Tkinter window won't get focus because of pyHook mouse LeftDown function

Question

so I'm trying to open a tkinter window through sensing left clicks from the mouse using pyHook, and I want the newly opened window to get the focus. The problem is that no matter what focus method I try, the current window will always retain the focus instead of the focus switching to the new tkinter window. Here's the code:

from tkinter import *
import pyHook
import pythoncom        

def open_GUI():
root = Tk()
root.title('test')
entry_box = Entry(root, font=("Calibri", 11))
entry_box.focus()
entry_box.pack(fill=X, side=RIGHT, expand=True)
root.after(1, lambda: root.focus_set())
root.mainloop()
return True


def MouseLeftDown_Func(event):
    print('mouse')
    open_GUI()
    return True


def KeyDown_Func(event):
    print('key')
    return True


hooks_manager = pyHook.HookManager()
hooks_manager.KeyDown = KeyDown_Func
hooks_manager.MouseLeftDown = MouseLeftDown_Func
hooks_manager.HookKeyboard()
hooks_manager.HookMouse()
pythoncom.PumpMessages()

I think the issue is that when I left click on the current window the focus is prioritized to the window that was recently clicked (the current window), and any command calling for a tkinter window focus is ignored.

Does anyone know how I can switch the focus to the new tkinter window after the left click?

Answer 1

I replaced the other solution with this one after importing pyhook. It is a bit complex, but when you're trying to steal the keyboard focus, that's what happens. There may be an easier way to do this. The key to this solution is telling the application to set the root window as foreground before the entry is created, but within an event. If you're not using windows, there's a Linux solution too.

from ctypes import Structure, c_ulong, byref, c_char_p, windll
from tkinter import *
import pyHook
import pythoncom

class POINT(Structure):
    _fields_ = [("x", c_ulong), ("y", c_ulong)]

def open_GUI():
    root = Tk()
    root.title('test')
    root.update()
    root.after(20, lambda r=root: createEntry(r))
    root.mainloop()
    return True

def setRootForeground(root):
    # Get window coordinates
    x = root.winfo_rootx() + 1
    y = root.winfo_rooty() + 1
    # Move the mouse cursor to x,y
    windll.user32.SetCursorPos(x, y)
    # Get the pointer coordinates into a Windows-compatible format
    pt = POINT()
    windll.user32.GetCursorPos(byref(pt))
    # Get the window handle under the pointer -- should be root.
    hwnd = windll.user32.WindowFromPoint(pt)
    # Make it the foreground window
    windll.user32.SetForegroundWindow(hwnd)

def createEntry(root):
    setRootForeground(root)
    root.focus_set()
    entry_box = Entry(root, font=("Calibri", 11))
    entry_box.pack(fill=X, side=RIGHT, expand=True)
    entry_box.focus_set()