Hi all,

I have the following question: I want to drag an item from a list widget to a graphics view and want to show something on the graphics view when the drop ended. For this I have done the regular work, It works, please see the code below. However I have the following question: I would like to show the thingie on the graphics view exactly where the drop ended... and for this I need your help. Seems the dropEvent (and the dragMove event) are not getting the required coordinates ... Can you hint me towards a solution: I want to place the "itm" object exactly where the mouse drag drop ended. (Don't mind the Version class, has nothing to do with this)

Thanks.
f

Code and out below:

Qt Code: 
  1. class ERGraphicsScene : public QGraphicsScene
  2. {
  3. public:
  4.     ERGraphicsScene(QWidget* parent, Version* v) : QGraphicsScene(parent), itm(0), m_version(v), lastX(-1), lastY(-1)
  5.     {
  6.         // to mark the centre of the view
  7.         addLine(0, -10, 0, 10);
  8.         addLine(-10, 0, 10, 0);
  9.     }
  10.  
  11.     void setLastCoords(int x, int y)
  12.     {
  13.         if(x != 0) lastX = x;
  14.         if(y != 0) lastY = y;
  15.  
  16.  
  17.         if(lastX != 0 & &lastY != 0 && lastX != -1  && lastY != -1 && itm != 0)
  18.         {
  19.             qDebug() << "setLastCoords: X=" << lastX << " Y=" << lastY;
  20.  
  21.             itm->setX(lastX);
  22.             itm->setY(lastY);
  23.             addItem(itm);
  24.             itm = 0;
  25.         }
  26.     }
  27.  
  28. protected:
  29.     virtual void dropEvent ( QGraphicsSceneDragDropEvent * event )
  30.     {
  31.         QString tabName = event->mimeData()->text();
  32.         event->acceptProposedAction();
  33.  
  34.         itm = m_version->getTable(tabName)->prepareDiagramEntity(event->pos().x(), event->pos().y());
  35.         setLastCoords(event->pos().x(), event->pos().y());
  36.     }
  37.  
  38.     void dragEnterEvent ( QGraphicsSceneDragDropEvent * event )
  39.     {
  40.         qDebug() << "GraphicsScene::dragEnter : X=" << event->pos().x() << " Y=" << event->pos().y();
  41.         event->acceptProposedAction();
  42.     }
  43.  
  44.     void dragMoveEvent ( QGraphicsSceneDragDropEvent * event )
  45.     {
  46.         qDebug() << "GraphicsScene::dragMove : X=" << event->pos().x() << " Y=" << event->pos().y();
  47.         event->acceptProposedAction();
  48.         int x = event->pos().x();
  49.         int y = event->pos().y();
  50.         setLastCoords(x,y);
  51.     }
  52.  
  53.     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *event)
  54.     {
  55.         qDebug() << "ERGraphicsScene::mouseMove : X=" << event->pos().x() << " Y=" << event->pos().y();
  56.         setLastCoords(event->pos().x(), event->pos().y());
  57.     }
  58.  
  59.     virtual void mouseReleaseEvent ( QGraphicsSceneMouseEvent * event )
  60.     {
  61.         qDebug() << "GraphicsScene::mouseRelease: X=" << event->pos().x() << " Y=" << event->pos().y();
  62.     }
  63.  
  64. private:
  66.     Version* m_version;
  67.     int lastX;
  68.     int lastY;
  69.  
  70. };
  71.  
  72. class ERGraphicsView : public QGraphicsView
  73. {
  74. public:
  75.  
  76.     ERGraphicsView(QWidget* parent, Version* v) : QGraphicsView(parent)
  77.     {
  78.         setAcceptDrops(true);
  79.         scene = new ERGraphicsScene(this, v);
  80.         setScene(scene);
  81.     }
  82.  
  83.  
  84.     void setLastCoords(int x, int y)
  85.     {
  86.         scene->setLastCoords(x, y);
  87.     }
  88.  
  89. protected:
  90.  
  91.     virtual void mouseMoveEvent(QMouseEvent *event)
  92.     {
  93.         qDebug() << "GraphicsView::mouseMove : X=" << event->pos().x() << " Y=" << event->pos().y();
  94.         scene->setLastCoords(event->pos().x(), event->pos().y());
  95.     }
  96.  
  97. private:
  98.  
  99.     ERGraphicsScene* scene;
  100.  
  101. };
  102.  
  103. class TableListWidget : public QListWidget
  104. {
  105. public:
  106.  
  107.     TableListWidget(QWidget* parent, ERGraphicsView* associatedGrView) : QListWidget(parent), grv(associatedGrView)
  108.     {
  109.         setDragEnabled(true);
  110.     }
  111.  
  112. protected:
  113.     virtual void dragEnterEvent(QDragEnterEvent *e) 
  114.     { 
  115.         e->accept(); 
  116.     }
  117.  
  118.     virtual void dragMoveEvent(QDragMoveEvent *event)
  119.     {
  120.         qDebug() << "TabListWidget::dragMove : X=" << event->pos().x() << " Y=" << event->pos().y();
  121.         event->accept();
  122.     }
  123.  
  124.     virtual void dropEvent(QDropEvent *event)
  125.     {
  126.         event->accept();
  127.     }
  128.  
  129.     virtual void mouseMoveEvent(QMouseEvent *event)
  130.     {
  131.         if (!(event->buttons() & Qt::LeftButton)) return;
  132.         if (currentItem() == NULL) return;
  133.  
  134.         QDrag *drag = new QDrag(this);
  135.         QMimeData *mimeData = new QMimeData;
  136.  
  137.         // mime stuff
  138.         mimeData->setText(currentItem()->text());
  139.         drag->setMimeData(mimeData);
  140.         drag->setPixmap(IconFactory::getTablesIcon().pixmap(16,16));
  141.  
  142.         // start drag
  143.         drag->start(Qt::CopyAction | Qt::MoveAction);
  144.     }
  145. private:
  146.     ERGraphicsView* grv;
  147. };
  148.  
  149. DiagramForm::DiagramForm(Version* v, QWidget *parent) : QWidget(parent), ui(new Ui::DiagramForm), ver(v)
  150. {
  151.  
  152.     ui->setupUi(this);
  153.  
  154.     ERGraphicsView *graphicsView;
  155.     graphicsView = new ERGraphicsView(this, v);
  156.     graphicsView->setObjectName(QString::fromUtf8("graphicsView"));
  157.     graphicsView->setDragMode(QGraphicsView::RubberBandDrag);
  158.     graphicsView->setAcceptDrops(true);
  159.  
  160.     TableListWidget *lstTables;
  161.     lstTables = new TableListWidget(ui->groupBox, graphicsView);
  162.     lstTables->setObjectName(QString::fromUtf8("lstTables"));
  163.     QSizePolicy sizePolicy(QSizePolicy::Fixed, QSizePolicy::Expanding);
  164.     sizePolicy.setHorizontalStretch(0);
  165.     sizePolicy.setVerticalStretch(0);
  166.     sizePolicy.setHeightForWidth(lstTables->sizePolicy().hasHeightForWidth());
  167.     lstTables->setSizePolicy(sizePolicy);
  168.     lstTables->setDragDropMode(QAbstractItemView::DragDrop);
  169.  
  170.     ui->verticalLayout_2->addWidget(lstTables);
  171.  
  172.     ui->horizontalLayout->addWidget(graphicsView);
  173.  
  174.     for(int i=0; i<v->getTables().size(); i++)
  175.     {
  176.         QListWidgetItem* qlwi = new QListWidgetItem(v->getTables()[i]->getName(), lstTables);
  177.         qlwi->setIcon(IconFactory::getTablesIcon());
  178.     }
  179. }
  180.  
  181. DiagramForm::~DiagramForm()
  182. {
  183.     delete ui;
  184. }
  185.  
  186. void DiagramForm::changeEvent(QEvent *e)
  187. {
  188.     QWidget::changeEvent(e);
  189.     switch (e->type()) {
  190.     case QEvent::LanguageChange:
  191.         ui->retranslateUi(this);
  192.         break;
  193.     default:
  194.         break;
  195.     }
  196. }
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and the output:

