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Add a QCheckBox as a header to a QTableWidget

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  • Chris KawaC Chris Kawa

    Sigh... right, don't you just love when internet examples are buggy? :P

    Here's a fixed version:

    class MyHeader : public QHeaderView
    {
    public:
        using QHeaderView::QHeaderView;
    
    protected:
    
        void paintSection(QPainter* painter, const QRect &rect, int logicalIndex) const override
        {
            painter->save();
            QHeaderView::paintSection(painter, rect, logicalIndex);
            painter->restore();
    
            if (model() && logicalIndex >= 0)
            {
                QStyleOptionButton option;
                option.init(this);
    
                QRect checkbox_rect = style()->subElementRect(QStyle::SubElement::SE_CheckBoxIndicator, &option, this);
                checkbox_rect.moveCenter(rect.center());
    
                bool checked = model()->headerData(logicalIndex, orientation(), Qt::CheckStateRole).toBool();
    
                option.rect = checkbox_rect;
                option.state = checked ? QStyle::State_On : QStyle::State_Off;
    
                style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter);
            }
        }
    
        void mouseReleaseEvent(QMouseEvent* event) override
        {
            QHeaderView::mouseReleaseEvent(event);
            if(model())
            {
                int section = logicalIndexAt(event->pos());
                if (section >= 0)
                {
                    bool checked = model()->headerData(section, orientation(), Qt::CheckStateRole).toBool();
                    model()->setHeaderData(section, orientation(), !checked, Qt::CheckStateRole);
                    viewport()->update();
                }
            }
        }
    };
    

    Just a note - for simplicity this version toggles the checkbox whenever you click anywhere in the header section. You should probably shrink this area to only the actual checkbox. You have all the info in the example - just get the checkbox rectangle and see if the click was inside it.

    H Offline
    H Offline
    hbatalha
    wrote on last edited by hbatalha
    #8

    @Chris-Kawa thanks for the code.

    I believe that instead of this line

    option.init(this);

    you meant
    option.initFrom(this); becasue the compiler complains about the non-existence of init

    A question:
    How can I add MyHeader only to the first colum like in the buggy example, instead of adding to all the columns in the header?

    Edit: To add MyHeader only to the first colum I just edited this line:

    if (model() && logicalIndex >= 0)
    

    to

    if (model() && logicalIndex == 0)
    
    1 Reply Last reply
    1
    • Chris KawaC Chris Kawa

      Sigh... right, don't you just love when internet examples are buggy? :P

      Here's a fixed version:

      class MyHeader : public QHeaderView
      {
      public:
          using QHeaderView::QHeaderView;
      
      protected:
      
          void paintSection(QPainter* painter, const QRect &rect, int logicalIndex) const override
          {
              painter->save();
              QHeaderView::paintSection(painter, rect, logicalIndex);
              painter->restore();
      
              if (model() && logicalIndex >= 0)
              {
                  QStyleOptionButton option;
                  option.init(this);
      
                  QRect checkbox_rect = style()->subElementRect(QStyle::SubElement::SE_CheckBoxIndicator, &option, this);
                  checkbox_rect.moveCenter(rect.center());
      
                  bool checked = model()->headerData(logicalIndex, orientation(), Qt::CheckStateRole).toBool();
      
                  option.rect = checkbox_rect;
                  option.state = checked ? QStyle::State_On : QStyle::State_Off;
      
                  style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter);
              }
          }
      
          void mouseReleaseEvent(QMouseEvent* event) override
          {
              QHeaderView::mouseReleaseEvent(event);
              if(model())
              {
                  int section = logicalIndexAt(event->pos());
                  if (section >= 0)
                  {
                      bool checked = model()->headerData(section, orientation(), Qt::CheckStateRole).toBool();
                      model()->setHeaderData(section, orientation(), !checked, Qt::CheckStateRole);
                      viewport()->update();
                  }
              }
          }
      };
      

      Just a note - for simplicity this version toggles the checkbox whenever you click anywhere in the header section. You should probably shrink this area to only the actual checkbox. You have all the info in the example - just get the checkbox rectangle and see if the click was inside it.

