Custom dropEvent in TreeWidget: how to find target item (tree item under mouse?)

Alabaster

PyQt4 / Python 3

I'm dragging text from a listwidget to a treewidget, but I need to override the default drag-and-drop behavior because I'm using a custom TreeWidgetItem class. I cannot figure out how to find the tree item currently under the mouse during a dropEvent. Any help would be much appreciaed!

A simple sample code is below:

@
import sys
from PyQt4.QtGui import *
from PyQt4.QtGui import *

class EditScreen(QWidget):
def init(self):
super(EditScreen, self).init()
self.initUI()

def initUI(self):
    global tree
    global listbox
    self.vbox = QVBoxLayout()
    self.hbox = QHBoxLayout()
    
    
    listbox = QListWidget()
    listbox.setDragEnabled(True)
    listbox.setSelectionMode(QAbstractItemView.ExtendedSelection) 
    for x in range(1,10):
        item = 'Thing' + str(x)
        listbox.addItem(item)
        
    tree = MyTreeWidget()
    tree.setAcceptDrops(True)
    tree.setSelectionMode(QAbstractItemView.ExtendedSelection) 
    for x in range(1,5):
        addnewtreeitem = MyTreeItemClass('Category ' + str(x), toplevel=True)
        addnewtreeitem.setExpanded(True)
    
    question = 'Double-clicking a category in the treewidget (right) calls my "addHere" function,'
    question += '\nwhich adds the selected items (from the left) to the treeview after messing with them a bit.'
    question += '\n\nI would like to drag items over from the listwidget, with exactly the same functionality as the double-click.'
    question += '\nbut I do not understand how to find the target item (underneath the mouse) during a dropEvent.'
    question += '\nI need this target item in order to call my "addHere" function.'
    question += '\n\nI cannot use the standard drag-and-drop behavior because I must use a custom TreeWidgetItem class.'
    
    
    questionlabel = QLabel(question)
    self.hbox.addWidget(listbox)
    self.hbox.addWidget(tree)
    
    
    self.vbox.addWidget(questionlabel)
    
    self.vbox.addLayout(self.hbox)
    
    self.setLayout(self.vbox)
    self.setWindowTitle('How can I make drag-and-drop perform my "addHere" function?')
    self.show()
    
def keyPressEvent(self, e):        
    if e.key() == Qt.Key_Delete:
        #print('pressed delete key')
        tree.delButtonPressed()

class MyTreeWidget(QTreeWidget):
def init(self):
QTreeWidget.init(self)
self.itemDoubleClicked.connect(self.addHere)

def delButtonPressed(self):
    for item in self.selectedItems():
        if item.deletable:
            item.parent.removeChild(item)
            MyTreeItemClass.child_list.remove(item)
    
def addHere(self, clickeditem, column):
    global listbox
    
    for x in listbox.selectedItems():
        if clickeditem.can_add_here == True:
            print('Adding item(s) here', clickeditem.treetext)
            itemtext = x.text()
            newtreeitem = MyTreeItemClass(itemtext, parent=clickeditem)
            clickeditem.setExpanded(False)  # need to use false to counter-act the double-clicking action?
        else:
           print('cannot add to this item')

class MyTreeItemClass(QTreeWidgetItem):
global tree
toplevel_list = []
child_list = []
def init(self, treetext, toplevel=False, parent=None):
self.treetext = treetext
QTreeWidgetItem.init(self, [self.treetext])

    if parent:
        self.parentitem=parent
    
    if toplevel == True:
        self.deletable = False
        self.can_add_here = True
        MyTreeItemClass.toplevel_list.append(self)
        tree.addTopLevelItem(self)
        
    else:
        self.deletable = True
        self.can_add_here = False
        itemnum = int(self.treetext[-1])
        
        if itemnum % 2 == 0:
            self.setForeground(0,QBrush(Qt.blue))
        else:
            self.setForeground(0,QBrush(Qt.red))

        if itemnum % 3 == 0:
            self.setBackground(0,QBrush(Qt.lightGray))

        if itemnum % 4 == 0:
            self.setBackground(0,QBrush(Qt.black))
            self.setForeground(0,QBrush(Qt.white))

        MyTreeItemClass.child_list.append(self)
        self.parentitem.addChild(self)

def main():
app = QApplication(sys.argv)
editscreen = EditScreen()
sys.exit(app.exec_())

main()
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jazzycamel

"QTreeWidget.itemAt":http://doc.qt.digia.com/qt/qtreewidget.html#itemAt is what your looking for. Try adding the following to your MyTreeWidget class:

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def dropEvent(self, e):
item=self.itemAt(e.pos())
if item: self.addHere(item)
e.accept()
@

You might also want to do the following in the constructor to stop the default expand behavior:

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self.setExpandsOnDoubleClick(False)
@

Hope this helps ;o)

Alabaster

This worked great! Thanks so much.