wxPython in Action: event-driven GUI programming

To every Jane and Joe Programmer,
chained to their computer, burning the midnight oil,
striving to make a dream come true

preface xix
acknowledgments xxii
about this book xxiv

Part 1 Introduction to wxPython 1

1 Welcome to wxPython 3

1.1 Getting started with wxPython 5

1.2 Creating the bare-minimum wxPython program 7

Importing wxPython 9

Working with applications and frames 11

1.3 Extending the bare-minimum wxPython program 12

1.4 Creating the final hello.py program 15

1.5 What can wxPython do? 17

1.6 Why choose wxPython? 19

Python programmers 19

wxWidget users 20

New users 20

1.7 How wxPython works 21

The Python language 21

The wxWidgets toolkit 22

Putting it together: the wxPython toolkit 25

1.8 Summary 27

2 Giving your wxPython program a solid foundation 29

2.1 What do I need to know about the required objects? 30

2.2 How do I create and use an application object? 31

Creating a wx.App subclass 31

Understanding the application object lifecycle 34

2.3 How do I direct output from a wxPython program? 35

Redirecting output 35

Modifying the default redirect behavior 37

2.4 How do I shut down my wxPython application? 38

Managing a normal shutdown 38

Managing an emergency shutdown 39

2.5 How do I create and use the top-level window object? 39

Working with wx.Frame 40

Working with wxPython IDs 42

Working with wx.Size and wx.Point 43

Working with wx.Frame styles 44

2.6 How do I add objects and subwindows to a frame? 47

Adding widgets to a frame 47

Adding a menubar, toolbar, or status bar to a frame 49

2.7 How can I use common dialogs? 51

2.8 What are some common errors with application objects and frames? 53

2.9 Summary 54

3 Working in an event-driven environment 56

3.1 What terminology do I need to understand events? 57

3.2 What is event-driven programming? 58

Coding event handlers 60

Designing for event-driven programs 61

Event triggers 62

3.3 How do I bind an event to a handler? 63

Working with the wx.EvtHandler methods 65

3.4 How are events processed by wxPython? 68

Understanding the event handling process 69

Using the Skip() method 75

3.5 What other event properties are contained in the application object? 77

3.6 How can I create my own events? 77

Defining a custom event for a custom widget 78

3.7 Summary 81

4 Making wxPython easier to handle with PyCrust 83

4.1 How do I interact with a wxPython program? 84

4.2 What are the useful features of PyCrust? 86

Autocompletion 87

Calltips and parameter defaults 88

Syntax highlighting 89

Python help 90

Command recall 91

Cut and paste 92

Standard shell environment 93

Dynamic updating 94

4.3 What do the PyCrust notebook tabs do? 95

Namespace tab 95

Display tab 97

Calltip tab 97

Session tab 98

Dispatcher tab 98

4.4 How can I wrap PyCrust around my wxPython application? 99

4.5 What else is in the Py package? 104

Working with the GUI programs 104

Working with the support modules 105

4.6 How can I use modules from the Py package in my wxPython programs? 112

4.7 Summary 115

5 Creating your blueprint 116

5.1 How can refactoring help me improve my code? 117

A refactoring example 118

Starting to refactor 121

More refactoring 122

5.2 How do I keep the Model and View separate in my program? 126

What is a Model-View-Controller system? 126

A wxPython model: PyGridTableBase 128

A custom model 136

5.3 How do you unit-test a GUI program? 140

The unittest module 140

A unittest sample 141

Testing user events 143

5.4 Summary 145

6 Working with the basic building blocks 146

6.1 Drawing to the screen 148

How do I draw on the screen? 148

6.2 Adding window decorations 155

How do I add and update a status bar? 155

How do I include a submenu or checked menu? 158

How do I include a toolbar? 161

6.3 Getting standard information 165

How do I use standard file dialogs? 165

How do I use a standard color picker? 169

6.4 Making the application look nice 170

How do I lay out widgets? 170

How do I build an about box? 178

How do I build a splash screen? 180

6.5 Summary 181

Part 2 Essential wxPython 183

7 Working with the basic controls 185

7.1 Displaying text 186

How do I display static text? 186

How can I get the user to enter text? 189

How do I change the text without user input? 192

How do I create a multi-line or styled text control? 193

How do I create a font? 196

Can I have styled text if my platform doesnít support rich text? 197

What if my text control doesnít match my string? 198

How do I respond to text events? 199

7.2 Working with buttons 199

How do I make a button? 200

How do I make a button with a bitmap? 201

How do I create a toggle button? 202

Whatís a generic button, and why should I use one? 203

7.3 Entering and displaying numbers 205

