A Complete PySimpleGUI Program (Getting The Gist)

Before diving into details, here's a description of what PySimpleGUI is/does and why that is so powerful.

You keep hearing "custom window" in this document because that's what you're making and using... your own custom windows.

ELEMENTS is a word you'll see everywhere... in the code, documentation, ... Elements == PySimpleGUI's Widgets. As to not confuse a tkinter Button Widget with a PySimpleGUI Button Element, it was decided that PySimpleGUI's Widgets will be called Elements to avoid confusion.

Wouldn't it be nice if a GUI with 3 "rows" of Elements were defined in 3 lines of code? That's exactly how it's done. Each row of Elements is a list. Put all those lists together and you've got a window.

What about handling button clicks and stuff. That's 4 lines of the code below beginning with the while loop.

Now look at the layout variable and then look at the window graphic below. Defining a window is taking a design you can see visually and then visually creating it in code. One row of Elements = 1 line of code (can span more if your window is crowded). The window is exactly what we see in the code. A line of text, a line of text and an input area, and finally ok and cancel buttons.

This makes the coding process extremely quick and the amount of code very small

import PySimpleGUI as sg
sg.theme('DarkAmber')   # Add a little color to your windows
# All the stuff inside your window. This is the PSG magic code compactor...
layout = [  [sg.Text('Some text on Row 1')],
            [sg.Text('Enter something on Row 2'), sg.InputText()],
            [sg.OK(), sg.Cancel()]]

# Create the Window
window = sg.Window('Window Title', layout)
# Event Loop to process "events"
while True:             
    event, values = window.read()
    if event in (sg.WIN_CLOSED, 'Cancel'):
        break

window.close()

You got to admit that the code above is a lot more "fun" looking that tkinter code you've studied before. Adding stuff to your GUI is trivial. You can clearly see the "mapping" of those 3 lines of code to specific Elements laid out in a Window. It's not a trick. It's how easy it is to code in PySimpleGUI. With this simple concept comes the ability to create any window layout you wish. There are parameters to move elements around inside the window should you need more control.

It's a thrill to complete your GUI project way ahead of what you estimated. Some people take that extra time to polish their GUI to make it even nicer, adding more bells and whistles because it's so easy and it's a lot of fun to see success after success as you write your program.

Some are more advanced users and push the boundaries out and extend PySimpleGUI using their own extensions.

Others, like IT people and hackers, are busily cranking out GUI program after GUI program, and creating tools that others can use. Finally, there's an easy way to throw a GUI onto your program and give it to someone. It's a pretty big leap in capability for some people. It's GREAT to hear these successes. It's motivating for everyone in the end. Your success can easily motivate the next person to give it a try and also potentially be successful.

Usually, there's a one to one mapping of a PySimpleGUI Element to a GUI Widget. A "Text Element" in PySimpleGUI == "Label Widget" in tkinter. What remains constant for you across all PySimpleGUI platforms is that no matter what the underlying GUI framework calls the thing that places text in your window, you'll always use the PySimpleGUI Text Element to access it.

The final bit of magic is in how Elements are created and changed.

So far you've seen simple layouts with no customization of the Elements. Customizing and configuring Elements is another place PySimpleGUI utilizes the Python language to make your life easier.

What about Elements that have settings other than the standard system settings? What if I want my Text to be blue, with a Courier font on a green background. It's written quite simply:

Text('This is some text', font='Courier 12', text_color='blue', background_color='green')

The Python named parameters are extensively in PySimpleGUI. They are key in making the code compact, readable, and trivial to write.

As you'll learn in later sections that discuss the parameters to the Elements, there are a LOT of options available to you should you choose to use them. The Text Element has 15 parameters that you can change. This is one reason why PyCharm is suggested as your IDE... it does a fantastic job of displaying documentation as you type in your code.

That's The Basics

What do you think? Easier so far than your previous run-ins with GUIs in Python? Some programs, many in fact, are as simple as this example has been.

But PySimpleGUI certainly does not end here. This is the beginning. The scaffolding you'll build upon.