How to set focus to the old window on button click in PyQt5 Python?

Question

My Current Project is to create a On Screen Keyboard for my personal usage with my personal functionality. I made gui and primary function in PyQt5 with Python. I managed to type the letter on button click with pyautogui.write() method. But the problem is, where I want to type there is no focus. suppose I want to write on chrome's address bar or any other input field on my monitor. when I click on button to type a letter, chrome lost focus. I want to set focus to the old window while press on any button. I searched on google about this but didn't found any answer. How can i set focus to old window? or is there any better way to type on focus lost state?

Answer 1

You should not try to "set the focus back", as it would be almost impossible to know what window had the focus before (and a new window might raise in the meantime). What you should actually do is to prevent your window to get focus at all, thus avoiding it to steal focus from the others.

In order to achieve this, you must set the appropriate window flag (or initialize the widget with it using the flags keyword argument), which for this is Qt.WindowDoesNotAcceptFocus .
Note that you might also want to set the Qt.WindowStaysOnTopHint in order to always keep your window above the others:

class MyKeyboard(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setWindowFlags(
            QtCore.Qt.WindowDoesNotAcceptFocus
            | QtCore.Qt.WindowStaysOnTopHint
        )