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. QListWidget item editing
Forum Updated to NodeBB v4.3 + New Features

QListWidget item editing

Scheduled Pinned Locked Moved Solved General and Desktop
17 Posts 5 Posters 8.1k 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.
  • dheerendraD Offline
    dheerendraD Offline
    dheerendra
    Qt Champions 2022
    wrote on last edited by
    #4

    Did you get a chance to look other set of signals like.

    currentItemChanged(..)
    clicked(..)
    entered(..)
    pressed(..)
    

    Dheerendra
    @Community Service
    Certified Qt Specialist
    http://www.pthinks.com

    JonBJ 1 Reply Last reply
    1
    • dheerendraD dheerendra

      Did you get a chance to look other set of signals like.

      currentItemChanged(..)
      clicked(..)
      entered(..)
      pressed(..)
      
      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by
      #5

      @dheerendra
      Yep, I looked through all those. None of them pick up, e.g., terminating editing, at least, so no good....

      1 Reply Last reply
      0
      • dheerendraD Offline
        dheerendraD Offline
        dheerendra
        Qt Champions 2022
        wrote on last edited by
        #6

        terminatingEditing has to be custom. You have no choice other the your own delegate :)

        Dheerendra
        @Community Service
        Certified Qt Specialist
        http://www.pthinks.com

        JonBJ 1 Reply Last reply
        0
        • dheerendraD dheerendra

          terminatingEditing has to be custom. You have no choice other the your own delegate :)

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

          @dheerendra
          Yep, that's fine, as I wrote to @VRonin above, I am presently having a go at his code (converted to Python/PyQt!) to get me going....

          1 Reply Last reply
          0
          • D Offline
            D Offline
            DyraSan
            wrote on last edited by DyraSan
            #8

            Hey, I am newbie

            and I want to know how to edit a QListWidget item without removing it to edit and adding back?

            thanks,

            Kissanime

            1 Reply Last reply
            0
            • VRoninV Offline
              VRoninV Offline
              VRonin
              wrote on last edited by
              #9

              listWidget->item(i)->setData(role,data);

              "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

              1 Reply Last reply
              3
              • VRoninV VRonin

                That's because it's handled by the delegate.
                Subclass QStyledItemDelegate

                class SignalItemDelegate : public QStyledItemDelegate{
                Q_OBJECT
                Q_DISABLE_COPY(SignalItemDelegate)
                public:
                explicit SignalItemDelegate(QObject* parent = Q_NULLPTR):QStyledItemDelegate(parent){
                QObject::connect(this,&SignalItemDelegate::closeEditor,this,&SignalItemDelegate::editFinished);
                }
                void setEditorData(QWidget *editor, const QModelIndex &index) const Q_DECL_OVERRIDE{
                editStarted();
                return QStyledItemDelegate::setEditorData(editor,index);
                }
                Q_SIGNALS:
                void editStarted();
                void editFinished();
                };
                

                And then call something like:

                SignalItemDelegate* delegate = new SignalItemDelegate(listWidget);
                QObject::connect(delegate,&SignalItemDelegate::editStarted,[](){qDebug("edit started")});
                QObject::connect(delegate,&SignalItemDelegate::editFinished,[](){qDebug("edit finished")});
                listWidget->setItemDelegate(delegate);
                
                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by JonB
                #10

                @VRonin
                OK, I have come up with the basics which I believe emulates/corresponds to your C++ as best I can. I now have a further question about something which you don't do in your example which I would like.

