget;
                
                Please_Help_me_DP 1 Reply Last reply
                1
                • JonBJ JonB

                  @Please_Help_me_D

                  ads::CDockWidget* dockWidget = nullptr;
                  while (old != nullptr && (dockWidget = qobject_cast<ads::CDockWidget*>(old)) == nullptr)
                      old = old->parentWidget();
                  qDebug() << dockWidget;
                  
                  Please_Help_me_DP Offline
                  Please_Help_me_DP Offline
                  Please_Help_me_D
                  wrote on last edited by
                  #10

                  @JonB thank you
                  But the loop ended and dockWidget is always nullptr. It takes about 7 cycles and there is no ads::CDockWidget*

                  JonBJ 1 Reply Last reply
                  0
                  • Please_Help_me_DP Please_Help_me_D

                    @JonB thank you
                    But the loop ended and dockWidget is always nullptr. It takes about 7 cycles and there is no ads::CDockWidget*

                    JonBJ Offline
                    JonBJ Offline
                    JonB
                    wrote on last edited by
                    #11

                    @Please_Help_me_D
                    So in that case the old or now (you have written this loop on both, haven't you?!) in the focus change is not a descendent of your ads::CDockWidget* dockWidget. I never said it was, you did! Or you check children if whatever it is works that way.

                    Please_Help_me_DP 2 Replies Last reply
                    0
                    • JonBJ JonB

                      @Please_Help_me_D
                      So in that case the old or now (you have written this loop on both, haven't you?!) in the focus change is not a descendent of your ads::CDockWidget* dockWidget. I never said it was, you did! Or you check children if whatever it is works that way.

                      Please_Help_me_DP Offline
                      Please_Help_me_DP Offline
                      Please_Help_me_D
                      wrote on last edited by
                      #12

                      @JonB yes I have written both old and now
                      Yes I'm trying to find this widget via old->children();. I need few minuts

                      1 Reply Last reply
                      0
                      • JonBJ JonB

                        @Please_Help_me_D
                        So in that case the old or now (you have written this loop on both, haven't you?!) in the focus change is not a descendent of your ads::CDockWidget* dockWidget. I never said it was, you did! Or you check children if whatever it is works that way.

                        Please_Help_me_DP Offline
                        Please_Help_me_DP Offline
                        Please_Help_me_D
                        wrote on last edited by
                        #13

                        @JonB this code can't find ads::CDockWidget* neither:

                        void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
                            if (old != nullptr){
                                ads::CDockWidget* dockWidget = nullptr;
                                QObjectList objList = old->children();
                                int i = 0;
                                while (i < objList.count() && dockWidget == nullptr){
                                    dockWidget = qobject_cast<ads::CDockWidget*>(objList.at(i));
                                    i++;
                                }
                            }
                        
                            if (now != nullptr){
                                ads::CDockWidget* dockWidget = nullptr;
                                QObjectList objList = now->children();
                                int i = 0;
                                while (i < objList.count() && dockWidget == nullptr){
                                    dockWidget = qobject_cast<ads::CDockWidget*>(objList.at(i));
                                    i++;
                                }
                            }
                        }
                        
                        JonBJ 1 Reply Last reply
                        0
                        • Please_Help_me_DP Please_Help_me_D

                          @JonB this code can't find ads::CDockWidget* neither:

                          void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
                              if (old != nullptr){
                                  ads::CDockWidget* dockWidget = nullptr;
                                  QObjectList objList = old->children();
                                  int i = 0;
                                  while (i < objList.count() && dockWidget == nullptr){
                                      dockWidget = qobject_cast<ads::CDockWidget*>(objList.at(i));
                                      i++;
                                  }
                              }
                          
                              if (now != nullptr){
                                  ads::CDockWidget* dockWidget = nullptr;
                                  QObjectList objList = now->children();
                                  int i = 0;
                                  while (i < objList.count() && dockWidget == nullptr){
                                      dockWidget = qobject_cast<ads::CDockWidget*>(objList.at(i));
                                      i++;
                                  }
                              }
                          }
                          
                          JonBJ Offline
                          JonBJ Offline
                          JonB
                          wrote on last edited by JonB
                          #14

                          @Please_Help_me_D
                          So read up on what a ads::CDockWidget is/how it works. Your assumption in that QWidget::focusChanged(old, now) must lead to widgets either ancestors or descendants of this dock widget. I have no idea whether that is the case. Also your code may need to recurse down through children, no? At least start by finding out what old & now actually are in your focus change.

                          Please_Help_me_DP 1 Reply Last reply
                          0
                          • JonBJ JonB

                            @Please_Help_me_D
                            So read up on what a ads::CDockWidget is/how it works. Your assumption in that QWidget::focusChanged(old, now) must lead to widgets either ancestors or descendants of this dock widget. I have no idea whether that is the case. Also your code may need to recurse down through children, no? At least start by finding out what old & now actually are in your focus change.