      H Offline
      H Offline
      hbatalha
      wrote on last edited by
      #9

      @Chris-Kawa How would I implement a clicked() signal mechanism?

      mrjjM 1 Reply Last reply
      0
      • H hbatalha

        @Chris-Kawa How would I implement a clicked() signal mechanism?

        mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by mrjj
        #10

        @hbatalha

        Hi
        you would define a signal in .h ( in the class)

        ..
        signals:
        void Clicked();

        then use it with the keyword emit
        in void mouseReleaseEvent(QMouseEvent* event)
        in the spot where you check/uncheck ( maybe after viewport()->update(); )
        like

        emit clicked();
        

        Do not i didn't put a parameter here to the clicked signal but in real world you might want to consider adding an int/id to say which section was clicked.

        1 Reply Last reply
        4
        • Chris KawaC Offline
          Chris KawaC Offline
          Chris Kawa
          Lifetime Qt Champion
          wrote on last edited by
          #11

          Just to add to what @mrjj said - a click is when you press and release mouse button on the same widget.

          Having said that you shouldn't just always emit it in release event. You should record in press event which section was pressed, then in release check if it's the same one and only then emit a clicked signal.

          If you release on different section than the one you press on nothing should happen. This is for the purpose of user realizing mid-click that they pressed on the wrong area. They can then move the mouse away and release and this is basically cancelling the click.

          H 1 Reply Last reply
          3
          • Chris KawaC Chris Kawa

            Just to add to what @mrjj said - a click is when you press and release mouse button on the same widget.

            Having said that you shouldn't just always emit it in release event. You should record in press event which section was pressed, then in release check if it's the same one and only then emit a clicked signal.

            If you release on different section than the one you press on nothing should happen. This is for the purpose of user realizing mid-click that they pressed on the wrong area. They can then move the mouse away and release and this is basically cancelling the click.

            H Offline
            H Offline
            hbatalha
            wrote on last edited by hbatalha
            #12

            @Chris-Kawa @mrjj Done.

            Is there a way to control the checkbox programatically, sending the signal and get the checkbox checked. I need the checkbox default state to be checked and I need to uncheck it when I uncheck any checkbox in the rows in the qtablewidget. Like in the OP image.

            mrjjM 1 Reply Last reply
            1
            • H hbatalha

              @Chris-Kawa @mrjj Done.

              Is there a way to control the checkbox programatically, sending the signal and get the checkbox checked. I need the checkbox default state to be checked and I need to uncheck it when I uncheck any checkbox in the rows in the qtablewidget. Like in the OP image.

              mrjjM Offline
              mrjjM Offline
              mrjj
              Lifetime Qt Champion
              wrote on last edited by
              #13

              @hbatalha
              hi
              it uses the model so you can just set it in model

               model->setHeaderData(section, orientation(), true/false, Qt::CheckStateRole);
              
              H 1 Reply Last reply
              1
              • mrjjM mrjj

                @hbatalha
                hi
                it uses the model so you can just set it in model

                 model->setHeaderData(section, orientation(), true/false, Qt::CheckStateRole);
                
                H Offline
                H Offline
                hbatalha
                wrote on last edited by
                #14

                @mrjj said in Add a QCheckBox as a header to a QTableWidget:

                model->setHeaderData(section, orientation(), true/false, Qt::CheckStateRole);

                what would be the value of section?

                mrjjM 1 Reply Last reply
                0
                • H hbatalha

                  @mrjj said in Add a QCheckBox as a header to a QTableWidget:

                  model->setHeaderData(section, orientation(), true/false, Qt::CheckStateRole);

                  what would be the value of section?

                  mrjjM Offline
                  mrjjM Offline
                  mrjj
                  Lifetime Qt Champion
                  wrote on last edited by mrjj
                  #15

                  @hbatalha
                  just 0,1,2,3,4 for the sections.
                  unless you allow drag to reorder then you have to use
                  https://doc.qt.io/qt-5/qheaderview.html#visualIndex
                  to map to the right index/ID

                  H L 2 Replies Last reply
                  2
                  • mrjjM mrjj

                    @hbatalha
                    just 0,1,2,3,4 for the sections.
                    unless you allow drag to reorder then you have to use
                    https://doc.qt.io/qt-5/qheaderview.html#visualIndex
                    to map to the right index/ID

                    H Offline
                    H Offline
                    hbatalha
                    wrote on last edited by
                    #16

                    @mrjj I gave it 0.

                    Everything is working perfect.

                    Thank you all!!!

