A QLineEdit with additional decorations :
- a background text, visible when the line edit doesn’t contain any text
- a validity, which will trigger the background color
Use the user_input method to get the text that was entered by the user.
Note : since QT 4.7 the background text could be replaced with the setPlaceholderText on a QLineEdit
Set the text to be displayed in the background when the line input does not contain any text :param background_text: the text to be shown, None if no text should be shown