How do I make a slider? 205

How can I get those neat up/down arrow buttons? 208

How can I make a progress bar? 210

7.4 Giving the user choices 211

How do I create a checkbox? 211

How can I create a group of radio buttons? 212

How can I create a list box? 216

Can I combine a checkbox and a list box? 219

What if I want a pull-down choice? 220

Can I combine text entry and a list? 221

7.5 Summary 222

8 Putting widgets in frames 224

8.1 The life of a frame 225

How do I create a frame? 225

What are some different frame styles? 227

How do I create a frame with extra style information? 230

What happens when I close a frame? 232

8.2 Using frames 234

What are the methods and properties of wx.Frame? 234

How do I find a subwidget of a frame? 237

How do I create a frame with a scrollbar? 238

8.3 Alternative frame types 242

How do I create an MDI frame? 242

Whatís a mini-frame and why would I use it? 244

How do I make a non-rectangular frame? 245

How can I drag a frame without a title bar? 248

8.4 Using splitter windows 250

Creating a splitter window 250

A splitter example 251

Changing the appearance of the splitter 253

Manipulating the splitter programmatically 254

Responding to splitter events 255

8.5 Summary 256

9 Giving users choices with dialogs 258

9.1 Working with modal dialogs 259

How do I create a modal dialog? 259

How do I create an alert box? 261

How do I get short text from the user? 264

How can I display a list of choices in a dialog? 266

How can I display progress? 267

9.2 Using standard dialogs 269

How can I use a file picker? 269

How can I use a font picker? 273

How can I use a color picker? 275

Can I allow the user to browse images? 277

9.3 Creating a wizard 278

9.4 Showing startup tips 281

9.5 Using validators to manage data in a dialog 282

How do I use a validator to ensure correct data? 282

How do I use a validator to transfer data? 286

How do I validate data as it is entered? 288

9.6 Summary 291

10 Creating and using wxPython menus 293

10.1 Creating Menus 294

How do I create a menu bar and attach it to a frame? 295

How do I create a menu and attach it to the menu bar? 295

How do I add items to a pull-down menu? 297

How do I respond to a menu event? 301

10.2 Working with menu items 303

How do I find a specific menu item in a menu? 303

How do I enable or disable a menu item? 306

How do I associate a menu item with a keyboard shortcut? 307

How do I create a toggle menu item with a checkbox or radio button? 311

10.3 Sprucing up your menus 313

How do I create a submenu? 313

How do I create a pop-up menu? 315

How can I create fancier menus? 317

10.4 Usability guidelines for menus 319

Keeping menus uniform in length 319

Creating logical item groups 319

10.5 Summary 321

11 Placing widgets with sizers 323

11.1 Whatís a sizer? 324

11.2 Basic sizers with the grid sizer 326

What is a grid sizer? 327

How do you add or remove children from a sizer? 329

How do sizers manage the size and alignment of their children? 331

Can I specify a minimum size for my sizer or its children? 334

How do sizers manage the border around each child? 336

11.3 Using the other sizer types 337

Whatís a flex grid sizer? 337

Whatís a grid bag sizer? 341

Whatís a box sizer? 345

Whatís a static box sizer? 349

11.4 Can I see a real-world example of sizers in action? 350

11.5 Summary 354

12 Manipulating basic graphical images 356

12.1 Working with images 357

How do I load images? 357

What can I do with an image? 361

How can I change cursors? 364

12.2 Dealing with device contexts 367

What is a device context, and how can I create one? 367

How do I draw to a device context? 371

How do I draw images to the context? 376

How can I draw text to the context? 379

12.3 Graphics manipulation 381

How do I manage the foreground drawing pen? 381

How do I manage the background drawing brush? 384

How can I manage logical and physical device coordinates? 385

What color names are predefined? 387

12.4 Summary 388

Part 3 Advanced wxPython 391

13 Building list controls and managing items 393

13.1 Building a list control 394

What is icon mode? 394

What is small icon mode? 395

What is list mode? 396

What is report mode? 397

How do I create a list control? 398

13.2 Managing items in a list 400

What is an image list and how do I add images to it? 400

How can I add and delete items from a list? 402

13.3 Responding to users 405

How can I respond to a user selection in a list? 405

How can I respond to a user selection in a column header? 407

13.4 Editing and sorting list controls 411

How can I edit a label? 411

How can I sort my list? 413

How can I learn more about list controls? 416

13.5 Creating a virtual list control 420

13.6 Summary 423

