Python GUI Programming with Tkinter: Design and build functional and user-friendly GUI applications. 2 Ed

Preface....19

Who this book is for....20

What this book covers....21

To get the most out of this book....22

Get in touch....26

Introduction to Tkinter....28

Introducing Tkinter and Tk....29

Choosing Tkinter....29

Installing Tkinter....31

Installing Python 3.9 on Windows....31

Installing Python 3 on macOS....32

Installing Python 3 and Tkinter on Linux....32

Introducing IDLE....32

Using the shell mode of IDLE....33

Using the editor mode of IDLE....33

IDLE as a Tkinter example....34

Creating a Tkinter Hello World....36

An overview of basic Tkinter....39

Building a GUI with Tkinter widgets....39

Arranging our widgets with geometry managers....45

Making the form actually do something....50

Handling data with Tkinter control variables....53

Using control variables in a callback function....58

The importance of control variables....60

Summary....61

Designing GUI Applications....62

Analyzing a problem at ABQ AgriLabs....63

Assessing the problem....63

Gathering information about the problem....64

Interviewing the interested parties....65

Analyzing what we've found out....67

Information from the data originators....68

Information from the users of the application....70

Information from technical support....71

Information from the data consumer....72

Documenting specification requirements....73

Contents of a simple specification....73

Writing the ABQ data entry program specification....75

Designing the application....78

Deciding on input widgets....78

Grouping our fields....81

Laying out the form....82

Laying out the application....84

Evaluating technology options....86

Summary....88

Creating Basic Forms with Tkinter and Ttk Widgets....90

The Ttk widget set....90

The Label widget....92

The Entry widget....93

The Spinbox widget....94

The Checkbutton widget....95

The Radiobutton widget....97

The Combobox widget....98

The Text widget....99

Text widget indices....101

The Button widget....102

The LabelFrame widget....103

Implementing the application....105

First steps....106

Building the data record form....108

The Record Information section....108

The Environment Data section....111

The Plant Data section....112

Finishing the GUI....114

Writing the callback functions....115

The Reset function....115

The Save callback....116

Finishing up and testing....120

Summary....121

Organizing Our Code with Classes....123

A primer on Python classes....123

The advantages of using classes....124

Classes are an integral part of Python....124

Classes make relationships between data and functions explicit....125

Classes help create reusable code....125

Syntax of class creation....125

Attributes and methods....126

Magic attributes and methods....129

Public, private, and protected members....131

Inheritance and subclasses....133

Using classes with Tkinter....134

Improving Tkinter classes....135

Creating compound widgets....137

Building encapsulated components....139

Subclassing Tk....142

Rewriting our application using classes....145

Adding a StringVar to the Text widget....145

Passing in a variable....146

Synchronizing the widget to the variable....147

Synchronizing the variable to the widget....147

Creating a more advanced LabelInput()....149

Creating a form class....152

Creating an application class....158

Summary....161

Reducing User Error with Validation and Automation....163

Validating user input....163

Strategies to prevent data errors....164

Validation in Tkinter....165

The validate argument....166

The validatecommand argument....166

The invalidcommand argument....169

Creating validated widget classes....170

Creating a Date field....172

Implementing validated widgets in our GUI....176

Introducing the power of multiple inheritance....177

Building a validating mixin class....180

Building validating input widgets with ValidatedMixin....183

Requiring data....184

Creating a Date widget....184

A better Combobox widget....185

A range-limited Spinbox widget....188

Validating Radiobutton widgets....192

Updating our form with validated widgets....195

Implementing validation interaction between form widgets....197

Dynamically updating the Spinbox range....198

Dynamic disabling of fields....204

Displaying errors....206

Preventing form submission on error....207

Automating input....210

Date automation....211

Automating Plot, Lab, Time, and Technician....212

Summary....214

Planning for the Expansion of Our Application....215

Separating concerns....216

The MVC pattern....216

What is a model?....217

What is a view?....217

What is a controller?....218

Why complicate our design?....219

Structuring our application directory....220

Basic directory structure....220

The abq_data_entry.py file....221