                    1 Reply Last reply
                    1
                    • mrjjM mrjj

                      @hbatalha
                      just 0,1,2,3,4 for the sections.
                      unless you allow drag to reorder then you have to use
                      https://doc.qt.io/qt-5/qheaderview.html#visualIndex
                      to map to the right index/ID

                      L Offline
                      L Offline
                      lisukovigor492
                      wrote on last edited by lisukovigor492
                      #17

                      @mrjj just 0,1,2,3,4 for the sections.
                      unless you allow drag to reorder then you have to use
                      https://doc.qt.io/qt-5/qheaderview.html#visualIndex https://www.worktime.com/employee-time-tracking-software
                      to map to the right index/ID

                      Hello,
                      the question is too simple, but I'm a beginner, please tell me what parameters of the indexer should be?

                      Thank you

                      mrjjM 1 Reply Last reply
                      0
                      • L lisukovigor492

                        @mrjj just 0,1,2,3,4 for the sections.
                        unless you allow drag to reorder then you have to use
                        https://doc.qt.io/qt-5/qheaderview.html#visualIndex https://www.worktime.com/employee-time-tracking-software
                        to map to the right index/ID

                        Hello,
                        the question is too simple, but I'm a beginner, please tell me what parameters of the indexer should be?

                        Thank you

                        mrjjM Offline
                        mrjjM Offline
                        mrjj
                        Lifetime Qt Champion
                        wrote on last edited by mrjj
                        #18

                        @lisukovigor492
                        Hi
                        you mean for the
                        int QHeaderView::visualIndex(int logicalIndex) ?

                        well its for when its reordered. then say index 5 is in front and then comes 2 and so on.
                        The issues is they are no longer in order.

                        so you use

                        int realIndex = HeaderView->visualIndex(0)
                        and IF the header is reorderd it will then tell you what index is a section 0.
                        like 7. or what ever what dragged there.

                        there is also
                        int QHeaderView::logicalIndex(int visualIndex)

                        I might recall it reverse. :) but they allow to map between the sections you see on screen and their real Id/indexs.

                        But this is only important if you allow user to move the sections around.

                        To get to know them, you could enable it and then
                        drag some around and the see what therse functions returns for the sections.

                        its all just integers values so nothing fancy at all.

                        1 Reply Last reply
                        0
                        • Chris KawaC Chris Kawa

                          Sigh... right, don't you just love when internet examples are buggy? :P

                          Here's a fixed version:

                          class MyHeader : public QHeaderView
                          {
                          public:
                              using QHeaderView::QHeaderView;
                          
                          protected:
                          
                              void paintSection(QPainter* painter, const QRect &rect, int logicalIndex) const override
                              {
                                  painter->save();
                                  QHeaderView::paintSection(painter, rect, logicalIndex);
                                  painter->restore();
                          
                                  if (model() && logicalIndex >= 0)
                                  {
                                      QStyleOptionButton option;
                                      option.init(this);
                          
                                      QRect checkbox_rect = style()->subElementRect(QStyle::SubElement::SE_CheckBoxIndicator, &option, this);
                                      checkbox_rect.moveCenter(rect.center());
                          
                                      bool checked = model()->headerData(logicalIndex, orientation(), Qt::CheckStateRole).toBool();
                          
                                      option.rect = checkbox_rect;
                                      option.state = checked ? QStyle::State_On : QStyle::State_Off;
                          
                                      style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter);
                                  }
                              }
                          
                              void mouseReleaseEvent(QMouseEvent* event) override
                              {
                                  QHeaderView::mouseReleaseEvent(event);
                                  if(model())
                                  {
                                      int section = logicalIndexAt(event->pos());
                                      if (section >= 0)
                                      {
                                          bool checked = model()->headerData(section, orientation(), Qt::CheckStateRole).toBool();
                                          model()->setHeaderData(section, orientation(), !checked, Qt::CheckStateRole);
                                          viewport()->update();
                                      }
                                  }
                              }
                          };
                          

                          Just a note - for simplicity this version toggles the checkbox whenever you click anywhere in the header section. You should probably shrink this area to only the actual checkbox. You have all the info in the example - just get the checkbox rectangle and see if the click was inside it.

                          H Offline
                          H Offline
                          hbatalha
                          wrote on last edited by
                          #19

                          @Chris-Kawa is there a way to change the checkbox border and mark color so it doesn't look grayed outScreenshot_1.png

                          I have tried

                          QPalette p(Qt::black);
                          style()->polish(p);
                          
                          painter->setPen(Qt::black);
                          painter->setBrush(Qt::back);
                          
                          option.palette = QPalette(Qt::black);
                          

                          But none of the above worked.
                          Is there a way to change its color?

