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Items in QGraphicsScene are not movable

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  • sanojsubranS Offline
    sanojsubranS Offline
    sanojsubran
    wrote on last edited by
    #2

    Try adding the following statement also,
    ellipse->setAcceptHoverEvents( true );

    1 Reply Last reply
    0
    • faiszalkhanF Offline
      faiszalkhanF Offline
      faiszalkhan
      wrote on last edited by
      #3

      Tried ellipse->setAcceptHoverEvents( true );

      Doesn't work.

      1 Reply Last reply
      0
      • sanojsubranS Offline
        sanojsubranS Offline
        sanojsubran
        wrote on last edited by sanojsubran
        #4

        Hi,

        ellipse = scene->addEllipse(100,100,100,100,blackpen,bluebrush);
        ellipse->setFlags(QGraphicsItem::ItemIsMovable);
        rect = scene->addRect(-10,50,100,100,blackpen,redbrush);
        rect->setFlags(QGraphicsItem::ItemIsMovable);

        I added these items to a custom graphics scene and the move operation works perfectly for me.

        Could you please share more info/code ?
        Also are you overriding the mouse events for the graphics scene class?

        Regards,
        San

        1 Reply Last reply
        1
        • faiszalkhanF Offline
          faiszalkhanF Offline
          faiszalkhan
          wrote on last edited by
          #5

          Hi, Yes I am overriding the mousePressEvent as follows. Whereas the constructor is empty.

          void Canvas::mousePressEvent(QGraphicsSceneMouseEvent *gevent)
          {

          /* Get the position of the mouse clicked */
          QPointF pressedPosition(gevent->scenePos());
          

          #ifdef DEBUG
          qDebug("Mouse has been pressed");

            qreal temp_x = gevent->scenePos().x();
            qDebug("The value of the Xcordinate for the mouse clicked is");
            qDebug()<<temp_x;
          
            qreal temp_y = gevent->scenePos().y();
            qDebug("The value of the Ycordinate for the mouse clicked is");
            qDebug()<<temp_y;
          

          #endif

          /* Create the state here */
          srstate = new StateItem(pressedPosition);
          mainWindowPtr->scene->addItem(srstate);
          srstate->setFlags(QGraphicsItem::ItemIsMovable);
          

          }

          Thanks!

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          0
          • sanojsubranS Offline
            sanojsubranS Offline
            sanojsubran
            wrote on last edited by
            #6

            Try adding the statement QGraphicsScene::mousePressEvent( event ); before the end of the function

            faiszalkhanF 1 Reply Last reply
            3
            • sanojsubranS sanojsubran

              Try adding the statement QGraphicsScene::mousePressEvent( event ); before the end of the function

              faiszalkhanF Offline
              faiszalkhanF Offline
              faiszalkhan
              wrote on last edited by
              #7

              @sanojsubran I tried that but it results in a compilation error.

              mrjjM 1 Reply Last reply
              0
              • faiszalkhanF faiszalkhan

                @sanojsubran I tried that but it results in a compilation error.

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by
                #8

                @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 1 Reply Last reply
                1
                • 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.

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                            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);

                                }

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                                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

                                        1 Reply Last reply
                                        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
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