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tableWidget question

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  • J jenya7

    @JonB
    Didn't understand much from the documentation how I apply all this specifically to a tableWidget.

    JonBJ Offline
    JonBJ Offline
    JonB
    wrote on last edited by
    #4

    @jenya7
    A QTableWidget is derived from a QAbstractItemView so these methods are available (https://doc.qt.io/qt-5/qtablewidget-members.html). There is nothing special about it being a QTableWidget.

    J 1 Reply Last reply
    1
    • JonBJ JonB

      @jenya7
      A QTableWidget is derived from a QAbstractItemView so these methods are available (https://doc.qt.io/qt-5/qtablewidget-members.html). There is nothing special about it being a QTableWidget.

      J Offline
      J Offline
      jenya7
      wrote on last edited by
      #5

      @JonB said in tableWidget question:

      @jenya7
      A QTableWidget is derived from a QAbstractItemView so these methods are available (https://doc.qt.io/qt-5/qtablewidget-members.html). There is nothing special about it being a QTableWidget.

      It's all foreign language to me. I am completely new in Qt.

      1 Reply Last reply
      0
      • SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #6

        Hi,

        That is nothing specific to Qt. It's C++ inheritance.

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        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

        1 Reply Last reply
        2
        • mrjjM Offline
          mrjjM Offline
          mrjj
          Lifetime Qt Champion
          wrote on last edited by mrjj
          #7

          Hi
          A delegate is a helper class that can draw the cell and/or also allows editing.
          Here is an example of a special one. Like a rating bar with stars
          https://doc.qt.io/qt-5/qtwidgets-itemviews-stardelegate-example.html

          You can see how to make one for a combobox here
          https://wiki.qt.io/Combo_Boxes_in_Item_Views
          This way can be used with any Widget you want. In the CreateEditor you just create another one. rest of code is much the same.

          For the checkbox, you can actually set on the Items you insert that they can be checked ( like a checkbox)

          QTableWidgetItem *item2 = new QTableWidgetItem("Item2");
          item2->setCheckState(Qt::Checked); // or unchecked
          tableWidget->setItem(0, 0, item2);
          
          J 1 Reply Last reply
          2
          • mrjjM mrjj

            Hi
            A delegate is a helper class that can draw the cell and/or also allows editing.
            Here is an example of a special one. Like a rating bar with stars
            https://doc.qt.io/qt-5/qtwidgets-itemviews-stardelegate-example.html

            You can see how to make one for a combobox here
            https://wiki.qt.io/Combo_Boxes_in_Item_Views
            This way can be used with any Widget you want. In the CreateEditor you just create another one. rest of code is much the same.

            For the checkbox, you can actually set on the Items you insert that they can be checked ( like a checkbox)

            QTableWidgetItem *item2 = new QTableWidgetItem("Item2");
            item2->setCheckState(Qt::Checked); // or unchecked
            tableWidget->setItem(0, 0, item2);
            
            J Offline
            J Offline
            jenya7
            wrote on last edited by
            #8
            This post is deleted!
            J 1 Reply Last reply
            0
            • J jenya7

              This post is deleted!

              J Offline
              J Offline
              jenya7
              wrote on last edited by jenya7
              #9

              @jenya7 said in tableWidget question:

              @mrjj said in tableWidget question:

              Hi
              A delegate is a helper class that can draw the cell and/or also allows editing.
              Here is an example of a special one. Like a rating bar with stars
              https://doc.qt.io/qt-5/qtwidgets-itemviews-stardelegate-example.html

              You can see how to make one for a combobox here
              https://wiki.qt.io/Combo_Boxes_in_Item_Views
              This way can be used with any Widget you want. In the CreateEditor you just create another one. rest of code is much the same.

              For the checkbox, you can actually set on the Items you insert that they can be checked ( like a checkbox)

              QTableWidgetItem *item2 = new QTableWidgetItem("Item2");
              item2->setCheckState(Qt::Checked); // or unchecked
              tableWidget->setItem(0, 0, item2);
              

              Thank you. The first argument is a row number. But tableWidget is not populated yet. I start to add rows and on every row I should call tableWidget->setItem(row_num, 0, item2); ?

              JonBJ 1 Reply Last reply
              0
              • J jenya7

                @jenya7 said in tableWidget question:

                @mrjj said in tableWidget question:

                Hi
                A delegate is a helper class that can draw the cell and/or also allows editing.
                Here is an example of a special one. Like a rating bar with stars
                https://doc.qt.io/qt-5/qtwidgets-itemviews-stardelegate-example.html

                You can see how to make one for a combobox here
                https://wiki.qt.io/Combo_Boxes_in_Item_Views
                This way can be used with any Widget you want. In the CreateEditor you just create another one. rest of code is much the same.