The README.rst file....222

Populating the docs folder....223

Making a Python package....224

Splitting our application into multiple files....226

Creating the models module....226

Moving the widgets....233

Moving the views....234

Removing redundancy in our view logic....236

Using custom events to remove tight coupling....239

Creating the application file....241

Running the application....243

Using version control software....244

A super-quick guide to using Git....245

Initializing and configuring a Git repository....246

Adding and committing code....246

Viewing and using our commits....248

Summary....249

Creating Menus with Menu and Tkinter Dialogs....250

Solving problems in our application....251

Planning solutions to the issues....251

Implementing Tkinter dialogs....253

Error dialogs with the Tkinter messagebox....253

Showing error dialogs in ABQ Data Entry....256

Using filedialog....258

Using simpledialog and creating a custom dialog....262

Creating a Login dialog using simpledialog....263

Incorporating the LoginDialog in our class....266

Designing the application menu....269

The Tkinter Menu widget....270

Using Checkbutton and Radiobutton items....272

Implementing the ABQ application menu....275

Adding a Help menu....276

Adding a File menu....277

Adding a settings menu....280

Finishing the menu....283

Persisting settings....283

Building a model for settings persistence....285

Using the settings model in our application....289

Summary....291

Navigating Records with Treeview and Notebook....293

Implementing read and update in the model....293

Adding read and update to the CSVModel class....294

Implementing get_all_records()....295

Implementing get_record()....298

Adding update capability to save_record()....298

The Ttk Treeview....300

Anatomy of a Treeview....301

Building a file browser....302

Creating and configuring a Treeview....303

Populating a Treeview with data....305

Sorting Treeview records....308

Using Treeview virtual events....312

Implementing a record list with Treeview....313

Creating the RecordList class....314

Configuring a Treeview widget....315

Adding a scrollbar for the Treeview....317

Populating the Treeview....319

Adding the record list to the application....320

Modifying the record form for read and update....321

Adding a current record property....321

Adding a label to show what is being edited....322

Adding a load_record() method....322

Updating the application layout....324

The Ttk Notebook widget....325

Adding a notebook to our application....328

Adding and updating application callbacks....329

The _show_recordlist() method....329

The _populate_recordlist() method....330

The _new_record() method....332

The _open_record() method....333

The _on_save() method....334

Main menu changes....334

Testing our program....335

Summary....336

Improving the Look with Styles and Themes....338

Working with images in Tkinter....339

Tkinter PhotoImage....339

PhotoImage and variable scope....340

Using Pillow for extended image support....341

Adding the company logo to ABQ Data Entry....345

Dealing with the image path problem....346

Setting a window icon....349

Adding icons to buttons and menus....350

Using BitmapImage....354

Styling Tkinter widgets....356

Widget color properties....357

Using widget properties on the MainMenu....357

Styling widget content with tags....360

Styling our record list with tags....363

Working with fonts in Tkinter....367

Configuring Tkinter fonts....367

Configuring fonts with strings and tuples....367

The font module....368

Giving users font options in ABQ Data Entry....373

Styling Ttk widgets....376

TTk styling breakdown....376

Exploring a Ttk widget....377

Using themes....383

Adding some color to ABQ Data Entry....384

Adding styles to individual form widgets....386

Fixing the error colors....389

Styling input widgets on error....390

Setting themes....393

Building a theme selector....393

Summary....396

Maintaining Cross-Platform Compatibility....398

Writing cross-platform Python....398

Filenames and file paths across platforms....399

Path separators and drives....399

Case sensitivity....403

Symbolic links....404

Path variables....405

Inconsistent library and feature support....407

Python's platform-limited libraries....407

Checking low-level function compatibility....408

The dangers of the subprocess module....409

Text file encodings and formats....410

Graphical and console modes....411

Writing code that changes according to the platform....413

Writing cross-platform Tkinter....416

Tkinter version differences across platforms....416

Application menus across platforms....417

Menu widget capabilities....417

Menu guidelines and standards....421

Menus and accelerator keys....423

Cross-platform fonts....423

Cross-platform theme support....424

