Python code: GUI guizero demo PushButton

# This Python code is a basic demo of the GUI guizero (with PushButton trigger)
# guizero works with tkinter but simpler with extra widgets eg. Slider
# https://lawsie.github.io/guizero/slider/
# eventgui.py
# 2 buttons .. 2 actions. Read text fields and open alert-type info box <OK>

# Import .. GUI widgets etc
from guizero import App, TextBox, PushButton, Text, info
import math

app = App( title="Synopsis of You ++", bg = "#FFFF00", height = 400, width = 600 )

# Event Handler functions ------------------
def btn_go_clicked():  # on PushButton click -> get values from TextBox(es)
    likeAnimal = txtAnimal.value
    if (likeAnimal == ""):
        appendStr = ", please tell me more .."
    else:
        appendStr = " .. you like " + likeAnimal

    info("Greetings","Hello " + txt_name.value + appendStr)

def btn_alt_clicked():
    #info("Maths Fact","PI is " + "3.1416 to 4 dp.")
    outStr = "PI is {0:.5f}".format(math.pi) # format float into a string
    info("Maths Fact", outStr)

# GUI widgets -----------
lbl_name = Text(app, text="Hello. What's your name?", color="red", size=22)
txt_name = TextBox(app, width=50)

lblAnimal = Text(app, text="Please name an animal that you like ?")
txtAnimal = TextBox(app, width=40)

btn_go   = PushButton(app, command=btn_go_clicked, text="Synopsis ..", padx=8,pady=7)
btn_fact = PushButton(app, command=btn_alt_clicked, text="Maths fact ..", padx=8,pady=7)

# change parameters of widgets
btn_go.bg   ="#33FF55"
btn_fact.bg ="#33FFAA"
# Show the GUI on the screen
app.display()