                First, I'll paste the guts of my Python/PyQt code. You'll see it's rather different in signals/slots/emits. This may help or hinder, I don't know, feel free to ignore if that's best.

                class JEditableListStyledItemDelegate(QtWidgets.QStyledItemDelegate):
                    # class variable for "editStarted" signal
                    editStarted = QtCore.pyqtSignal(name='editStarted')
                    # class variable for "editFinished" signal
                    editFinished = QtCore.pyqtSignal(name='editFinished')
                
                    def __init__(self, parent: QtCore.QObject=None):
                        super().__init__(parent)
                
                        self.closeEditor.connect(self.editFinished)
                
                    def setEditorData(self, editor: QtWidgets.QWidget, index: QtCore.QModelIndex):
                        self.editStarted.emit()
                        return super().setEditorData(editor, index)
                
                
                class JEditableListWidget(QtWidgets.QListWidget):
                    # class variable for "editStarted" signal
                    editStarted = QtCore.pyqtSignal(name='editStarted')
                    # class variable for "editFinished" signal
                    editFinished = QtCore.pyqtSignal(name='editFinished')
                
                    def __init__(self, parent: QtWidgets.QWidget=None):
                        super().__init__(parent)
                
                        styledItemDelegate = JEditableListStyledItemDelegate(self)
                        styledItemDelegate.editStarted.connect(self.editStarted)
                        styledItemDelegate.editFinished.connect(self.editFinished)
                        self.setItemDelegate(styledItemDelegate)
                
                

                The above "works". The JEditableListStyledItemDelegate emits its own editStarted/Finished signals. The JEditableListWidget "redirects" those signals to its own editStarted/Finished signals, for the outside world to slot onto. So far so good?

                Now, if you look at a QListWidget signal for an item like http://doc.qt.io/qt-5/qlistwidget.html#itemChanged, its signature is QListWidget::itemChanged(QListWidgetItem *item). Hence it sends to the outside world a parameter of the QListWidgetItem which has been changed. My editStarted/Finished signals should do the same.

                Now I get stuck as to how I'm supposed to do that.

                I start by changing my JEditableListWidget signals to:

                class JEditableListWidget(QtWidgets.QListWidget):
                    # class variable for "editStarted" signal, including item
                    editStarted = QtCore.pyqtSignal(QtWidgets.QListWidgetItem, name='editStarted')
                    # class variable for "editFinished" signal, including item
                    editFinished = QtCore.pyqtSignal(QtWidgets.QListWidgetItem, name='editFinished')
                

                The extra first parameter of QtWidgets.QListWidgetItem declares the signal as forwarding the item as a parameter.

                Now how do I pass that? I believe that (a) I will need a lambda for the signal and (b) I need to know what item is being edited. I think where I had:

                styledItemDelegate.editStarted.connect(self.editStarted)
                

                I now need something like:

                styledItemDelegate.editStarted.connect(lambda: self.editStarted(someItemWidget))
                

                [Actually I suspect it might be more like:

                styledItemDelegate.editStarted.connect(lambda: self.editStarted.emit(someItemWidget))
                

                ]
                Could you tell me:

                • Is this how you would do it in C++ (e.g. with a lambda)? (If not, I may be doing it wrong.) Could you show me your C++ for how you would do this and I will attempt to figure it to PyQt? (Also, I believe your code omitted an emit because I know that's a NO-OP in C++; but could you include it wherever it should be, because in PyQt you can see we have to use emit as a function.)

                • How do I calculate what the someItemWidget will be, from inside my JEditableListWidget?

                1 Reply Last reply
                0
                • VRoninV Offline
                  VRoninV Offline
                  VRonin
                  wrote on last edited by
                  #11

                  It's actually super easy.
                  In the delegate:

                  • add an argument of type QtCore.QModelIndex to the signals.
                  • remove self.closeEditor.connect(self.editFinished)
                  • change self.editStarted.emit() to self.editStarted.emit(index)
                  • add
                  def destroyEditor(self, editor: QtWidgets.QWidget, index: QtCore.QModelIndex):
                          self.editFinished.emit(index)
                          return super().destroyEditor(editor, index)
                  

                  Now in JEditableListWidget you can connect a slot that accepts a QtCore.QModelIndex. To find the corresponding QListWidgetItem you can just call item(index.row())

