[SOLVED]How to delete an item from the treeview by droping an item to pushbutton or to an group box

[Ratzz]

@mrjj
Yes, i Tried you code which turns out to be a Dropbutton. How to implement it in my code ?

[mrjj]

@Ratzz
As I wrote in answer ?
Using the promote feature.
Which will runtime replace a normal button with the DropButton.
Or you can new a button you self
Like
Dropbutton *but=Dropbutton (this)
and insert into your window/layout.

[Ratzz]

@mrjj
Yes its working now fine..
I have group box adjacent to treeview. Can i implement the same to groupbox?

[mrjj]

@Ratzz
Super.
Well If you promote the GroupBox, there might be issue with
Parent. I have never tried it.
Try it :)
If it says funny stuff , just demote it to a groupbox again.

Else its pretty much the same, except new filename and new name.

#include <QGroupBox>
#include <QDragMoveEvent>

class DropGroupBox : public QGroupBox {
  Q_OBJECT
 public:
  explicit  DropGroupBox(QWidget* parent = 0) : QGroupBox(parent) {
    setAcceptDrops(true);
  }
 protected:
  void dragEnterEvent(QDragEnterEvent* event) {
    event->acceptProposedAction();
  }

  void dropEvent(QDropEvent* event) {
    event->setDropAction(Qt::MoveAction);
    event->accept();
  }
};

[Ratzz]

@mrjj
i promoted the group using Qpushbutton but not allow me to promote the GroupBox. so i added dropgroupBox.h and promoted it.
But its not working.

[mrjj]

@Ratzz
Hi
Something must gone wrong. maybe.
Tried it here and it does accept drops

https://www.dropbox.com/s/7bkqatzm6vt1kmz/promotedgb.zip?dl=0

[SGaist]

Out of curiosity… Why are you creating so many widgets that should allow to delete items from your view using dnd ? It doesn't feel very intuitive nor following the guidelines of major OSs

[Ratzz]

@mrjj
Yes your code is working . But do not know in my case its not working .
You have used Listwidget and i have used list view . Does it matters??

[Ratzz]

@SGaist
Yes , My treeview is in between listview and groupbox . even if the listview items are dragged to the pushbutton_delete its getting deleted. which in my case should not. what is the best way to do ??

[SGaist]

Implement it in one of the usual ways:

• React to the delete or backspace key
• Have a delete button that will delete the currently selected row/column etc.
• Have a dedicated column with e.g. a QPushButton to delete the row completely.

[Ratzz]

@SGaist
I already have a delete button which deletes entire row.

[Ratzz]

@mrjj
The code you shared is working (group box).

[mrjj]

@Ratzz
Ok. super.

[Ratzz]

@mrjj
But now i can drag items from treeview as well as listview to pushbutton and groupbox. But i do not want the user to allow listview items to dragged to pushbutton/groupbox

[mrjj]

@Ratzz
Hmm maybe you can check with
sender();
in dragEnterEvent
and if its the not a Treeview then reject the drop

like

QTreeView* theone= dynamic_cast<QTreeView*>(sender());
   if( theone!= NULL ) 
   { 
      event->acceptProposedAction();
   }

[Ratzz]

@mrjj
I do not have dragEnterEvent event yet! . we have a custom event using dropMimeData .

[mrjj]

@Ratzz
how does this custom event look like ?

and its not an options just to disable Drag from listview?

[Ratzz]

@mrjj
All drag drop events are handled in this. I am not aware how Bec, previous programmer has done it.

bool MessageModel::dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent)
{
    if(action == Qt::CopyAction)
    {
//        QStringList format = data->formats();
        QByteArray encodedData = data->data("application/x-qabstractitemmodeldatalist");
        QDataStream stream(&encodedData, QIODevice::ReadOnly);
        QMap<int,  QVariant> roleDataMap;
//        roleDataMap.setInsertInOrder(true);
        QMap<int, QString> sortMsgs;

        while (!stream.atEnd())
        {
            int row, col;
            stream >> row >> col >> roleDataMap;
            QString tmp = roleDataMap.value(0).toString();
            //MsgId1.append(tmp);
            sortMsgs.insert(row,tmp);
        }
        QList < QString > MsgId1 = sortMsgs.values();