                          Chris KawaC 1 Reply Last reply
                          0
                          • H hbatalha

                            @Chris-Kawa is there a way to change the checkbox border and mark color so it doesn't look grayed outScreenshot_1.png

                            I have tried

                            QPalette p(Qt::black);
                            style()->polish(p);
                            
                            painter->setPen(Qt::black);
                            painter->setBrush(Qt::back);
                            
                            option.palette = QPalette(Qt::black);
                            

                            But none of the above worked.
                            Is there a way to change its color?

                            Chris KawaC Offline
                            Chris KawaC Offline
                            Chris Kawa
                            Lifetime Qt Champion
                            wrote on last edited by
                            #20

                            @hbatalha It's an image so changing pen, brush or palette doesn't affect it. It might appear disabled if you give it the wrong state flags when painting, so check that the state member is set correctly in the style option.
                            The checkbox also appears crooked in your screenshot, which suggests the rect member is set incorrectly, so again make sure you set all the members of your style options object correctly before painting with it.

                            H 1 Reply Last reply
                            1
                            • Chris KawaC Chris Kawa

                              @hbatalha It's an image so changing pen, brush or palette doesn't affect it. It might appear disabled if you give it the wrong state flags when painting, so check that the state member is set correctly in the style option.
                              The checkbox also appears crooked in your screenshot, which suggests the rect member is set incorrectly, so again make sure you set all the members of your style options object correctly before painting with it.

                              H Offline
                              H Offline
                              hbatalha
                              wrote on last edited by hbatalha
                              #21

                              @Chris-Kawa said in Add a QCheckBox as a header to a QTableWidget:

                              so again make sure you set all the members of your style options object correctly before painting with it.

                              The code is like the one you provided in your answer above:

                              class CheckBox : public QHeaderView
                              {
                                  Q_OBJECT
                              
                              public:
                                  using QHeaderView::QHeaderView;
                              
                              signals:
                                  void clicked(bool);
                              
                              protected:
                              
                                  void paintSection(QPainter* painter, const QRect &rect, int logicalIndex) const override
                                  {
                                      painter->save();
                                      QHeaderView::paintSection(painter, rect, logicalIndex);
                                      painter->restore();
                              
                                      if (model() && logicalIndex == 0)
                                      {
                                          QStyleOptionButton option;
                                          option.initFrom(this);
                              
                                          QRect checkbox_rect = style()->subElementRect(QStyle::SubElement::SE_CheckBoxIndicator, &option, this);
                                          checkbox_rect.moveLeft(rect.left());
                              
                                          bool checked = model()->headerData(logicalIndex, orientation(), Qt::CheckStateRole).toBool();
                              
                                          option.rect = checkbox_rect;
                                          option.state = checked ? QStyle::State_On : QStyle::State_Off;
                              
                                          style()->drawPrimitive(QStyle::PE_IndicatorCheckBox, &option, painter);
                                      }
                                  }
                              
                              public:
                              
                                  void mouseReleaseEvent(QMouseEvent* event) override
                                  {
                                      QHeaderView::mouseReleaseEvent(event);
                                      if(model())
                                      {
                                          int section = logicalIndexAt(event->pos());
                                          if (section >= 0)
                                          {
                                              bool checked = model()->headerData(section, orientation(), Qt::CheckStateRole).toBool();
                                              model()->setHeaderData(section, orientation(), !checked, Qt::CheckStateRole);
                                              viewport()->update();
                                              emit clicked( ! checked);
                                          }
                                      }
                                  }
                              };
                              

                              Edit: The problem is only on windows for the looks of it as I just tested it on linux mint 20.1 and it looks totally fine

                              1 Reply Last reply
                              0
                              • N Offline
                                N Offline
                                nonskill
                                wrote on last edited by
                                #22

                                No one mentioned how to add Checkbox in QTableWidget header with PartiallyChecked support, anyone knowns how to make it? There only option for Checkbox is just QStyle::State_On and QStyle::State_Off, which is far from functional. The most important option QStyle::State_Partial is not found.

                                JonBJ 1 Reply Last reply
                                0
                                • N nonskill

                                  No one mentioned how to add Checkbox in QTableWidget header with PartiallyChecked support, anyone knowns how to make it? There only option for Checkbox is just QStyle::State_On and QStyle::State_Off, which is far from functional. The most important option QStyle::State_Partial is not found.

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

                                  @nonskill
                                  Did you try QStyle::State_NoChange ("Used to indicate a tri-state checkbox.") from flags QStyle::State?

                                  1 Reply Last reply
                                  1

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