Hi, You should share the code of your MyWidgetTree class. That way it will make things easier to analyse.

Ok, now works perfectly, but I would ask if you can change the animation drag'n'drop between the lines. Currently, during the row drag it appears a copy of a line anchored to the mouse cursor. You can change this animation? #include <QWidget> #include <QTableWidget> #include <QDropEvent> #include <QDragMoveEvent> #include <QDropEvent> #include <QMimeData> #include <QDebug> #include <QKeyEvent> #ifndef DTABLEWIDGET_H #define DTABLEWIDGET_H class DTableWidget : public QTableWidget { Q_OBJECT public: DTableWidget(QWidget *parent = 0); public slots: signals: void keyboard(QKeyEvent *event); void dropped(const QMimeData* mimeData = 0); void moved(int old_row, int new_row); protected: void dragEnterEvent(QDragEnterEvent *event); void dragMoveEvent(QDragMoveEvent *event); void dragLeaveEvent(QDragLeaveEvent *event); void dropEvent(QDropEvent *event); void keyPressEvent(QKeyEvent* event); private: }; #endif #include <QtGui> #include "dtablewidget.h" #include "nofocusproxystyle.cpp" DTableWidget::DTableWidget(QWidget *parent) : QTableWidget(parent) { //set widget default properties: setFrameStyle(QFrame::Sunken | QFrame::StyledPanel); setDropIndicatorShown(true); setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn); setEditTriggers(QAbstractItemView::NoEditTriggers); setDragDropMode(QAbstractItemView::DropOnly); setAlternatingRowColors(true); setSelectionBehavior(QAbstractItemView::SelectRows); setShowGrid(false); setAcceptDrops(true); setWordWrap(false); setStyleSheet("selection-background-color: yellow;" "selection-color: #002041;" "font-size: 75%;" ); setStyle(new NoFocusProxyStyle()); } void DTableWidget::dragEnterEvent(QDragEnterEvent *event) { event->acceptProposedAction(); } void DTableWidget::dragMoveEvent(QDragMoveEvent *event) { event->acceptProposedAction(); } void DTableWidget::dropEvent(QDropEvent *event) { event->acceptProposedAction(); if (event->mimeData()->urls().size() > 0) emit dropped(event->mimeData()); else { QPoint old_coordinates = QPoint(-1,-1); int dropAction = event->dropAction(); if(currentItem() != NULL) //Check if user is not accessing empty cell { old_coordinates = QPoint(currentItem()->row(), currentItem()->column()); } QTableWidget::dropEvent(event); qDebug() << "Detected drop event..."; if(this->itemAt(event->pos().x(), event->pos().y()) != NULL && old_coordinates != QPoint(-1, -1)) { qDebug() << "Drop Event Accepted."; qDebug() << "Source: " << old_coordinates.x() << old_coordinates.y() << "Destinition: " << this->itemAt( event->pos().x(), event->pos().y() )->row() << this->itemAt( event->pos().x(), event->pos().y() )->column() << "Type: " << dropAction; emit moved(old_coordinates.x(), itemAt( event->pos().x(), event->pos().y())->row()); } } } void DTableWidget::dragLeaveEvent(QDragLeaveEvent *event) { event->accept(); } void DTableWidget::keyPressEvent(QKeyEvent *event) { emit keyboard(event); }

@Yohdu said: My second and main question is then : how to implement correct drag and drop operations with custom QStandardItem which needs to own custom data ? With the standard item widgets/models you can't drag-n-drop custom item roles. This makes sense, since the model doesn't know which UserRole+ was set. It would need to iterate all possible item-role values when creating the drop-data. The only solution i see is to create your own custom model and reimplement the needed drag-n-drop methods. This also give you full control over your data structure storing the data inside the model. This is more work, but you will learn a lot and gain some performance (by avoiding the standard-item classes)

Hi @Joel-Bodenmann , thank you, I got the point about the item delegate but I see two issues: implement a drag and drop listview because I ended up with empty lines (on the list view) and fields on the widget mapper: https://s32.postimg.org/47yyrq7id/Untitled.png implement a delegate that paint a checkbox with custom pixmap, the input with number and the input with text.

