how to use dragMove()..

[sar_van81]

hi,

i had written an application in which i use drag and drop concept.in that use dragCopy for dragging the items. but i need move the item itself instead of copying. i tried using dragMove() function instead of dragCopy(). but i could not move the item. the following is my code:

class drag : public QLabel
{
	public:
    		drag(QWidget* parent=0, const char* name=0);
	protected:
		void mousePressEvent( QMouseEvent * );	
};
 
drag::drag(QWidget * parent,const char * name):
	QLabel(parent,name)
{
 
}
 
void drag::mousePressEvent( QMouseEvent * a )
{
    QDragObject *drobj;
    if ( pixmap() )
	drobj = new QImageDrag( pixmap()->convertToImage(), this );
    drobj->dragMove();
}

class drag : public QLabel
{
	public:
    		drag(QWidget* parent=0, const char* name=0);
	protected:
		void mousePressEvent( QMouseEvent * );	
};

drag::drag(QWidget * parent,const char * name):
	QLabel(parent,name)
{

}

void drag::mousePressEvent( QMouseEvent * a )
{
    QDragObject *drobj;
    if ( pixmap() )
	drobj = new QImageDrag( pixmap()->convertToImage(), this );
    drobj->dragMove();
}

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is this correct ? if no means can anyone correct me ?

thanks in advance,

[rajesh]

try this:

void drag::mousePressEvent(QMouseEvent *event)
{
 if (event->button() == Qt::LeftButton)
 {
  QMimeData *mimeData = new QMimeData;
  mimeData->setText("myDrageLabel");
  QDrag *drag = new QDrag(this);
  drag->setMimeData(mimeData);
  Qt::DropAction dropAction = drag->start(Qt::CopyAction | Qt::MoveAction);
  if (dropAction == Qt::MoveAction) 
  {
   close();
   update();
  }
 }
}
in your base class, in which you are using drag object (say myWidget)
myWidget::myWidget(QWidget *parent) : 
                                 QWidget(parent)
{
 setAcceptDrops(true);
 ...
}
void myWidget::dragEnterEvent(QDragEnterEvent *event)
{
 if (event->mimeData()->hasText())
 {
  event->acceptProposedAction();
 }
 else
 {
  event->ignore();
 }
}
void myWidget::dropEvent(QDropEvent *event)
{
 if (event->mimeData()->hasText()) 
 {
  //QString plainText = event->mimeData()->text();
  QPoint dropPos  = event->pos();
  QDragObject *drobj;    
  if ( pixmap() )    
   drobj = new QImageDrag( pixmap()->convertToImage(), this );    
  drobj->move(dropPos);
 
  drobj->show();
 
  if (children().contains(event->source())) 
  {
   event->setDropAction(Qt::MoveAction);
   event->accept();
  } 
  else 
  {
   event->acceptProposedAction();
  }
 }
 else 
 {
  event->ignore();
 }
}

void drag::mousePressEvent(QMouseEvent *event)
{
 if (event->button() == Qt::LeftButton)
 {
  QMimeData *mimeData = new QMimeData;
  mimeData->setText("myDrageLabel");
  QDrag *drag = new QDrag(this);
  drag->setMimeData(mimeData);
  Qt::DropAction dropAction = drag->start(Qt::CopyAction | Qt::MoveAction);
  if (dropAction == Qt::MoveAction) 
  {
   close();
   update();
  }
 }
}
in your base class, in which you are using drag object (say myWidget)
myWidget::myWidget(QWidget *parent) : 
                                 QWidget(parent)
{
 setAcceptDrops(true);
 ...
}
void myWidget::dragEnterEvent(QDragEnterEvent *event)
{
 if (event->mimeData()->hasText())
 {
  event->acceptProposedAction();
 }
 else
 {
  event->ignore();
 }
}
void myWidget::dropEvent(QDropEvent *event)
{
 if (event->mimeData()->hasText()) 
 {
  //QString plainText = event->mimeData()->text();
  QPoint dropPos  = event->pos();
  QDragObject *drobj;    
  if ( pixmap() )    
   drobj = new QImageDrag( pixmap()->convertToImage(), this );    
  drobj->move(dropPos);
 
  drobj->show();
 
  if (children().contains(event->source())) 
  {
   event->setDropAction(Qt::MoveAction);
   event->accept();
  } 
  else 
  {
   event->acceptProposedAction();
  }
 }
 else 
 {
  event->ignore();
 }
}

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[sar_van81]

Hi Rajesh,

thanks for your code. but unfortunately i'm using older version of qt(qt-3.3.5). in that i dont have QMimeData etc. but let me go through the code and try to adapt with teh functions in qt-3.3.5. but i think the problem in my code was that i used QPixmap::load() function to display the image. and then drag this image to the drop widget. this is my code:

static void addStuff( QWidget * parent, bool image, bool secret = FALSE )
{
  QVBoxLayout * tll = new QVBoxLayout( parent);
if(image)
  {
	drag *drg = new drag(parent);
	drag *drg1 = new drag(parent);
	tll->addWidget( drg );
	tll->addWidget( drg1 );
	QPixmap stuff;
	QPixmap stuff1;
	if(stuff.load( "trolltech.bmp" ));    ----i think this caused my image not to be moved---
	itemname[0]=1;	
	stuff1.load( "butterfly.png" );
	drg->setPixmap( stuff );
	drg1->setPixmap( stuff1 );
  }
  else
	{	
	drop *drp= new drop(parent);
	drop *drp1= new drop(parent);
	tll->addWidget( drp );
	tll->addWidget( drp1 );
	drp->setText("Drop the items");
	drp->setFont(QFont("Helvetica",12));
	drp1->setText("Drag and Drop");
	drp1->setFont(QFont("Helvetica",12));
	}	
}

static void addStuff( QWidget * parent, bool image, bool secret = FALSE )
{
  QVBoxLayout * tll = new QVBoxLayout( parent);
if(image)
  {
	drag *drg = new drag(parent);
	drag *drg1 = new drag(parent);
	tll->addWidget( drg );
	tll->addWidget( drg1 );
	QPixmap stuff;
	QPixmap stuff1;
	if(stuff.load( "trolltech.bmp" ));    ----i think this caused my image not to be moved---
	itemname[0]=1;	
	stuff1.load( "butterfly.png" );
	drg->setPixmap( stuff );
	drg1->setPixmap( stuff1 );
  }
  else
	{	
	drop *drp= new drop(parent);
	drop *drp1= new drop(parent);
	tll->addWidget( drp );
	tll->addWidget( drp1 );
	drp->setText("Drop the items");
	drp->setFont(QFont("Helvetica",12));
	drp1->setText("Drag and Drop");
	drp1->setFont(QFont("Helvetica",12));
	}	
}

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.

thinking of using QIconview. any suggestions ?

[rajesh]

I dont know about Qpixmap::load. but in your previous code you creating a new object and not deleteing old object. so it will create a copy of new widget.
mainly whenever you create a new widget then delete or close old widget.