Drag and Drop (Simple) h3.fn,span.fn { margin-left: 1cm; text-indent: -1cm; } a:link { color: #004faf; text-decoration: none } a:visited { color: #672967; text-decoration: none } body { background: #ffffff; color: black; } --> Home | All Classes | Main Classes | Annotated | Grouped Classes | Functions Drag and Drop (Simple) This provides a very simple example of Qt's drag and drop functionality. For a more complete example see the Drag and Drop example. Header file: /**************************************************************************** ** $Id$ ** ** Copyright (C) 1992-2001 Trolltech AS. All rights reserved. ** ** This file is part of an example program for Qt. This example ** program may be used, distributed and modified without limitation. ** *****************************************************************************/ #include <qapplication.h> #include <qcursor.h> #include <qsplitter.h> #include <qlistbox.h> #include <qiconview.h> #include <qpixmap.h> class QDragEnterEvent; class QDragDropEvent; class DDListBox : public QListBox { Q_OBJECT public: DDListBox( QWidget * parent = 0, const char * name = 0, WFlags f = 0 ); // Low-level drag and drop void dragEnterEvent( QDragEnterEvent *evt ); void dropEvent( QDropEvent *evt ); void mousePressEvent( QMouseEvent *evt ); void mouseMoveEvent( QMouseEvent * ); private: int dragging; }; class DDIconViewItem : public QIconViewItem { public: DDIconViewItem( QIconView *parent, const QString& text, const QPixmap& icon ) : QIconViewItem( parent, text, icon ) {} DDIconViewItem( QIconView *parent, const QString &text ) : QIconViewItem( parent, text ) {} // High-level drag and drop bool acceptDrop( const QMimeSource *mime ) const; void dropped( QDropEvent *evt, const QValueList<QIconDragItem>& ); }; class DDIconView : public QIconView { Q_OBJECT public: DDIconView( QWidget * parent = 0, const char * name = 0, WFlags f = 0 ) : QIconView( parent, name, f ) {} // High-level drag and drop QDragObject *dragObject(); public slots: void slotNewItem( QDropEvent *evt, const QValueList<QIconDragItem>& list ); }; Implementation: /**************************************************************************** ** $Id$ ** ** Copyright (C) 1992-2001 Trolltech AS. All rights reserved. ** ** This file is part of an example program for Qt. This example ** program may be used, distributed and modified without limitation. ** *****************************************************************************/ #include "main.h" const char* red_icon[]={ "16 16 2 1", "r c red", ". c None", "................", "................", "..rrrrrrrrrrrr..", "..rrrrrrrrrrrr..", "..rrrrrrrrrrrr..", "..rrr......rrr..", "..rrr......rrr..", "..rrr......rrr..", "..rrr......rrr..", "..rrr......rrr..", "..rrr......rrr..", "..rrrrrrrrrrrr..", "..rrrrrrrrrrrr..", "..rrrrrrrrrrrr..", "................", "................"}; const char* blue_icon[]={ "16 16 2 1", "b c blue", ". c None", "................", "................", "..bbbbbbbbbbbb..", "..bbbbbbbbbbbb..", "..bbbbbbbbbbbb..", "..bbb......bbb..", "..bbb......bbb..", "..bbb......bbb..", "..bbb......bbb..", "..bbb......bbb..", "..bbb......bbb..", "..bbbbbbbbbbbb..", "..bbbbbbbbbbbb..", "..bbbbbbbbbbbb..", "................", "................"}; const char* green_icon[]={ "16 16 2 1", "g c green", ". c None", "................", "................", "..gggggggggggg..", "..gggggggggggg..", "..gggggggggggg..", "..ggg......ggg..", "..ggg......ggg..", "..ggg......ggg..", "..ggg......ggg..", "..ggg......ggg..", "..ggg......ggg..", "..gggggggggggg..", "..gggggggggggg..", "..gggggggggggg..", "................", "................"}; // ListBox -- low level drag and drop DDListBox::DDListBox( QWidget * parent, const char * name, WFlags f ) : QListBox( parent, name, f ) { setAcceptDrops( TRUE ); dragging = FALSE; } void DDListBox::dragEnterEvent( QDragEnterEvent *evt ) { if ( QTextDrag::canDecode( evt ) ) evt->accept(); } void DDListBox::dropEvent( QDropEvent *evt ) { QString text; if ( QTextDrag::decode( evt, text ) ) insertItem( text ); } void DDListBox::mousePressEvent( QMouseEvent *evt ) { QListBox::mousePressEvent( evt ); dragging = TRUE; } void DDListBox::mouseMoveEvent( QMouseEvent * ) { if ( dragging ) { QDragObject *d = new QTextDrag( currentText(), this ); d->dragCopy(); // do NOT delete d. dragging = FALSE; } } // IconViewIcon -- high level drag and drop bool DDIconViewItem::acceptDrop( const QMimeSource *mime ) const { if ( mime->provides( "text/plain" ) ) return TRUE; return FALSE; } void DDIconViewItem::dropped( QDropEvent *evt, const QValueList<QIconDragItem>& ) { QString label; if ( QTextDrag::decode( evt, label ) ) setText( label ); } // IconView -- high level drag and drop QDragObject *DDIconView::dragObject() { return new QTextDrag( currentItem()->text(), this ); } void DDIconView::slotNewItem( QDropEvent *evt, const QValueList<QIconDragItem>& ) { QString label; if ( QTextDrag::decode( evt, label ) ) { DDIconViewItem *item = new DDIconViewItem( this, label ); item->setRenameEnabled( TRUE ); } } int main( int argc, char *argv[] ) { QApplication app( argc, argv ); // Create and show the widgets QSplitter *split = new QSplitter(); DDIconView *iv = new DDIconView( split ); (void) new DDListBox( split ); app.setMainWidget( split ); split->resize( 600, 400 ); split->show(); // Set up the connection so that we can drop items into the icon view QObject::connect( iv, SIGNAL(dropped(QDropEvent*, const QValueList<QIconDragItem>&)), iv, SLOT(slotNewItem(QDropEvent*, const QValueList<QIconDragItem>&))); // Populate the QIconView with icons DDIconViewItem *item; item = new DDIconViewItem( iv, "Red", QPixmap( red_icon ) ); item->setRenameEnabled( TRUE ); item = new DDIconViewItem( iv, "Green", QPixmap( green_icon ) ); item->setRenameEnabled( TRUE ); item = new DDIconViewItem( iv, "Blue", QPixmap( blue_icon ) ); item->setRenameEnabled( TRUE ); return app.exec(); } See also Examples. Copyright © 2002 TrolltechTrademarks Qt version 3.0.5
