Drag and drop item text from QTreeView to QLineEdit

Question

I need to drop an item from a QTreeView with a QStandardItemModel into a QLineEdit.

I'm a little lost at how to get the data from the QTreeView. Assuming this has something to do with re-implementing the dropMimeData method but dealing with mimeData is not something I do that often (or fully understand for that matter).

Here's a skeletal bit of example code, I need to drag the items in MyTreeView into MyLineEdit and have it set the text to whatever the item text is.

from PySide.QtCore import *
from PySide.QtGui import *

class MyWidget(QWidget):
    def __init__(self):
        super(MyWidget, self).__init__()

        model = MyModel()
        view = MyTreeView()
        view.setModel(model)
        lineEdit = MyLineEdit()

        model.addItem('My Item')
        model.addItem('My Item2')


        layout = QVBoxLayout()
        layout.addWidget(view)
        layout.addWidget(lineEdit)

        self.setLayout(layout)

class MyLineEdit(QLineEdit):
    def __init__(self):
        super(MyLineEdit, self).__init__()
        self.setAcceptDrops( True )

    def dragEnterEvent(self, event):
        data_type = "application/x-qstandarditemmodeldatalist"
        if event.mimeData().hasFormat(data_type):
            event.accept()
        else:
            event.ignore()

    def dropEvent(self, event):
        data_type = "application/x-qstandarditemmodeldatalist"
        if event.mimeData().hasFormat(data_type):
            #Get the QStandardItem text somehow?
            item_text = 'Get the text somehow'
            self.setText(item_text)


class MyModel(QStandardItemModel):
    def __init__(self):
        super(MyModel, self).__init__()

    def addItem(self, text):        
        root_item = self.invisibleRootItem()
        item = QStandardItem(text)
        root_item.appendRow(item)

class MyTreeView(QTreeView):
    def __init__(self):
        super(MyTreeView, self).__init__()
        self.setDragEnabled( True )

widget = MyWidget()
widget.show()

Answer 1

This can be achieved very simply by reimplementing mimeData in your model:

class MyModel(QStandardItemModel):
    ...
    def mimeData(self, indexes):
        mimedata = super(MyModel, self).mimeData(indexes)
        if indexes:
            mimedata.setText(indexes[0].data())
        return mimedata

That's all that's needed. You don't need to implement dragEnterEvent or dropEvent in the line-edit.

Answer 2

There are several alternatives to obtain the text:

• Using the mimeData()

---

def dropEvent(self, event):
    data_type = "application/x-qstandarditemmodeldatalist"
    mimeData = event.mimeData()
    if mimeData.hasFormat(data_type):
        encodedData = mimeData.data(data_type)
        stream = QDataStream(encodedData, QIODevice.ReadOnly)
        row = stream.readInt32()
        column = stream.readInt32()
        it = QStandardItem()
        stream >> it
        self.setText(it.text())

---

• Using source() which is the widget where the drag operation is performed, in this case it is the view, then we access the current QModelIndex which is the selected one.

---

def dropEvent(self, event):
    if isinstance(event.source(), QAbstractItemView):
        ix = event.source().currentIndex()
        self.setText(ix.data())

---

If you enable the selection of several items then you must use the selected items:

...

class MyLineEdit(QLineEdit):
    def __init__(self):
        super(MyLineEdit, self).__init__()
        self.setAcceptDrops( True )

    def dragEnterEvent(self, event):
        data_type = "application/x-qstandarditemmodeldatalist"
        if event.mimeData().hasFormat(data_type):
            event.accept()
        else:
            event.ignore()

    def dropEvent(self, event):
        if isinstance(event.source(), QAbstractItemView):
            ixdexes = event.source().selectedIndexes()
            text = " ".join([ix.data() for ix in sorted(ixdexes)])
            self.setText(text)


...

class MyTreeView(QTreeView):
    def __init__(self):
        super(MyTreeView, self).__init__()
        self.setDragEnabled( True )
        self.setSelectionMode(QAbstractItemView.MultiSelection)

...