TabListWidget::dragMove : X= 197 Y= 46
TabListWidget::dragMove : X= 199 Y= 46
TabListWidget::dragMove : X= 201 Y= 45
TabListWidget::dragMove : X= 203 Y= 45
TabListWidget::dragMove : X= 206 Y= 45
TabListWidget::dragMove : X= 208 Y= 45
TabListWidget::dragMove : X= 210 Y= 45
TabListWidget::dragMove : X= 213 Y= 45
TabListWidget::dragMove : X= 216 Y= 45
TabListWidget::dragMove : X= 218 Y= 45
TabListWidget::dragMove : X= 220 Y= 45
TabListWidget::dragMove : X= 222 Y= 45
TabListWidget::dragMove : X= 224 Y= 45
TabListWidget::dragMove : X= 227 Y= 45
TabListWidget::dragMove : X= 229 Y= 44
TabListWidget::dragMove : X= 231 Y= 44
TabListWidget::dragMove : X= 232 Y= 44
TabListWidget::dragMove : X= 234 Y= 44
TabListWidget::dragMove : X= 236 Y= 44
TabListWidget::dragMove : X= 237 Y= 44
TabListWidget::dragMove : X= 238 Y= 44
TabListWidget::dragMove : X= 239 Y= 44
TabListWidget::dragMove : X= 240 Y= 44
TabListWidget::dragMove : X= 241 Y= 44
TabListWidget::dragMove : X= 243 Y= 44
TabListWidget::dragMove : X= 244 Y= 44
TabListWidget::dragMove : X= 245 Y= 44
TabListWidget::dragMove : X= 246 Y= 44
TabListWidget::dragMove : X= 248 Y= 44
TabListWidget::dragMove : X= 250 Y= 44
TabListWidget::dragMove : X= 252 Y= 44
TabListWidget::dragMove : X= 253 Y= 44
GraphicsScene::dragEnter : X= 0 Y= 0
GraphicsScene::dragMove : X= 0 Y= 0
GraphicsScene::dragMove : X= 0 Y= 0
GraphicsScene::dragMove : X= 0 Y= 0
GraphicsScene::dragMove : X= 0 Y= 0
GraphicsScene::dragMove : X= 0 Y= 0


Here I dropped the object and the dropEvent didn't got any usable coordinates ...