Window zoomed state....424

Improving our application's cross-platform compatibility....425

Storing preferences correctly....425

Specifying an encoding for our CSV file....427

Making platform-appropriate menus....428

Preparing our MainMenu class....428

Adding accelerators....432

Building the Windows menu....434

Building the Linux menu....436

Building the macOS menu....437

Creating and using our selector function....441

Summary....443

Creating Automated Tests with unittest....444

Automated testing basics....444

A simple unit test....445

The unittest module....447

Writing a test case....448

TestCase assertion methods....450

Fixtures....452

Using Mock and patch....453

Running multiple unit tests....455

Testing Tkinter code....456

Managing asynchronous code....456

Simulating user actions....457

Specifying an event sequence....457

Managing focus and grab....459

Getting widget information....460

Writing tests for our application....461

Testing the data model....461

Testing file reading in get_all_records()....463

Testing file saving in save_record()....465

More tests on the models....468

Testing our Application object....468

Testing our widgets....473

Unit testing the ValidatedSpinbox widget....474

Integration testing the ValidatedSpinbox widget....476

Testing our mixin class....482

Summary....484

Improving Data Storage with SQL....485

PostgreSQL....486

Installing and configuring PostgreSQL....486

Configuring PostgreSQL using the GUI utility....487

Configuring PostgreSQL using the command line....488

Modeling relational data....489

Primary keys....489

Using surrogate primary keys....490

Normalization....492

First normal form....492

Second normal form....494

Third normal form....495

More normalization forms....496

Entity-relationship diagrams....496

Assigning data types....498

Creating the ABQ database....500

Creating our tables....500

Creating the lookup tables....500

The lab_checks table....502

The plot_checks table....503

Creating a view....504

Populating the lookup tables....506

Connecting to PostgreSQL with psycopg2....506

psycopg2 basics....507

Parameterized queries....509

Special cursor classes....512

Integrating SQL into our application....513

Creating a new model....513

Saving data....518

Getting the current seed sample for the plot....521

Adjusting the Application class for the SQL backend....522

Implementing SQL logins....523

Updating the Application._on_save() method....524

Removing file-based code....525

Adjusting the DataRecordForm for SQL data....526

Reordering fields....526

Fixing the load_record() method....527

Improving auto-fill....527

Updating the RecordList for the SQLModel....529

We're done!....532

Summary....533

Connecting to the Cloud....534

HTTP using urllib....534

HTTP transaction fundamentals....535

HTTP status codes....536

Basic downloading with urllib.request....536

Generating POST requests....538

Downloading weather data to ABQ Data Entry....539

Creating a weather data model....539

Parsing the XML weather data....541

Implementing weather data storage....544

Adding the GUI elements for weather download....547

RESTful HTTP using requests....550

Understanding RESTful web services....550

The Python requests library....552

Installing and using requests....552

Interacting with authenticated sites using Session....554

The requests.Response object....555

Implementing a REST backend....556

The authenticate() method....559

The upload_file() method....561

The check_file() method....561

The get_file() method....562

Integrating REST upload into the application....563

Creating a CSV extract....563

Creating the upload callback....564

Finishing up....568

SFTP using paramiko....570

Setting up SSH services for testing....570

Installing and using paramiko....571

Using paramiko....571

Inspecting our connection....574

Using SFTP....574

Implementing an SFTP model....576

Uploading files....578

Checking a file's existence....580

Using SFTPModel in our application....581

Finishing up....584

Summary....585

Asynchronous Programming with Thread and Queue....587

Tkinter's event queue....588

Event queue control....588

The update() methods....588

The after() methods....589

Common uses of event queue control....591

Smoothing out display changes....591

Mitigating GUI freezes....592

Running code in the background with threads....595

The threading module....596

Tkinter and thread safety....597

Converting our network functions to threaded execution....598

Using the threaded uploader....600

Passing messages using a queue....601

The Queue object....602

Using queues to communicate between threads....603

Adding a communication queue to our threaded uploader....606

Creating a communications protocol....607

Sending messages from the uploader....609

Handling queue messages....610

