Hello,

This is my first post so please be gentle.

I am having trouble getting keyPressEvents in a QGraphicsItem to work. What I have is a QDialog that builds (in the QDialog constructor) a QGraphicsView, creates a QGraphicsScene, initializes two QGraphicsItems (one is a pixmap the other is a sort of "cursor" that is displayed on top of the pixmap at various locations) then places the items in the scene and then sets the scene in the view. I then set the focus to the "cursor" object by setting setFlags( IsFocusable ) and calling Item.setFocus().

I have overridden the QKeyEvent method in my cursor and am looking for the 'N' key, but it doesn't show up.

I appreciate any help you may give as I don't have much hair left...

Here is some c++ code (I'm still learning c++ and probably will be for quite some time)...

Qt Code: 
  1. // imap_cal_cursor.h
  2. #include <QGraphicsItem>
  3. #include <QObject>
  4.  
  5. class CImapCalCursor : public QObject, public QGraphicsItem
  6. {
  7.     Q_OBJECT
  8.  
  9. public:
  10.     CImapCalCursor();
  11.     void keyPressEvent( QKeyEvent *event );
  12. }
  13.  
  14.  
  15. //imap_cal_cursor.cpp
  16. #include "imap_cal_cursor.h"
  17.  
  18. #include <QGraphicsScene>
  19. #include <QPainter>
  20. #include <QStyleOption>
  21. #include <QKeyEvent>
  22.  
  23. #include "syslog.h"
  24.  
  25. CImapCalCursor::CImapCalCursor() : QObject(), QGraphicsItem()
  26. {
  27. }
  28.  
  29. void CImapCalCursor::keyPressEvent( QKeyEvent *event )
  30. {
  31.     switch (event->key()) {
  32.         case Qt::Key_N:
  33.             syslog( LOG_DEBUG, "DEBUG: Received Key_N event" );
  34.             break;
  35.     }
  36. }
  37.  
  38.  
  39. // calibration_dialog.h
  40. #include <QDialog>
  41. #include <QDialogButtonBox>
  42. #include "imap_cal_image.h"
  43. #include "imap_cal_cursor.h"
  44.  
  45. class CCalibration : public QDialog
  46. {
  47.     Q_OBJECT
  48.  
  49. public:
  50.     QDialogButtonBox *buttonBox;
  51.     QGraphicsView *graphix_area;
  52.  
  53. protected:
  54.     class CImapCalImage Image;
  55.     class CImapCalCursor cur;
  57.     QList< QPoint > list;
  58.     int   current_list_index;
  59.     QGraphicsPixmapItem *pixmapItem;
  60.  
  61. public:
  62.   CCalibration( QWidget * parent = 0, PEZG_COMMBLK EZGSharedMemPtr = NULL );
  63. };
  64.  
  65.  
  66. //calibration_dialog.cpp
  67. #include <QtGui>
  68. #include <QColor>
  69.  
  70. #include "calibration_dialog.h"
  71. #include "syslog.h"
  72.  
  73. CCalibration::CCalibration(QWidget * parent, PEZG_COMMBLK EZGSharedMemPtr )
  74.     : QDialog(parent)
  75. {
  76.     PIM_DIGBUFFER SourceImagePtr;
  77.     imageHeader   *SourceImageHeaderPtr;
  78.     unsigned char *SourceImageDataPtr;
  79.  
  80.     SourceImagePtr = &EZGSharedMemPtr->sImProcDigBuffer;
  81.     SourceImageHeaderPtr = &SourceImagePtr->Header;
  82.     SourceImageDataPtr = SourceImagePtr->image;
  83.  
  84.     setObjectName(QString::fromUtf8("Calibration_Dialog"));
  85.     buttonBox = new QDialogButtonBox( this );
  86.     buttonBox->setObjectName(QString::fromUtf8("buttonBox"));
  87.     buttonBox->setGeometry(QRect(400, 630, 161, 32));
  88.     buttonBox->setOrientation(Qt::Horizontal);
  89.     buttonBox->setStandardButtons(QDialogButtonBox::Cancel|QDialogButtonBox::NoButton|QDialogButtonBox::Ok);
  90.  
  91.     graphix_area = new QGraphicsView( this );
  92.     graphix_area->setObjectName(QString::fromUtf8("graphix_area"));
  93.     graphix_area->setGeometry(QRect(20, 40, 951, 571));
  94.     graphix_area->setCacheMode(QGraphicsView::CacheBackground);
  95.     graphix_area->setRenderHint(QPainter::Antialiasing);
  96.  
  97.     Scene = new QGraphicsScene( this );
  98.  
  99.     Image = CImapCalImage( SourceImageDataPtr, SourceImageHeaderPtr->imWidth, SourceImageHeaderPtr->imHeight, QImage::Format_Indexed8 );
  100.     Image.GenerateColorMap();
  101.     pixmapItem = Scene->addPixmap( QPixmap::fromImage( Image ) );
  102.  
  103.     list = Image.ScanForPoints();
  104.     if( list.isEmpty() || list.size() == 0 ) {
  105.         syslog( LOG_ERR, "ERROR: ScanForPoints returned empty list" );
  106.         current_list_index = -1;
  107.     }
  108.     else {
  109.         current_list_index = 0;
  110.         Scene->addItem( &cur );
  111.         cur.setZValue( 10 );
  112.         cur.setPos( pixmapItem->mapToParent( list[ current_list_index ] ) );
  113.         cur.setFlag( QGraphicsItem::ItemIsFocusable );
  114.     }
  115.  
  116.     graphix_area->setScene( Scene );
  117.     Scene->setFocusItem( &cur );
  118.  
  119.     QSize size(988, 684);
  120.     size = size.expandedTo(minimumSizeHint());
  121.     resize(size);
  122. }
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