@Vagabond Heh. good work. Just as a note: you can use event filters to implement drag and drop on other widgets if no other need to subclass them. http://ynonperek.com/course/qt/event-filter2.html But for your case, subclassing QGroupBox is super.

Had a similar Issue. Was able to find a solution. Below is a generic PyQt5 example that solves the problem using right click. import sys from PyQt5.QtGui import * from PyQt5.QtWidgets import * from PyQt5.QtCore import * class Tabs(QTabWidget): def __init__(self, parent): super().__init__(parent) self.parent = parent self.setAcceptDrops(True) self.tabBar = self.tabBar() self.tabBar.setMouseTracking(True) self.indexTab = None self.setMovable(True) self.addTab(QWidget(self), 'Tab One') self.addTab(QWidget(self), 'Tab Two') def mouseMoveEvent(self, e): if e.buttons() != Qt.RightButton: return globalPos = self.mapToGlobal(e.pos()) tabBar = self.tabBar posInTab = tabBar.mapFromGlobal(globalPos) self.indexTab = tabBar.tabAt(e.pos()) tabRect = tabBar.tabRect(self.indexTab) pixmap = QPixmap(tabRect.size()) tabBar.render(pixmap,QPoint(),QRegion(tabRect)) mimeData = QMimeData() drag = QDrag(tabBar) drag.setMimeData(mimeData) drag.setPixmap(pixmap) cursor = QCursor(Qt.OpenHandCursor) drag.setHotSpot(e.pos() - posInTab) drag.setDragCursor(cursor.pixmap(),Qt.MoveAction) dropAction = drag.exec_(Qt.MoveAction) def dragEnterEvent(self, e): e.accept() if e.source().parentWidget() != self: return print(self.indexOf(self.widget(self.indexTab))) self.parent.TABINDEX = self.indexOf(self.widget(self.indexTab)) def dragLeaveEvent(self,e): e.accept() def dropEvent(self, e): print(self.parent.TABINDEX) if e.source().parentWidget() == self: return e.setDropAction(Qt.MoveAction) e.accept() counter = self.count() if counter == 0: self.addTab(e.source().parentWidget().widget(self.parent.TABINDEX),e.source().tabText(self.parent.TABINDEX)) else: self.insertTab(counter + 1 ,e.source().parentWidget().widget(self.parent.TABINDEX),e.source().tabText(self.parent.TABINDEX)) class Window(QWidget): def __init__(self): super().__init__() self.TABINDEX = 0 tabWidgetOne = Tabs(self) tabWidgetTwo = Tabs(self) layout = QHBoxLayout() self.moveWidget = None layout.addWidget(tabWidgetOne) layout.addWidget(tabWidgetTwo) self.setLayout(layout) if __name__ == '__main__': app = QApplication(sys.argv) window = Window() window.show() sys.exit(app.exec_())

@tokafr Super. so it can copy files on its own ? Doc hinted it, but I was not sure.

HI so rootItem is your "drop" widget? Is the yellow on picture rootitem or the white one where mouse is? ( A=8 ) It does look correct so a bit odd. and void dragEnterEvent(QDragEnterEvent* event) Q_DECL_OVERRIDE; should be called when u leave this small area. I assume you are 100% sure that is not called and its not just the change to while part that is failing. I can't guess from this little code what could be wrong.sorry. Just for test, could you run my editor and see it does indeed say "drag leave" when u drag from the list on the left to center. https://www.dropbox.com/s/ikra7pm161lzf56/DMDesigner.zip?dl=0

This issue is now resolved. It turned out to be a problem in the model: I forgot to tell the root (invalid parent) to accept drops too. This is done in the QAbstractItemModel::flags() implementation. The incorrect version was: Qt::ItemFlags MyModel::flags(const QModelIndex& index) const { if (!index.isValid()) { return 0; } return Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsDropEnabled; } While this is how it should look like to allow drops in the root (to add new items without a parent): Qt::ItemFlags MyModel::flags(const QModelIndex& index) const { if (!index.isValid()) { return Qt::ItemIsDropEnabled; // Allow drops in the top-level (no parent) } return Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsDropEnabled; }

Did you find the solution?

