Qt-interest Archive, November 2007
Custom mimeData in drag and drop using model/view classes
Message 1 in thread
Hi all.
I've got a problem for which I need clarification. I've got two models
displayed by a ListView and a TableView, respectively, and I'd like to
drag elements from the listview into cell's in the tableview. Here's
some abbreviated code of what I've got so far:
//FileItem
class FileItem; //A regular non-qt class
class FileModel : public QAbstractListModel {...};
// The flags method for the FileModel:
Qt::ItemFlags FileModel::flags(const QModelIndex &index) const {
if (!index.isValid())
return Qt::ItemIsEnabled;
return QAbstractListModel::flags(index) | Qt::ItemIsDragEnabled;
}
//The table
class MyTableItem; //Also a regular non-qt class
class MyTableModel : public QAbstractTableModel{...};
The setup of the views:
//Setup FileList
QListView *listView = QListView(this)
listModel *fileModel = new FileModel();
listView->setModel(fileModel);
listView->setSelectionMode(QAbstractItemView::SingleSelection);
listView->setDragEnabled(true);
//Setup tableView
QTableView *tableView = new QTableView(this);
MyTableModel *tableModel = new MyTableModel();
tableView->setModel(m);
tableView->setSelectionMode(QAbstractItemView::SingleSelection);
tableView->setDragEnabled(true);
tableView->setAcceptDrops(true);
tableView->setDropIndicatorShown(true);
With this code it's possible to drag and drop items from the listView to
the tableView. A mimeData object, with format
"application/x-qabstractitemmodeldatalist", is even recieved in
MyTableModel::dropMimeData(...);
So far, so good. Now I'd like to add some custom data to the mimeData,
so I extend the model for the listView with
QStringList FileModel::mimeTypes() const{
QStringList types;
types<<"application/x-myowncustomdata";
return types;
}
and
QMimeData *FileModel::mimeData(const QModelIndexList &indexes) const{
QByteArray encodedData;
... encode the data ...
mimeData->setData("application/x-myowncustomdata", encodedData);
return mimeData;
}
but now the tableView will not accept the dragged/dropped items. (The
mouse-pointer turns into a crossed out circle.) It does not matter what
mimeType I use, it even fails on "text/plain" data.
Have I missed a crucial point in the documentation or to set some
required properties in the views, mimeData or some place else?
The code has been tested on Fedora7 using qt4.3.2-1.x86_64 and windows
XP using Qt4.1.2.
/Allan
--
[ signature omitted ]
Message 2 in thread
Can you post your dragEnterEvent and dropEvent methods for your table
view? My initial guess would be that you aren't accepting the mime data
format you created ("application/x-myowncustomdata").
chris burke
phone: 617-621-0060 x195
email: cburke@xxxxxxx
skype: chris.burke0
Allan Rasmusson wrote:
> Hi all.
> I've got a problem for which I need clarification. I've got two
> models displayed by a ListView and a TableView, respectively, and I'd
> like to drag elements from the listview into cell's in the tableview.
> Here's some abbreviated code of what I've got so far:
>
> //FileItem
> class FileItem; //A regular non-qt class
>
> class FileModel : public QAbstractListModel {...};
>
> // The flags method for the FileModel:
> Qt::ItemFlags FileModel::flags(const QModelIndex &index) const {
> if (!index.isValid())
> return Qt::ItemIsEnabled;
> return QAbstractListModel::flags(index) | Qt::ItemIsDragEnabled;
> }
>
> //The table
> class MyTableItem; //Also a regular non-qt class
>
> class MyTableModel : public QAbstractTableModel{...};
>
>
> The setup of the views:
>
> //Setup FileList
> QListView *listView = QListView(this)
> listModel *fileModel = new FileModel();
> listView->setModel(fileModel);
> listView->setSelectionMode(QAbstractItemView::SingleSelection);
> listView->setDragEnabled(true);
>
> //Setup tableView
> QTableView *tableView = new QTableView(this);
> MyTableModel *tableModel = new MyTableModel();
> tableView->setModel(m);
> tableView->setSelectionMode(QAbstractItemView::SingleSelection);
> tableView->setDragEnabled(true);
> tableView->setAcceptDrops(true);
> tableView->setDropIndicatorShown(true);
>
> With this code it's possible to drag and drop items from the listView
> to the tableView. A mimeData object, with format
> "application/x-qabstractitemmodeldatalist", is even recieved in
>
> MyTableModel::dropMimeData(...);
>
> So far, so good. Now I'd like to add some custom data to the mimeData,
> so I extend the model for the listView with
>
> QStringList FileModel::mimeTypes() const{
> QStringList types;
> types<<"application/x-myowncustomdata";
> return types;
> }
>
> and
>
> QMimeData *FileModel::mimeData(const QModelIndexList &indexes) const{
> QByteArray encodedData;
> ... encode the data ...
