How to show alpha channel in PyQt5 QColorDialog

Question

I have tried this code:

def open_color_dialog(self, label):
    dialog = QColorDialog()
    dialog.setOption(QColorDialog.ShowAlphaChannel, on=True)
    print(dialog.testOption(QColorDialog.ShowAlphaChannel)) #returning True
    color = dialog.getColor()

    if color.isValid():
        label.setStyleSheet("background-color:" + color.name() + ";")

But this code didn't work. How can I show alpha channel ?

Answer 1

The problems are:

• The dialog object of the QColorDialog class has been created but you use the static QColorDialog::getColor() method that creates a new QColorDialog object that is displayed.

  def open_color_dialog(self, label):
      dialog = QColorDialog()
      dialog.setOption(QColorDialog.ShowAlphaChannel, on=True)
      if dialog.exec_() == QDialog.Accepted:
          color = dialog.selectedColor()
          if color.isValid():
              # ...
  

  or

  def open_color_dialog(self, label):
      color = QColorDialog.getColor(options=QColorDialog.ShowAlphaChannel)
      if color.isValid():
          # ...
  

• The name method of QColorDialog by default will return only rgb, if you want to get argb then you must use QColor.HexArgb as parameter:

  label.setStyleSheet(
      "background-color:{};".format(color.name(QColor.HexArgb))
  )