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  4. Items in QGraphicsScene are not movable

Items in QGraphicsScene are not movable

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  • mrjjM mrjj

    @faiszalkhan
    Hi
    Can you list that error ?
    Since its the base class that do the actual moving,
    its critical to call it so lets find out what was wrong ?

    faiszalkhanF Offline
    faiszalkhanF Offline
    faiszalkhan
    wrote on last edited by faiszalkhan
    #9

    @mrjj @sanojsubran It was my bad. The solution worked. However I'm not very sure as to what we did there :(

    1 Reply Last reply
    0
    • faiszalkhanF Offline
      faiszalkhanF Offline
      faiszalkhan
      wrote on last edited by faiszalkhan
      #10

      The problem is not completely solved. StateItem is a custom graphics item which inherits QGraphicsItem.
      The constructor of StateItem is as shown below,

      StateItem::StateItem(QPointF pos)
      {
      /* Get the position from the caller */
      drawPos = new QPointF(pos.x(), pos.y());

      //TODO: Set item as movable
      setFlags(QGraphicsItem::ItemIsMovable);

      }

      This graphics Item is displayed on the scene but still is not movable.

      Please help!
      Thanks!

      1 Reply Last reply
      0
      • SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #11

        Hi,

        Your original problem was that by not calling the base class method implementation, you don't get the behaviour from the base class.

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

        1 Reply Last reply
        2
        • faiszalkhanF Offline
          faiszalkhanF Offline
          faiszalkhan
          wrote on last edited by
          #12

          Since I am inheriting the QGraphicsItem in StateItem to create custom shape. Am I missing out something for setFlags(QGraphicsItem::ItemIsMovable); in the constructor to not work ?

          Thanks

          1 Reply Last reply
          0
          • mrjjM Offline
            mrjjM Offline
            mrjj
            Lifetime Qt Champion
            wrote on last edited by
            #13

            Hi
            You might need
            setFlag(QGraphicsItem::ItemIsMovable);
            setFlag(QGraphicsItem::ItemIsSelectable);

            If we look at
            http://doc.qt.io/qt-5/qtwidgets-graphicsview-diagramscene-example.html

            It all it does to flag the items.

            faiszalkhanF 1 Reply Last reply
            1
            • mrjjM mrjj

              Hi
              You might need
              setFlag(QGraphicsItem::ItemIsMovable);
              setFlag(QGraphicsItem::ItemIsSelectable);

              If we look at
              http://doc.qt.io/qt-5/qtwidgets-graphicsview-diagramscene-example.html

              It all it does to flag the items.

              faiszalkhanF Offline
              faiszalkhanF Offline
              faiszalkhan
              wrote on last edited by
              #14

              @mrjj said in Items in QGraphicsScene are not movable:

              setFlag(QGraphicsItem::ItemIsMovable);
              setFlag(QGraphicsItem::ItemIsSelectable);

              Hi @mrjj , tried the same but still not working.

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

                Ok. cant tell what is wrong then.
                You might have overridden a virtual and forgot to call base class.

                Have a look at the diagram sample and see if can spot anything you
                did different.

                Or try the StateItem in a default scene/view.

                faiszalkhanF 1 Reply Last reply
                0
                • mrjjM mrjj

                  Ok. cant tell what is wrong then.
                  You might have overridden a virtual and forgot to call base class.

                  Have a look at the diagram sample and see if can spot anything you
                  did different.

                  Or try the StateItem in a default scene/view.

                  faiszalkhanF Offline
                  faiszalkhanF Offline
                  faiszalkhan
                  wrote on last edited by
                  #16

                  @mrjj I just have the constructor, paint function and bounding rect. The file is as follows,

                  StateItem::StateItem(QPointF pos)
                  {

                  /* Get the position from the caller */
                  drawPos = new QPointF(pos.x(), pos.y());
                  
                  //TODO: Set item as movable
                  

                  // setFlags(QGraphicsItem::ItemIsFocusable);
                  // setFlags(QGraphicsItem::ItemIsSelectable);
                  setFlags(QGraphicsItem::ItemIsMovable);

                  // QGraphicsItem::QGraphicsItem();
                  }

                  QRectF StateItem::boundingRect() const
                  {
                  //TODO: Return a rectangle of calculated size
                  qreal penWidth = 1;
                  return QRectF(-10 - penWidth / 2, -10 - penWidth / 2,
                  20 + penWidth, 20 + penWidth);

                  }

                  /* Explicit call to this function is not required */
                  void StateItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget widget)
                  {
                  /
                  Set the pen */
                  QPen blackpen(Qt::black);
                  blackpen.setWidth(2);
                  painter->setPen(blackpen);

                  /* Set colour of the state */
                  QColor statecolor(229,231,233);
                  QBrush statebrush(statecolor);
                  painter->setBrush(statebrush);
                  
                  /* Draw state item */
                  painter->drawRoundedRect(drawPos->x(),drawPos->y(),100,50,8,8); //x,y,width,height,xradius,yradius
                  
                  QPoint p(drawPos->x(),(drawPos->y() + 10));
                  QPoint q((drawPos->x() + 100), (drawPos->y() + 10));
                  QLine stateLine(p,q);
                  painter->drawLine(stateLine);
                  

                  // QGraphicsItem::paint(painter,option,widget);

                  }

                  1 Reply Last reply
                  0
                  • mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by
                    #17

                    Hi
                    Dont it need to be selectable to be moveable ?
                    It all seems fine
                    try use the DiagramTextItem from the diagram sample (its available directly in Creator)

                    If that cant move, it means its your view or scene.