                  "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

                  JonBJ 2 Replies Last reply
                  4
                  • VRoninV VRonin

                    It's actually super easy.
                    In the delegate:

                    • add an argument of type QtCore.QModelIndex to the signals.
                    • remove self.closeEditor.connect(self.editFinished)
                    • change self.editStarted.emit() to self.editStarted.emit(index)
                    • add
                    def destroyEditor(self, editor: QtWidgets.QWidget, index: QtCore.QModelIndex):
                            self.editFinished.emit(index)
                            return super().destroyEditor(editor, index)
                    

                    Now in JEditableListWidget you can connect a slot that accepts a QtCore.QModelIndex. To find the corresponding QListWidgetItem you can just call item(index.row())

                    JonBJ Offline
                    JonBJ Offline
                    JonB
                    wrote on last edited by
                    #12

                    @VRonin
                    TVM. I'll implement next week. You're passing the QtCore.QModelIndex available in the JEditableListStyledItemDelegate class up the signal chain to indicate which QListWidgetItem was acted upon. I thought the JEditableListWidget class would know which item in the list was being edited, but seemingly not?

                    1 Reply Last reply
                    0
                    • VRoninV VRonin

                      It's actually super easy.
                      In the delegate:

                      • add an argument of type QtCore.QModelIndex to the signals.
                      • remove self.closeEditor.connect(self.editFinished)
                      • change self.editStarted.emit() to self.editStarted.emit(index)
                      • add
                      def destroyEditor(self, editor: QtWidgets.QWidget, index: QtCore.QModelIndex):
                              self.editFinished.emit(index)
                              return super().destroyEditor(editor, index)
                      

                      Now in JEditableListWidget you can connect a slot that accepts a QtCore.QModelIndex. To find the corresponding QListWidgetItem you can just call item(index.row())

                      JonBJ Offline
                      JonBJ Offline
                      JonB
                      wrote on last edited by JonB
                      #13

                      @VRonin
                      Well, I followed your principle of having the QStyledItemDelegate emit signals with the QModelIndex as a parameter.

                      I diverged from yours slightly. Given that I'm now overriding destroyEditor() so as to access the index, it seems to me that I might as well be consistent and override createEditor() for beginning editing. So the following two overrides:

                      class JEditableListStyledItemDelegate(QtWidgets.QStyledItemDelegate):
                          # class variable for "editStarted" signal, with QModelIndex parameter
                          editStarted = QtCore.pyqtSignal(QtCore.QModelIndex, name='editStarted')
                          # class variable for "editFinished" signal, with QModelIndex parameter
                          editFinished = QtCore.pyqtSignal(QtCore.QModelIndex, name='editFinished')
                      
                          def createEditor(self, parent: QtWidgets.QWidget, option: QtWidgets.QStyleOptionViewItem, index: QtCore.QModelIndex):
                              editor = super().createEditor(parent, option, index)
                              if editor is not None:
                                  self.editStarted.emit(index)
                              return editor
                      
                          def destroyEditor(self, editor: QtWidgets.QWidget, index: QtCore.QModelIndex):
                              self.editFinished.emit(index)
                              return super().destroyEditor(editor, index)
                      

                      The above seems to give me fairly reliable signals for what I want, e.g. disable other buttons for doing things to QListWidget (add row, delete row) while the user is editing a row.

                      Seem reasonable to you? Thanks for all your input.

                      VRoninV 1 Reply Last reply
                      2
                      • JonBJ JonB

                        @VRonin
                        Well, I followed your principle of having the QStyledItemDelegate emit signals with the QModelIndex as a parameter.