Hi @Joel-Bodenmann Have you got any solution/feedback for your question?

Well, I found solution. It is very simple, all I need is to set default drop action for my view class as Qt::MoveAction and return copy and move in the suporrtedDropActions().

@bsomervi Well, that's okay -- it's not that important that the indicator be there. Thanks for your help!

@raven-worx You're correct. I am now inserting a nullptr in the insertRows() function, and then later in setData I use the QList::replace() function to actually put a shape into that index. The reason it didn't work is that I used the pre-compiled Qt binaries. On the binaries, for some reason (probably that I don't know how to set it up properly), putting a breakpoint on any function that is defined in the source code does not trigger the debugger to stop there at all. I fixed that by deleting Qt, compiling it from the sources (with some headache), installing Qt Creator again and pointing it to the kit. Now I can put breakpoints into the source code and the debugger will actually stop on them, revealing that the call to setData actually does happen when dropping rows. After all this I came upon a solution that seems to work, I'd just like an opinion if this is a good way to go about it, it might need some polish. I figured I didn't want to reimplement the whole drag and drop system just to be able to pass some indexes through it, when I am already displaying the shape's names in the view, so I thought... to determine the index, I can just iterate through my list and find the shape that has the same name as the one that I clicked on. Here's what I do in setData: bool ShapeListModel::setData(const QModelIndex& index, const QVariant& value, int role) { //This role is used when double-clicking on an item if (index.isValid() && role == Qt::EditRole) { if (value.toString() != shapeList.at(index.row())->getName() && !value.toString().isEmpty()) { shapeList[index.row()]->setName(value.toString()); emit dataChanged(index, index); return true; } } //And this one when drag and dropping else if (role == Qt::DisplayRole) { Shape* shape {nullptr}; for (int i = 0; i < shapeList.size(); i++) { if (i == index.row()) { //do nothing } else { if (shapeList.at(i)->getName() == value.toString()) { shape = shapeList.at(i); if (shape) { shapeList.replace(index.row(), shape); return true; } } } } } return false; } So basically, I do a for loop on my shapeList to find the shape which has the name displayed in the QVariant "value" (the name that I clicked on in the view). Once I found it, I set a pointer to its address. Then I simply replace the contents of the empty row (the one with the nullptr) with the shape that I clicked on. Afterwards the call to removeRows takes care of the shape's original index. This works fine. The only requirement is that each shape has a unique name, which is probably a good idea to do anyways. The only thing I'm not sure about is the "else if (role == Qt::DisplayRole)", but according to the debugger that is the set role when drag and dropping. What do you think of this implementation?

I finally solved the issue in reimplementing the dropEvent like that : if (event) { // Get QTableWidget QTableWidget *table = qobject_cast<QtableWidget *>(event->source()); // Decode Mime Data QString format = QLatin1String("application/x-qabstractitemmodeldatalist"); QByteArray encoded = event->mimeData()->data(format); QDataStream stream(&encoded, QIODevice::ReadOnly); // Decode format (row, column) to get row & column coordinates int row,column; stream >> row >> column; }

Yes, of course... Sorry, it was a long day and I didn't pay enough attention. I now managed to implement a working version. I don't yet render the QGraphicsItem into a QPixmap but for the first version I am pretty happy with the fact that it just doesn't render the standard selection box thingy. My code: void WidgetsLibraryView::startDrag(Qt::DropActions supportedActions) { // Partly copied from Qt 5.5.5 sources QModelIndexList indexes = selectedIndexes(); if (indexes.count() > 0) { // Get a list of the supported MIMEs of the selected indexes QMimeData* data = model()->mimeData(indexes); if (!data) { return; } // Create the drag object QDrag* drag = new QDrag(this); drag->setMimeData(data); // Execute the drag drag->exec(supportedActions, Qt::CopyAction); } } Thank you for your help! Very appreciated.

The logic is the same, you have to handle the mime type used by Window's explorer when you drag the file on the widget.