                For the checkbox, you can actually set on the Items you insert that they can be checked ( like a checkbox)

                QTableWidgetItem *item2 = new QTableWidgetItem("Item2");
                item2->setCheckState(Qt::Checked); // or unchecked
                tableWidget->setItem(0, 0, item2);
                

                Thank you. The first argument is a row number. But tableWidget is not populated yet. I start to add rows and on every row I should call tableWidget->setItem(row_num, 0, item2); ?

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by
                #10

                @jenya7
                You can only do that once the row, row_num, exists in the table. You will need to have called https://doc.qt.io/qt-5/qtablewidget.html#insertRow to insert the row(s) beforehand.

                1 Reply Last reply
                2
                • mrjjM Offline
                  mrjjM Offline
                  mrjj
                  Lifetime Qt Champion
                  wrote on last edited by
                  #11

                  Hi
                  This might come in handy
                  https://wiki.qt.io/How_to_Use_QTableWidget

                  J 1 Reply Last reply
                  1
                  • mrjjM mrjj

                    Hi
                    This might come in handy
                    https://wiki.qt.io/How_to_Use_QTableWidget

                    J Offline
                    J Offline
                    jenya7
                    wrote on last edited by
                    #12

                    @mrjj said in tableWidget question:

                    Hi
                    This might come in handy
                    https://wiki.qt.io/How_to_Use_QTableWidget

                    Thank you. One more question - after populating the table - how can I check/uncheck a check box in a row or to check a check box state?

                    mrjjM 1 Reply Last reply
                    0
                    • J jenya7

                      @mrjj said in tableWidget question:

                      Hi
                      This might come in handy
                      https://wiki.qt.io/How_to_Use_QTableWidget

                      Thank you. One more question - after populating the table - how can I check/uncheck a check box in a row or to check a check box state?

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

                      @jenya7
                      Hi
                      There is https://doc.qt.io/qt-5/qtablewidget.html#item
                      where you can access the items to check or uncheck it.

                      But often you use some of the signals
                      like
                      https://doc.qt.io/qt-5/qtablewidget.html#itemChanged
                      and there you directly get the item.

                      J 1 Reply Last reply
                      1
                      • mrjjM mrjj

                        @jenya7
                        Hi
                        There is https://doc.qt.io/qt-5/qtablewidget.html#item
                        where you can access the items to check or uncheck it.

                        But often you use some of the signals
                        like
                        https://doc.qt.io/qt-5/qtablewidget.html#itemChanged
                        and there you directly get the item.

                        J Offline
                        J Offline
                        jenya7
                        wrote on last edited by
                        #14

                        @mrjj said in tableWidget question:

                        @jenya7
                        Hi
                        There is https://doc.qt.io/qt-5/qtablewidget.html#item
                        where you can access the items to check or uncheck it.

                        But often you use some of the signals
                        like
                        https://doc.qt.io/qt-5/qtablewidget.html#itemChanged
                        and there you directly get the item.

                        Thank you.

                        1 Reply Last reply
                        0
                        • J Offline
                          J Offline
                          jenya7
                          wrote on last edited by
                          #15

                          I did so

                          void sys::ParamLoadToTable(QTableWidget *table, int rows)
                          {
                          
                              QTableWidgetItem item;
                          
                              table->setRowCount(rows);
                          
                              for (int i = 0; i < rows; i++)
                              {
                                  auto box = new QCheckBox();
                                  box->setCheckState(Qt::Unchecked);
                          
                                  table->setCellWidget(i, 3, box);
                          
                                  item.setText(param_list[i].name);
                                  table->setItem(i, 1, &item);
                              }
                          }
                          

                          I see all rows but column 1 (name) is empty.

                          1 Reply Last reply
                          0
                          • J Offline
                            J Offline
                            jenya7
                            wrote on last edited by
                            #16

                            OK. This way it works

                            for (int i = 0; i < rows; i++)
                                {
                                    auto box = new QCheckBox();
                                    box->setCheckState(Qt::Unchecked);
                            
                                    table->setCellWidget(i, 3, box);
                            
                                     QTableWidgetItem  * item1 = new QTableWidgetItem();
                                     table->setItem(i, 1, item1);
                                   
                                     QTableWidgetItem  * item2 = new QTableWidgetItem();
                                      table->setItem(i, 2, item2);
                            
                                    item1->setText(param_list[i].name);
                                    item2->setText(param_list[i].value);
                                }
                            
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                            0
                            • J Offline
                              J Offline
                              jenya7
                              wrote on last edited by
                              #17

                              How can I check if a check box in the 4-th column is set?