                        I diverged from yours slightly. Given that I'm now overriding destroyEditor() so as to access the index, it seems to me that I might as well be consistent and override createEditor() for beginning editing. So the following two overrides:

                        class JEditableListStyledItemDelegate(QtWidgets.QStyledItemDelegate):
                            # class variable for "editStarted" signal, with QModelIndex parameter
                            editStarted = QtCore.pyqtSignal(QtCore.QModelIndex, name='editStarted')
                            # class variable for "editFinished" signal, with QModelIndex parameter
                            editFinished = QtCore.pyqtSignal(QtCore.QModelIndex, name='editFinished')
                        
                            def createEditor(self, parent: QtWidgets.QWidget, option: QtWidgets.QStyleOptionViewItem, index: QtCore.QModelIndex):
                                editor = super().createEditor(parent, option, index)
                                if editor is not None:
                                    self.editStarted.emit(index)
                                return editor
                        
                            def destroyEditor(self, editor: QtWidgets.QWidget, index: QtCore.QModelIndex):
                                self.editFinished.emit(index)
                                return super().destroyEditor(editor, index)
                        

                        The above seems to give me fairly reliable signals for what I want, e.g. disable other buttons for doing things to QListWidget (add row, delete row) while the user is editing a row.

                        Seem reasonable to you? Thanks for all your input.

                        VRoninV Offline
                        VRoninV Offline
                        VRonin
                        wrote on last edited by
                        #14

                        @JonB said in QListWidget item editing:

                        Given that I'm now overriding destroyEditor() so as to access the index, it seems to me that I might as well be consistent and override createEditor() for beginning editing.

                        Only doubt I have is if the delegate recycles the editor. Try going from editing 1 cell to editing another one directly and see if both create and destroy are called or it just calls setEditorData

                        "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

                        JonBJ 1 Reply Last reply
                        1
                        • VRoninV VRonin

                          @JonB said in QListWidget item editing:

                          Given that I'm now overriding destroyEditor() so as to access the index, it seems to me that I might as well be consistent and override createEditor() for beginning editing.

                          Only doubt I have is if the delegate recycles the editor. Try going from editing 1 cell to editing another one directly and see if both create and destroy are called or it just calls setEditorData

                          JonBJ Offline
                          JonBJ Offline
                          JonB
                          wrote on last edited by JonB
                          #15

                          @VRonin
                          OK, thanks! You should have said that concern was why you had overridden different/"inconsistent" methods, I had no idea why! Tried with direct click to edit another item, all is well, does call destroy and then create.

                          So I shall mark what I did as the solution to my original question. TVM.

                          P.S.
                          Your Xmas hat looks good. But a lot of others are also wearing them...! :)

                          mrjjM VRoninV 2 Replies Last reply
                          1
                          • JonBJ JonB

                            @VRonin
                            OK, thanks! You should have said that concern was why you had overridden different/"inconsistent" methods, I had no idea why! Tried with direct click to edit another item, all is well, does call destroy and then create.

                            So I shall mark what I did as the solution to my original question. TVM.

                            P.S.
                            Your Xmas hat looks good. But a lot of others are also wearing them...! :)

                            mrjjM Offline
                            mrjjM Offline
                            mrjj
                            Lifetime Qt Champion
                            wrote on last edited by
                            #16

                            @JonB said in QListWidget item editing:

                            Your Xmas hat looks good. But a lot of others are also wearing them...! :)

                            Well that is is on purpose :)

                            1 Reply Last reply
                            1
                            • JonBJ JonB

                              @VRonin
                              OK, thanks! You should have said that concern was why you had overridden different/"inconsistent" methods, I had no idea why! Tried with direct click to edit another item, all is well, does call destroy and then create.

                              So I shall mark what I did as the solution to my original question. TVM.

                              P.S.
                              Your Xmas hat looks good. But a lot of others are also wearing them...! :)

                              VRoninV Offline
                              VRoninV Offline
                              VRonin
                              wrote on last edited by
                              #17

                              @JonB said in QListWidget item editing:

                              Your Xmas hat looks good

                              All credit goes to @mrjj

                              "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

                              1 Reply Last reply
                              1

                              • Login

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