        if(parent.parent().isValid() && !parent.parent().parent().isValid())
        {
            QStandardItemModel::dropMimeData(data,action,row,column,parent);
            emit addFrameMessageIds(parent.row(), -1, MsgId1);
            return true;
        }
        if(parent.parent().parent().isValid() && column == -1)
        {
            QStandardItemModel::dropMimeData(data,action,parent.row() +1,column,parent.parent());
            emit addFrameMessageIds(parent.parent().row(),parent.row() +1, MsgId1);
            return true;
        }
        if(parent.parent().parent().isValid() && column == 0)
        {
            QStandardItemModel::dropMimeData(data,action,row,column,parent);
            emit addFrameMessageIds(parent.row(), row, MsgId1);
            return true;
        }
    }
    else if(action == Qt::MoveAction)
    {
        if(!parent.isValid())
        {
            return QStandardItemModel::dropMimeData(data,action,indexesLocal.row(),indexesLocal.column(),indexesLocal.parent());
        }
        if(indexesLocal.parent().parent().isValid() && !parent.parent().isValid() && column == -1)
        {
            //Msg is dropped on major frame
            return QStandardItemModel::dropMimeData(data,action,indexesLocal.row(),indexesLocal.column(),indexesLocal.parent());
        }
        if(indexesLocal.parent().parent().isValid() && !parent.parent().parent().isValid() && column == -1)
        {
            //Msg is dropped on minor frame
            if(indexesLocal.parent().row() != parent.row())
            {
                QStandardItemModel::dropMimeData(data,action,row,column,parent);
                emit moveFrameMessageIds(indexesLocal.parent().row(),parent.row(),indexesLocal.row(),-1);
                return true;
            }
            else
            {
                QStandardItemModel::dropMimeData(data,action, 0 ,column,parent);
                emit moveFrameMessageIds(indexesLocal.parent().row(),parent.row(),indexesLocal.row(),0);
                return true;
            }
        }
        if(indexesLocal.parent().parent().isValid() && parent.parent().parent().isValid() && column == -1)
        {
            //      Msg is dropped on another msg
            QStandardItemModel::dropMimeData(data,action,parent.row()+1,column,parent.parent());
            emit moveFrameMessageIds(indexesLocal.parent().row(),parent.parent().row(),indexesLocal.row(),parent.row()+1);
            return true;
        }
        if(indexesLocal.parent().isValid() && !(indexesLocal.parent().parent().isValid()) && !parent.parent().isValid() && column == -1)
        {
            //      Minor frame is dropped on Major frame
            QStandardItemModel::dropMimeData(data,action,0,indexesLocal.column(),indexesLocal.parent());
            emit moveFrame(indexesLocal.row(),0);
            return true;
        }
        if(indexesLocal.parent().isValid() && !(indexesLocal.parent().parent().isValid()) && parent.parent().isValid() && !(parent.parent().parent().isValid()) && column == -1)
        {
            // Minor frame is dropped on another minor frame
            int pre = indexesLocal.row();
            int cur = parent.row();
            QStandardItemModel::dropMimeData(data,action,parent.row()+1,column,parent.parent());
            emit moveFrame(indexesLocal.row(),parent.row());
            return true;
        }
        if(indexesLocal.parent().isValid() && !(indexesLocal.parent().parent().isValid()) && parent.parent().parent().isValid() && column == -1)
        {
            return QStandardItemModel::dropMimeData(data,action,indexesLocal.row(),indexesLocal.column(),indexesLocal.parent());
            //      Minor frame is dropped on msg
        }
        if(indexesLocal.parent().isValid() && !(indexesLocal.parent().parent().isValid()) && !parent.parent().isValid() && column == 0)
        {
            QStandardItemModel::dropMimeData(data,action,row,indexesLocal.column(),indexesLocal.parent());
            emit moveFrame(indexesLocal.row(),row);
            return true;
            //      Minor frame is dropped after minor
        }
        if(indexesLocal.parent().isValid() && !(indexesLocal.parent().parent().isValid()) && !parent.parent().parent().isValid() && column == 0)
        {
            return QStandardItemModel::dropMimeData(data,action,indexesLocal.row(),indexesLocal.column(),indexesLocal.parent());
            //      Minor frame is dropped after msg
        }
        if(indexesLocal.parent().parent().isValid() && parent.isValid() && !parent.parent().isValid() && column == 0)
        {
            return QStandardItemModel::dropMimeData(data,action,indexesLocal.row(),indexesLocal.column(),indexesLocal.parent());
            //      Msg is dropped after minor
        }
        if(indexesLocal.parent().parent().isValid() && parent.parent().isValid() && !parent.parent().parent().isValid() && column == 0)
        {
            QStandardItemModel::dropMimeData(data,action,row,parent.column(),parent);
            emit moveFrameMessageIds(indexesLocal.parent().row(),parent.row(),indexesLocal.row(),row);
            return true;
            //      Msg is dropped after msg
        }
}
}

And one more thing. If i drag items to pushbutton/group box the listview count is not getting updated.. ex:if i have 5 items and drag 1 item to pushbutton_delete then the count will be 5 . if i manually press delete button now then the list is getting updated to 3.

[mrjj]

@Ratzz said:

But i do not want the user to allow listview items to dragged to pushbutton/groupbox

So why can you not check there ?

also
http://doc.qt.io/qt-5/qtreewidget.html#dropMimeData
Seems to be when something is dropped on Tree and im confused what it has to do with the
Groupbox ?

[Ratzz]

@mrjj
Since the groupbox is deletes item as you suggested it also deletes listview items when dragged.