> mimeData->setData("application/x-myowncustomdata", encodedData);
> return mimeData;
> }
>
> but now the tableView will not accept the dragged/dropped items. (The
> mouse-pointer turns into a crossed out circle.) It does not matter
> what mimeType I use, it even fails on "text/plain" data.
>
> Have I missed a crucial point in the documentation or to set some
> required properties in the views, mimeData or some place else?
>
> The code has been tested on Fedora7 using qt4.3.2-1.x86_64 and windows
> XP using Qt4.1.2.
>
> /Allan
>
> --
> To unsubscribe - send a mail to qt-interest-request@xxxxxxxxxxxxx with
> "unsubscribe" in the subject or the body.
> List archive and information: http://lists.trolltech.com/qt-interest/
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Message 3 in thread
Chris Burke wrote:
> Can you post your dragEnterEvent and dropEvent methods for your table
> view? My initial guess would be that you aren't accepting the mime
> data format you created ("application/x-myowncustomdata").
>
> chris burke
> phone: 617-621-0060 x195
> email: cburke@xxxxxxx
> skype: chris.burke0
>
>
Ah... it makes sense now. What I've been using is the QTableView itself;
I haven't specialized it. The reason was that the functionality of the
QTableView is exactly what I want, just with a custom mimetype for drag
and drop. I figured QTableView accepts ANY mime-type and that people
limit this through specialization. Apparently it works the other way around.
Since my initial post I've specialized the QTableView in order to make
the dragEnterEvent, dropEvent and also the dragMoveEvent accept the
mimeType explicitly. Now it's working besides I seem to have to
implement the indication of drop position identical to one in QTableView.
/Allan
--
[ signature omitted ]
Message 4 in thread
On torsdag den 1. November 2007, Allan Rasmusson wrote:
> Hi all.
> I've got a problem for which I need clarification. I've got two models
> displayed by a ListView and a TableView, respectively, and I'd like to
> drag elements from the listview into cell's in the tableview.
Another way to solve this is to add your custom data to be something you can
put inside a QVariant, and implement operator << and >> for QDataStream, and
then I think you should be able to use the existing drag and drop code.
I don't know if this trick really works, but I can't see why it shouldn't. You
might need to do a bit more research to figure out how the drag encoding and
decoding of the variants in the views before it works.
Bo.
> Here's
> some abbreviated code of what I've got so far:
>
> //FileItem
> class FileItem; //A regular non-qt class
>
> class FileModel : public QAbstractListModel {...};
>
> // The flags method for the FileModel:
> Qt::ItemFlags FileModel::flags(const QModelIndex &index) const {
> if (!index.isValid())
> return Qt::ItemIsEnabled;
> return QAbstractListModel::flags(index) | Qt::ItemIsDragEnabled;
> }
>
> //The table
> class MyTableItem; //Also a regular non-qt class
>
> class MyTableModel : public QAbstractTableModel{...};
>
>
> The setup of the views:
>
> //Setup FileList
> QListView *listView = QListView(this)
> listModel *fileModel = new FileModel();
> listView->setModel(fileModel);
> listView->setSelectionMode(QAbstractItemView::SingleSelection);
> listView->setDragEnabled(true);
>
> //Setup tableView
> QTableView *tableView = new QTableView(this);
> MyTableModel *tableModel = new MyTableModel();
> tableView->setModel(m);
> tableView->setSelectionMode(QAbstractItemView::SingleSelection);
> tableView->setDragEnabled(true);
> tableView->setAcceptDrops(true);
> tableView->setDropIndicatorShown(true);
>
> With this code it's possible to drag and drop items from the listView to
> the tableView. A mimeData object, with format
> "application/x-qabstractitemmodeldatalist", is even recieved in
>
> MyTableModel::dropMimeData(...);
>
> So far, so good. Now I'd like to add some custom data to the mimeData,
> so I extend the model for the listView with
>
> QStringList FileModel::mimeTypes() const{
> QStringList types;
> types<<"application/x-myowncustomdata";
> return types;
> }
>
> and
>
> QMimeData *FileModel::mimeData(const QModelIndexList &indexes) const{
> QByteArray encodedData;
> ... encode the data ...
> mimeData->setData("application/x-myowncustomdata", encodedData);
> return mimeData;
> }
>
> but now the tableView will not accept the dragged/dropped items. (The
> mouse-pointer turns into a crossed out circle.) It does not matter what
> mimeType I use, it even fails on "text/plain" data.
>
> Have I missed a crucial point in the documentation or to set some
> required properties in the views, mimeData or some place else?
>
> The code has been tested on Fedora7 using qt4.3.2-1.x86_64 and windows
> XP using Qt4.1.2.
>
> /Allan
>
> --
> To unsubscribe - send a mail to qt-interest-request@xxxxxxxxxxxxx with
> "unsubscribe" in the subject or the body. List archive and information:
> http://lists.trolltech.com/qt-interest/
--
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