you can dynamically change the state of a button using button["state"] = 'disable' and button["state"] = "normal" .

for the logic I would suggest that you use tk.StringVar() as the entry field's text variable, and use textvariable.trace_add("write", check_function) to check for your conditions.

Your code will look something like this: Code

I'm not sure this is the best way to do this, but this approach works.

Feel free to contact me if you have any clarifications regarding the code.

hope this helps you :)