title: QListWidget: How to drag and drop insert custom widget w/ icon?
body: <p>I've created a custom QListWidget with custom list widgets (just QPushButton widgets, for this example) added to it's QListWidgetItems, all setup so that I can drag and drop from a QPushButton, to add another button to the QListWidget.  In the first list widget, you'll notice that you get a dotted line inbetween two list widget items, indicating that you can drag and insert a widget between two existing ones.  However, with my custom list, I've lost that behavior.  I can still drop them between existing widgets, but there's no visual indicator to the user as before, of a horizontal bar between the two widgets where it will be inserted.  Does anyone know how I would do that?  You can see in the image below, the line in the first list that is the default indicator for inserting an item between two.  The red arrow points to that kind of custom insertion indicator that I'd like to create.</p>
  
  <p><a href="https://i.stack.imgur.com/0DgoV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0DgoV.png" alt="insertIndicator"></a></p>
  
  <p>And secondly, when I drag and drop from my custom QPushButton, it is highlighted black, but never returns to its normal grey color again, as shown in the image above.  How would I get this button back to its default state?</p>
  
  <pre><code>from inspect import isclass
  from shiboken2 import wrapInstance
  from PySide2 import QtCore, QtGui, QtWidgets
  from maya import OpenMayaUI as omui
  
  
  def show_ui():
      main_win_obj = omui.MQtUtil.mainWindow()
      main_win = wrapInstance(long(main_win_obj), QtWidgets.QWidget)
      win = Test(parent=main_win)
      win.show()
  
  
  class DragButton(QtWidgets.QPushButton):
  
      def __init__(self, parent=None, text=''):
          super(DragButton, self).__init__()
          self.setText(text)
  
      def mouseMoveEvent(self, event):
  
          if event.buttons() != QtCore.Qt.LeftButton:
              super(DragButton, self).mouseMoveEvent(event)
              return
  
          btn_img = self.grab()
          painter = QtGui.QPainter(btn_img)
          painter.setCompositionMode(
              painter.CompositionMode_DestinationIn
          )
          painter.fillRect(btn_img.rect(), QtGui.QColor(0, 0, 0, 127))
          painter.end()
  
          data = QtCore.QMimeData()
          data.setText('ReorderListAdd()')
  
          drag = QtGui.QDrag(self)
          drag.setMimeData(data)
          drag.setPixmap(btn_img)
          drag.setHotSpot(event.pos())
          drag.exec_(QtCore.Qt.CopyAction)
  
          super(DragButton, self).mouseMoveEvent(event)
  
      def mouseReleaseEvent(self, event):
  
          data = QtCore.QMimeData()
          data.setText('my text')
  
          drag = QtGui.QDrag(self)
          drag.setMimeData(data)
          drag.exec_()
  
          super(DragButton, self).mouseReleaseEvent(event)
  
  
  class ReorderList(QtWidgets.QListWidget):
  
      def __init__(self, parent=None):
          super(ReorderList, self).__init__(parent)
  
          self.setDragDropMode(
              QtWidgets.QAbstractItemView.InternalMove
          )
          self.setAcceptDrops(True)
          self.setAlternatingRowColors(True)
          self.setSelectionMode(
              QtWidgets.QAbstractItemView.SingleSelection
          )
          self.setDragDropMode(
              QtWidgets.QAbstractItemView.InternalMove
          )
  
      def add_btn(self, text='', index=-1):
  
          widget = QtWidgets.QWidget()
          if not text:
              text = 'item {0}'.format(self.count() + 1)
          btn = QtWidgets.QPushButton(text)
  
          layout = QtWidgets.QVBoxLayout(widget)
          layout.setContentsMargins(2, 2, 2, 2)
          layout.setSpacing(2)
          layout.addWidget(btn)
  
          item = QtWidgets.QListWidgetItem()
          item.setSizeHint(widget.sizeHint())
  
          if index &lt; 0:
              self.addItem(item)
          else:
              self.insertItem(index, item)
          self.setItemWidget(item, widget)
  
      def dropEvent(self, event):
          drop_index = self.indexAt(event.pos()).row()
          self.add_btn(index=drop_index)
          super(ReorderList, self).dropEvent(event)
  
      def dragEnterEvent(self, event):
          event.accept()
  
      def dragMoveEvent(self, event):
          event.accept()
  
      def onClick(self):
          print self.sender().text()
  
  
  class Test(QtWidgets.QMainWindow):
  
      def __init__(self, *args, **kwargs):
          super(Test, self).__init__(*args, **kwargs)
  
          self.list1 = QtWidgets.QListWidget()
          self.list1.setDragDropMode(
              QtWidgets.QAbstractItemView.DragDrop
          )
          self.list1.setSelectionMode(
              QtWidgets.QAbstractItemView.SingleSelection
          )
          self.list1.setDragDropMode(
              QtWidgets.QAbstractItemView.InternalMove
          )
          self.list1.setMaximumHeight(60)
          self.list2 = ReorderList()
          self.list2.setMaximumHeight(120)
          for name in ('item 1', 'item 2', 'item 3'):
              item = QtWidgets.QListWidgetItem(name)
              self.list1.addItem(item)
              self.list2.add_btn(text=name)
          self.btn = DragButton(text='Add list button')
          self.btn.clicked.connect(self.list2.add_btn)
  
          self.widget = QtWidgets.QWidget()
          self.setCentralWidget(self.widget)
          self.layout = QtWidgets.QVBoxLayout(self.widget)
          for item in (self.list1, self.list2, self.btn):
              self.layout.addWidget(item)
  
  
  if __name__ == '__main__':
      app = QtWidgets.QApplication(sys.argv)
      win = Test()
      win.show()
      sys.exit(app.exec_())
  </code></pre>
  
  <p>I'd like to be able to have a horizontal bar when inserting a widget in the QListWidget, and have the buttons that have been drug return to their default color.  </p>
  
  <p>Here are some similar links I could find that helped get me to this point:</p>
  
  <ul>
  <li><a href="https://stackoverflow.com/questions/41595014/dragndrop-custom-widget-items-between-qlistwidgets">Drag&#39;N&#39;Drop custom widget items between QListWidgets</a></li>
  <li><a href="https://stackoverflow.com/questions/25187444/pyqt-qlistwidget-custom-items">PyQt QListWidget custom items</a></li>
  <li><a href="https://stackoverflow.com/questions/44330207/pyqt-add-drag-drop-to-widget">PyQt - Add drag &amp; drop to widget</a></li>
  </ul>