                            Please_Help_me_DP Offline
                            Please_Help_me_DP Offline
                            Please_Help_me_D
                            wrote on last edited by
                            #15

                            @JonB yes possibly I should have done the recursion down to the other children but it alredy becomes too complicated solution for such kind of a task.
                            Now I'm trying to set property not on CDockWidget but to some parent. I'm trying...

                            1 Reply Last reply
                            0
                            • mrjjM Offline
                              mrjjM Offline
                              mrjj
                              Lifetime Qt Champion
                              wrote on last edited by
                              #16

                              Hi
                              It wont be the DockWidget that has the focus. it will be its widget/children.

                              I would call dumpObjectTree()
                              on old and now to see how they are made up.

                              Please_Help_me_DP 1 Reply Last reply
                              1
                              • mrjjM mrjj

                                Hi
                                It wont be the DockWidget that has the focus. it will be its widget/children.

                                I would call dumpObjectTree()
                                on old and now to see how they are made up.

                                Please_Help_me_DP Offline
                                Please_Help_me_DP Offline
                                Please_Help_me_D
                                wrote on last edited by Please_Help_me_D
                                #17

                                @mrjj thank you for advice. Here is the output:

                                setFocus(Qt::OtherFocusReason);
                                setFocus(Qt::OtherFocusReason);
                                ads::CDockWidget::2D Window 
                                    QBoxLayout:: 
                                    QAction:: 
                                    QScrollArea::dockWidgetScrollArea 
                                        QWidget::qt_scrollarea_viewport 
                                            QVTKOpenGLStereoWidget:: 
                                                QVBoxLayout:: 
                                                QWindowContainer:: 
                                        QWidget::qt_scrollarea_hcontainer 
                                            QScrollBar:: 
                                            QBoxLayout:: 
                                        QWidget::qt_scrollarea_vcontainer 
                                            QScrollBar:: 
                                            QBoxLayout:: 
                                setFocus(Qt::OtherFocusReason);
                                setFocus(Qt::OtherFocusReason);
                                setFocus(Qt::OtherFocusReason);
                                

                                So the focus should be on one of those?
                                By the way this tree is from ads::CDockWidget
                                Just a moment and I find tree for old
                                /
                                and here is tree for now object:

                                ads::CDockWidgetTab:: 
                                    QBoxLayout:: 
                                    ads::CElidingLabel::dockWidgetTabLabel 
                                    QPushButton::tabCloseButton 
                                
                                mrjjM 1 Reply Last reply
                                0
                                • Please_Help_me_DP Please_Help_me_D

                                  @mrjj thank you for advice. Here is the output:

                                  setFocus(Qt::OtherFocusReason);
                                  setFocus(Qt::OtherFocusReason);
                                  ads::CDockWidget::2D Window 
                                      QBoxLayout:: 
                                      QAction:: 
                                      QScrollArea::dockWidgetScrollArea 
                                          QWidget::qt_scrollarea_viewport 
                                              QVTKOpenGLStereoWidget:: 
                                                  QVBoxLayout:: 
                                                  QWindowContainer:: 
                                          QWidget::qt_scrollarea_hcontainer 
                                              QScrollBar:: 
                                              QBoxLayout:: 
                                          QWidget::qt_scrollarea_vcontainer 
                                              QScrollBar:: 
                                              QBoxLayout:: 
                                  setFocus(Qt::OtherFocusReason);
                                  setFocus(Qt::OtherFocusReason);
                                  setFocus(Qt::OtherFocusReason);
                                  

                                  So the focus should be on one of those?
                                  By the way this tree is from ads::CDockWidget
                                  Just a moment and I find tree for old
                                  /
                                  and here is tree for now object:

                                  ads::CDockWidgetTab:: 
                                      QBoxLayout:: 
                                      ads::CElidingLabel::dockWidgetTabLabel 
                                      QPushButton::tabCloseButton 
                                  
                                  mrjjM Offline
                                  mrjjM Offline
                                  mrjj
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #18

                                  hi
                                  yes it should but we don't have to guess.
                                  you can do
                                  QWidget * fw = qApp->focusWidget();
                                  and check out in the debugger (or qDebug its object name) to see what it is.

                                  It should be possible to get hold of the Dock again to get your data back.

                                  Please_Help_me_DP 2 Replies Last reply
                                  1
                                  • mrjjM mrjj

                                    hi
                                    yes it should but we don't have to guess.
                                    you can do
                                    QWidget * fw = qApp->focusWidget();
                                    and check out in the debugger (or qDebug its object name) to see what it is.

                                    It should be possible to get hold of the Dock again to get your data back.

                                    Please_Help_me_DP Offline
                                    Please_Help_me_DP Offline
                                    Please_Help_me_D
                                    wrote on last edited by
                                    #19

                                    @mrjj QWidget * fw and now widget is the same. See the picture please
                                    1.png

                                    1 Reply Last reply
                                    0
                                    • mrjjM mrjj

                                      hi
                                      yes it should but we don't have to guess.
                                      you can do
                                      QWidget * fw = qApp->focusWidget();
                                      and check out in the debugger (or qDebug its object name) to see what it is.

                                      It should be possible to get hold of the Dock again to get your data back.