                              mrjjM 1 Reply Last reply
                              0
                              • J jenya7

                                How can I check if a check box in the 4-th column is set?

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

                                @jenya7
                                Hi
                                You can use
                                https://doc.qt.io/qt-5/qtablewidget.html#cellWidget
                                to gain access to the checkbox.

                                J 1 Reply Last reply
                                0
                                • mrjjM mrjj

                                  @jenya7
                                  Hi
                                  You can use
                                  https://doc.qt.io/qt-5/qtablewidget.html#cellWidget
                                  to gain access to the checkbox.

                                  J Offline
                                  J Offline
                                  jenya7
                                  wrote on last edited by
                                  #19

                                  @mrjj said in tableWidget question:

                                  @jenya7
                                  Hi
                                  You can use
                                  https://doc.qt.io/qt-5/qtablewidget.html#cellWidget
                                  to gain access to the checkbox.

                                   QWidget *box = table->cellWidget(i, 3);
                                  

                                  Then what? How do I get the check box state from the object?

                                  mrjjM 1 Reply Last reply
                                  0
                                  • Christian EhrlicherC Offline
                                    Christian EhrlicherC Offline
                                    Christian Ehrlicher
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #20

                                    @jenya7 said in tableWidget question:

                                    How do I get the check box state from the object?

                                    Try to cast it to a QCheckBox (with e.g. dynamic_cast or Qt's specific qobject_cast) and retrieve the information.

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                                    1 Reply Last reply
                                    2
                                    • J jenya7

                                      @mrjj said in tableWidget question:

                                      @jenya7
                                      Hi
                                      You can use
                                      https://doc.qt.io/qt-5/qtablewidget.html#cellWidget
                                      to gain access to the checkbox.

                                       QWidget *box = table->cellWidget(i, 3);
                                      

                                      Then what? How do I get the check box state from the object?

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

                                      @jenya7
                                      Hi
                                      It returns a base Widget pointer so you need to cast it.

                                      QCheckBox * checkbox = qobject_cast<QCheckBox * > (table->cellWidget(i, 3)) ;
                                      if (checkbox) { // must check. can be NULL
                                      if ( checkbox->isChecked() ) ....
                                      }

                                      J 1 Reply Last reply
                                      3
                                      • mrjjM mrjj

                                        @jenya7
                                        Hi
                                        It returns a base Widget pointer so you need to cast it.

                                        QCheckBox * checkbox = qobject_cast<QCheckBox * > (table->cellWidget(i, 3)) ;
                                        if (checkbox) { // must check. can be NULL
                                        if ( checkbox->isChecked() ) ....
                                        }

                                        J Offline
                                        J Offline
                                        jenya7
                                        wrote on last edited by
                                        #22

                                        @mrjj said in tableWidget question:

                                        @jenya7
                                        Hi
                                        It returns a base Widget pointer so you need to cast it.

                                        QCheckBox * checkbox = qobject_cast<QCheckBox * > (table->cellWidget(i, 3)) ;
                                        if (checkbox) { // must check. can be NULL
                                        if ( checkbox->isChecked() ) ....
                                        }

                                        Thank you.

                                        1 Reply Last reply
                                        0
                                        • JonBJ JonB

                                          @jenya7
                                          Yes, you should do so via https://doc.qt.io/qt-5/qabstractitemview.html#setItemDelegateForColumn with a https://doc.qt.io/qt-5/qstyleditemdelegate.html which you write for each of the desired column types.

                                          Although you might be tempted to use https://doc.qt.io/qt-5/qabstractitemview.html#setIndexWidget, you will have @VRonin descending on you like a ton of bricks here if you do so :)

                                          VRoninV Offline
                                          VRoninV Offline
                                          VRonin
                                          wrote on last edited by
                                          #23

                                          @JonB said in tableWidget question:

                                          you might be tempted to use https://doc.qt.io/qt-5/qabstractitemview.html#setIndexWidget, you will have @VRonin descending on you like a ton of bricks here if you do so

                                          And here I am!

                                          Also QCheckBox is the worst excuse to use this method. It's much easier to do without a widget.

                                          To activate a checkbox in a cell you can just call:

                                          QTableWidgetItem  *checkBoxitem = new QTableWidgetItem;
                                          checkBoxitem->setCheckState(Qt::Unchecked); // displays the checkbox as unchecked
                                          checkBoxitem->setFlags(checkBoxitem->flags() | Qt::ItemIsUserCheckable); // allows the user to click on the checkbox
                                          table->setItem(i, 3, checkBoxitem);
                                          

                                          You can then check the item state using item->checkState() or widget->model()->index(row,column).data(Qt::CheckStateRole)

                                          "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

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