Using locks to protect shared resources....612

Understanding the Lock object....613

Using a Lock object to prevent concurrent uploads....615

Threading and the GIL....616

Summary....617

Visualizing Data Using the Canvas Widget....618

Drawing and animation with Tkinter's Canvas....618

Drawing on the Canvas....619

Rectangles and squares....619

Ovals, circles, and arcs....621

Lines....622

Polygons....623

Text....624

Images....624

Tkinter widgets....625

Canvas items and state....626

Canvas object methods....626

Scrolling the Canvas....628

Animating Canvas objects....631

Setting up the playing field....632

Setting our players....633

Animating the racers....634

Running the game loop and detecting a win condition....639

Creating simple graphs using Canvas....642

Creating the model method....643

Creating the chart view....644

Updating the application....650

Advanced graphs using Matplotlib....652

Data model method....652

Creating the bubble chart view....654

Updating the Application class....657

Summary....659

Packaging with setuptools and cxFreeze....661

Creating distributable packages with setuptools....661

Preparing our package for distribution....662

Creating a requirements.txt file....662

Creating a pyproject.toml file....664

Adding a license file....665

Making our package executable....665

Configuring a setup.py script....666

Basic metadata arguments....667

Packages and dependencies....668

Adding extra files....669

Defining commands....670

Testing the configuration....671

Creating and using source distributions....672

Testing our source distribution....672

Building a wheel distribution....673

Creating executables with cx_Freeze....675

First steps with cx_Freeze....676

The build_exe options....677

Including external files....678

Building executables....679

Cleaning up the build....680

Building Windows executables with cx_Freeze....681

Building a Windows installer file....682

Building macOS executables with cx_Freeze....685

Building macOS application bundles....685

Building macOS .dmg files....686

Summary....687

Appendices....688

A: A Quick Primer on reStructuredText....689

The reStructuredText markup language....690

Document structure....690

Lists....692

Character styles....693

Blocks and quotes....694

Tables....695

Converting RST to other formats....696

Other ways to render RST....699

B: A Quick SQL Tutorial....701

SQL concepts....701

Syntax differences from Python....702

SQL operations and syntax....703

Defining tables and inserting data....703

Retrieving data from tables....706

Updating rows, deleting rows, and more WHERE clauses....708

Subqueries....710

Joining tables....711

Managing transactions....715

Learning more....717

Other Books You May Enjoy....719

Index....768

Tkinter is widely used to build GUIs in Python due to its simplicity. In this book, you'll discover Tkinter's strengths and overcome its challenges as you learn to develop fully featured GUI applications.

Python GUI Programming with Tkinter, Second Edition, will not only provide you with a working knowledge of the Tkinter GUI library, but also a valuable set of skills that will enable you to plan, implement, and maintain larger applications. You'll build a full-blown data entry application from scratch, learning how to grow and improve your code in response to continually changing user and business needs.

You'll develop a practical understanding of tools and techniques used to manage this evolving codebase and go beyond the default Tkinter widget capabilities. You'll implement version control and unit testing, separation of concerns through the MVC design pattern, and object-oriented programming to organize your code more cleanly.

You'll also gain experience with technologies often used in workplace applications, such as SQL databases, network services, and data visualization libraries. Finally, you'll package your application for wider distribution and tackle the challenge of maintaining cross-platform compatibility.

What you will learn

• Produce well-organized, functional, and responsive GUI applications
• Extend the functionality of existing widgets using classes and OOP
• Plan wisely for the expansion of your app using MVC and version control
• Make sure your app works as intended through widget validation and unit testing
• Use tools and processes to analyze and respond to user requests
• Become familiar with technologies used in workplace applications, including SQL, HTTP, Matplotlib, threading, and CSV
• Use PostgreSQL authentication to ensure data security for your application

Who this book is for

This book is for programmers who understand the syntax of Python, but do not yet have the skills, techniques, and knowledge to design and implement a complete software application. A fair grasp of basic Python syntax is required.