                                      Please_Help_me_DP Offline
                                      Please_Help_me_DP Offline
                                      Please_Help_me_D
                                      wrote on last edited by Please_Help_me_D
                                      #20

                                      @mrjj now I'm trying to set property to the tabWidgets to wich CDockWidget belongs to:

                                      QVTKOpenGLStereoWidget* MainWindowObjectCreator::createVTK2DWindow(){
                                          QVTKOpenGLStereoWidget* qvtkOpenGLStereoWidget = new QVTKOpenGLStereoWidget;
                                          ads::CDockWidget* dockWidget = new ads::CDockWidget("2D Window");
                                          dockWidget->setWidget(qvtkOpenGLStereoWidget);
                                          dockManager->addDockWidget(ads::RightDockWidgetArea, dockWidget);
                                          dockWidget->tabWidget()->setProperty("IsVisualization", 4443);
                                          //dockWidget->dumpObjectTree();
                                          return qvtkOpenGLStereoWidget;
                                      }
                                      

                                      but each time I manually change the focus the MainWindow::onFocusChanged(QWidget* old, QWidget* now) works twice:
                                      first time now is the old window
                                      second time is the new window
                                      and when the second time this method works then I get the correct value of property:

                                      void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
                                          QWidget * fw = qApp->focusWidget();
                                          fw->dumpObjectTree();
                                          if (now != nullptr){
                                              now->dumpObjectTree();
                                              QVariant varia = now->property("IsVisualization"); 
                                          }
                                      }
                                      

                                      By the way this works only if the focused window is tabbed. Otherwise the focused widget is not a tabWidget(). So idea to set property to the tabWidget() doesn't seem to work

                                      mrjjM 1 Reply Last reply
                                      0
                                      • Please_Help_me_DP Please_Help_me_D

                                        @mrjj now I'm trying to set property to the tabWidgets to wich CDockWidget belongs to:

                                        QVTKOpenGLStereoWidget* MainWindowObjectCreator::createVTK2DWindow(){
                                            QVTKOpenGLStereoWidget* qvtkOpenGLStereoWidget = new QVTKOpenGLStereoWidget;
                                            ads::CDockWidget* dockWidget = new ads::CDockWidget("2D Window");
                                            dockWidget->setWidget(qvtkOpenGLStereoWidget);
                                            dockManager->addDockWidget(ads::RightDockWidgetArea, dockWidget);
                                            dockWidget->tabWidget()->setProperty("IsVisualization", 4443);
                                            //dockWidget->dumpObjectTree();
                                            return qvtkOpenGLStereoWidget;
                                        }
                                        

                                        but each time I manually change the focus the MainWindow::onFocusChanged(QWidget* old, QWidget* now) works twice:
                                        first time now is the old window
                                        second time is the new window
                                        and when the second time this method works then I get the correct value of property:

                                        void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
                                            QWidget * fw = qApp->focusWidget();
                                            fw->dumpObjectTree();
                                            if (now != nullptr){
                                                now->dumpObjectTree();
                                                QVariant varia = now->property("IsVisualization"); 
                                            }
                                        }
                                        

                                        By the way this works only if the focused window is tabbed. Otherwise the focused widget is not a tabWidget(). So idea to set property to the tabWidget() doesn't seem to work

                                        mrjjM Offline
                                        mrjjM Offline
                                        mrjj
                                        Lifetime Qt Champion
                                        wrote on last edited by mrjj
                                        #21

                                        @Please_Help_me_D

                                        Ah silly me. of cause now will be the same as qApp->focusWidget(); :)
                                        and it does seem to be the actual DockWidget ! which i didn't expect.

                                        Is it possible you have 2 connects to the onFocusChanged signal ?
                                        Not really sure why it should run twice. I don't recall it normally does that.

                                        Its normally not an issue to loop up the chain to find the top parent.
                                        So not sure why it dont seem to work for you here.

                                        Please_Help_me_DP 1 Reply Last reply
                                        1
                                        • mrjjM mrjj

                                          @Please_Help_me_D

                                          Ah silly me. of cause now will be the same as qApp->focusWidget(); :)
                                          and it does seem to be the actual DockWidget ! which i didn't expect.

                                          Is it possible you have 2 connects to the onFocusChanged signal ?
                                          Not really sure why it should run twice. I don't recall it normally does that.

                                          Its normally not an issue to loop up the chain to find the top parent.
                                          So not sure why it dont seem to work for you here.

                                          Please_Help_me_DP Offline
                                          Please_Help_me_DP Offline
                                          Please_Help_me_D
                                          wrote on last edited by
                                          #22

                                          @mrjj yes, now I also find this looking for parent not working for me strange :)
                                          Just a moment I guess that I'm missing something important...

                                          mrjjM 1 Reply Last reply
                                          0

                                          • Login

                                          • Login or register to search.
                                          • First post
                                            Last post
                                          0
                                          • Categories
                                          • Recent
                                          • Tags
                                          • Popular
                                          • Users
                                          • Groups
                                          • Search
                                          • Get Qt Extensions
                                          • Unsolved