PyQt get sender/source of DragLeaveEvent

Question

hi got this bit of code in PyQt5 (PyQt: v 5.15.7) , basically I am trying to track widget that are dragged outside QMainwindow :

#!/usr/bin/env python3

from PyQt5.QtWidgets import (QApplication, QWidget, QMainWindow, 
                             
                             QVBoxLayout, QPushButton, QGridLayout
                             )
                            
from PyQt5.QtCore import Qt, QMimeData, pyqtSignal, pyqtSlot
from PyQt5.QtGui import QDrag, QPixmap, QCursor

class DragWidget(QWidget):
    
    def __init__(self, *args, name , **kwargs):
        super().__init__(*args, **kwargs)
    
    def mouseMoveEvent(self, e):

        if e.buttons() == Qt.LeftButton:
            drag = QDrag(self)
            mime = QMimeData()
            drag.setMimeData(mime)

            pixmap = QPixmap(self.size())
            self.render(pixmap)
            drag.setPixmap(pixmap)

            drag.exec_(Qt.MoveAction)

class MainWindow(QMainWindow):
    
    
    whereDropped = pyqtSignal(int,int)
    
    dragleaves = pyqtSignal()
    

    def __init__(self):
        super().__init__()
        
        self.setGeometry(200,200, 400, 500)
        
        
        
        self.container = QWidget()
        
        self.layout = QGridLayout()

        self.container.setLayout(self.layout)

        self.setCentralWidget(self.container)
        
        for i in range(4):
            
            self.x = DragWidget(self, name = 'widget_'+str(i))
            
            self.layout.addWidget( self.x)
            
            self.x.setObjectName('widget_'+str(i))
            
            self.b = QPushButton('widget___'+str(i))
            
            
                                    
            
            self.layout_2 = QVBoxLayout()
            
            self.x.setLayout(self.layout_2)
            
            self.layout_2.addWidget(self.b)
            
            
            
            self.x.show()

    
        
        self.installEventFilter(self)
        
        self.setAcceptDrops(True)
        
        self.whereDropped.connect(self.attdeta)
        
        self.dragleaves.connect(self.removeParent)
    
    @pyqtSlot()
    def removeParent(self) :
        
        print("\n\nself.dragleaves.connect(self.removeParent))")
        pass
        
    
    @pyqtSlot(int, int)    
    def attdeta(self, tupx, tupy) :
        
        print("\n\nself.whereDropped.connect(self.attdeta)")
        print('tupxy : ', tupx , tupy)
    
    
    
    def dropEvent(self, e):
        pos = e.pos()
        widget = e.source()
        
        print('\n\ndropEvent _________')
        print('widget = e.source() :' , widget)
        
        print('e.pos()  : ' , pos ,'\n\n')

        
        self.whereDropped.emit(e.pos().x(), e.pos().y())

        e.accept()
    
    def dragEnterEvent(self, e):
        
        print('dragEnterEvent _________' , e.source(), '\n')
        print('dragEnterEvent _________event-source-name :'  ,e.source().objectName())
        
        print('e.pos()  : ' , e.pos().x())
        
        print('e.pos()  : ' , e.pos().y() ,'\n\n')
        
        e.accept()
        
    def dragLeaveEvent(self, event):
        
        print('\n\nDragLeaveEvent event : ', event)
        
        # print(event.sender())  ### AttributeError: 'QDragLeaveEvent' object has no attribute 'sender'
      
        # print(event.source()) ### AttributeError: 'QDragLeaveEvent' object has no attribute 'source'

        print("Drag left at: " + str(self.mapFromGlobal(QCursor.pos())))     
        
        
        print('self.dragleaves.emit()')
        self.whereDropped.emit(self.mapFromGlobal(QCursor.pos()).x(), self.mapFromGlobal(QCursor.pos()).y()) ## see [https://stackoverflow.com/questions/50022465/how-do-i-get-the-exit-point-from-a-qdragleaveevent][1]
        
        self.dragleaves.emit()
        
        event.accept()


app = QApplication([])
w = MainWindow()
w.show()

app.exec_()

Any chance of getting sender/sorce/widget of dragLeaveEvent like for

dragEnterEvent ??? :

def dragEnterEvent(self, e):
        
        print('dragEnterEvent _________' , e.source(), '\n')
        print('dragEnterEvent _________event-source-name :'  ,e.source().objectName())
        
        print('e.pos()  : ' , e.pos().x())
        
        print('e.pos()  : ' , e.pos().y() ,'\n\n')
        
        e.accept()

Answer 1

Since a QDragLeaveEvent is always preceded by a QDragEnterEvent, you can store the source widget at the dragEnterEvent() and use it at the dragLeaveEvent().

So, do like this.

...
    def dragEnterEvent(self, e):
        self.drag_source = e.source()
        ...
        
    def dragLeaveEvent(self, event):
        print('dragLeaveEvent, drag_source:', self.drag_source)
        ...
...