                    //! [0]
                    DiagramTextItem::DiagramTextItem(QGraphicsItem *parent)
                        : QGraphicsTextItem(parent)
                    {
                        setFlag(QGraphicsItem::ItemIsMovable); // BOTH 
                        setFlag(QGraphicsItem::ItemIsSelectable);
                    }
                    //! [0]
                    
                    //! [1]
                    QVariant DiagramTextItem::itemChange(GraphicsItemChange change,
                                         const QVariant &value)
                    {
                        if (change == QGraphicsItem::ItemSelectedHasChanged)
                            emit selectedChange(this);
                        return value;
                    }
                    //! [1]
                    
                    //! [2]
                    void DiagramTextItem::focusOutEvent(QFocusEvent *event)
                    {
                        setTextInteractionFlags(Qt::NoTextInteraction);
                        emit lostFocus(this);
                        QGraphicsTextItem::focusOutEvent(event);
                    }
                    //! [2]
                    
                    //! [5]
                    void DiagramTextItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
                    {
                        if (textInteractionFlags() == Qt::NoTextInteraction)
                            setTextInteractionFlags(Qt::TextEditorInteraction);
                        QGraphicsTextItem::mouseDoubleClickEvent(event);
                    }
                    
                    faiszalkhanF 1 Reply Last reply
                    0
                    • mrjjM mrjj

                      Hi
                      Dont it need to be selectable to be moveable ?
                      It all seems fine
                      try use the DiagramTextItem from the diagram sample (its available directly in Creator)

                      If that cant move, it means its your view or scene.

                      //! [0]
                      DiagramTextItem::DiagramTextItem(QGraphicsItem *parent)
                          : QGraphicsTextItem(parent)
                      {
                          setFlag(QGraphicsItem::ItemIsMovable); // BOTH 
                          setFlag(QGraphicsItem::ItemIsSelectable);
                      }
                      //! [0]
                      
                      //! [1]
                      QVariant DiagramTextItem::itemChange(GraphicsItemChange change,
                                           const QVariant &value)
                      {
                          if (change == QGraphicsItem::ItemSelectedHasChanged)
                              emit selectedChange(this);
                          return value;
                      }
                      //! [1]
                      
                      //! [2]
                      void DiagramTextItem::focusOutEvent(QFocusEvent *event)
                      {
                          setTextInteractionFlags(Qt::NoTextInteraction);
                          emit lostFocus(this);
                          QGraphicsTextItem::focusOutEvent(event);
                      }
                      //! [2]
                      
                      //! [5]
                      void DiagramTextItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
                      {
                          if (textInteractionFlags() == Qt::NoTextInteraction)
                              setTextInteractionFlags(Qt::TextEditorInteraction);
                          QGraphicsTextItem::mouseDoubleClickEvent(event);
                      }
                      
                      faiszalkhanF Offline
                      faiszalkhanF Offline
                      faiszalkhan
                      wrote on last edited by
                      #18

                      @mrjj Dont it need to be selectable to be moveable ?

                      No, Only setting it as moveable also works. I have standard QGraphicsRectItem and QGraphicsEllipseItem also in the same scene which are moving. So I don't think its the view or the scene.

                      :'(

                      mrjjM 1 Reply Last reply
                      0
                      • faiszalkhanF faiszalkhan

                        @mrjj Dont it need to be selectable to be moveable ?

                        No, Only setting it as moveable also works. I have standard QGraphicsRectItem and QGraphicsEllipseItem also in the same scene which are moving. So I don't think its the view or the scene.

                        :'(

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

                        @faiszalkhan
                        Ok, there is something i dont see then. :)
                        if you provide both StateItem.h and cpp
                        i can try run it and see.

                        faiszalkhanF 1 Reply Last reply
                        0
                        • sanojsubranS Offline
                          sanojsubranS Offline
                          sanojsubran
                          wrote on last edited by
                          #20

                          Hi,

                          Comment your overriden paint method for StateItem and check whether it is working.

                          Also please tell how you are updating the variable "drawPos".

                          Regards,
                          San

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                          0
                          • mrjjM mrjj

                            @faiszalkhan
                            Ok, there is something i dont see then. :)
                            if you provide both StateItem.h and cpp
                            i can try run it and see.

                            faiszalkhanF Offline
                            faiszalkhanF Offline
                            faiszalkhan
                            wrote on last edited by faiszalkhan
                            #21
                            This post is deleted!
                            1 Reply Last reply
                            0
                            • faiszalkhanF Offline
                              faiszalkhanF Offline
                              faiszalkhan
                              wrote on last edited by
                              #22
                              This post is deleted!
                              1 Reply Last reply
                              0
                              • faiszalkhanF Offline
                                faiszalkhanF Offline
                                faiszalkhan
                                wrote on last edited by
                                #23

                                I had previously given a static bounding rect value as the previous implementation was static. Now that the value is dynamic I had not changed the contents of the bounding rect as the size has not changed from the previous implementation.

                                Making the changes in the bounding rect solved the problem.

                                Thanks a lot to @mrjj @sanojsubran @SGaist !

                                1 Reply Last reply
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