14 Coordinating the grid control 425

14.1 Creating your grid 426

How do I create a simple grid? 426

How do I create a grid with a grid table? 429

14.2 Working with your grid 432

How do I add and delete rows, columns, and cells? 432

How do I manage the row and column headers of a grid? 433

How can I manage the size of grid elements? 436

How can I manage which cells are selected or visible? 440

How do I change the color or font of a grid cell? 442

14.3 Custom renderers and editors 445

How do I use a custom cell renderer? 445

How do I edit a cell? 449

How do I use a custom cell editor? 450

14.4 Capturing user events 455

How can I capture user mouse selections? 455

How can I capture user keyboard navigation? 457

14.5 Summary 458

15 Climbing the tree control 460

15.1 Creating tree controls and adding items 461

How do I add a root? 463

How do I add more items to the tree? 463

How do I manage items? 464

15.2 What styles control the display of the tree control? 465

15.3 Sorting elements of a tree control 467

15.4 Controlling the image for each item 468

15.5 Navigating the tree programmatically 471

15.6 Managing the tree selection 472

15.7 Controlling which items are visible 473

15.8 Making a tree control user editable 477

15.9 Responding to other user events from a tree control 478

15.10 Using a tree list control 480

15.11 Summary 482

16 Incorporating HTML into your application 485

16.1 Displaying HTML 486

How can I display HTML in a wxPython window? 486

How can I display HTML from a file or URL? 488

16.2 Manipulating the HTML window 490

How can I respond to a user click on an active link? 490

How can I change an HTML window programmatically? 491

How can I display the page title in a frameís title bar? 493

How can I print an HTML page? 495

16.3 Extending the HTML window 496

How does the HTML parser work? 496

How can I add support for new tags? 498

How can I support other file formats? 501

How can I get a more fully featured HTML Widget? 502

16.4 Summary 503

17 The wxPython printing framework 504

17.1 How do I print in wxPython? 505

Understanding the printout lifecycle 506

Print framework in action 507

Working with wx.Printout methods 511

17.2 How do I display the print dialog? 512

Creating a print dialog 512

17.3 How do I display the page setup dialog? 515

Creating a page setup dialog 515

Working with page setup properties 516

17.4 How do I print something? 518

17.5 How can I perform a print preview? 519

17.6 Summary 520

18 Using other wxPython functionality 521

18.1 Putting objects on the clipboard 522

Getting data in the clipboard 522

Manipulating data in the clipboard 523

Retrieving text data from the clipboard 524

The clipboard in action 524

Passing other data formats 526

18.2 Being the source of a drag and drop 527

Dragging in action 529

18.3 Being the target of a drag and drop 530

Using your drop target 531

Dropping in action 533

18.4 Transferring custom objects 534

Transferring a custom data object 534

Retrieving a custom object 535

Transferring an object in multiple formats 535

18.5 Setting timed events using wx.Timer 536

Generating EVT_TIMER events 536

Learning other timer uses 539

18.6 Creating a multithreaded wxPython application 539

Working with the global function wx.CallAfter() 540

Managing thread communication with the queue object 543

Developing your own solution 543

18.7 Summary 544

index 545

DESCRIPTION

If you add the powerful wxWidgets toolkit to Python, you get wxPython: an open source GUI framework with a well-deserved reputation for simplicity and ease of use. wxPython lets you build cross-platform applications that have robust, highly functional graphical user interfaces.

The first book on the subject, wxPython in Action offers a friendly tutorial to get you started, a detailed guide to best practices, and an extensive reference for wxPython’s large widget library. It covers an impressive amount of information delivered at a measured pace, encouraging experimentation and learning by doing.

The book’s direct, no-nonsense style makes for an easy introduction to the concepts. It offers a complete discussion of when, why, and how to use the many widgets in the toolkit. And it includes dozens of handy reference tables so you can easily look up object properties, methods, and events. Co-authored by wxPython creator Robin Dunn, wxPython in Action is the authoritative book on the subject.

What’s Inside

• Create professional GUIs with wxPython
• Program in an event-oriented framework
• Use wxPython sizers for your layout
• Refactor and unit test to improve your programs
• A reference to wxPython’s powerful widget set

ABOUT THE AUTHORS…

Noel Rappin is a senior software engineer at Motorola and a leading Python practitioner. He has a Ph.D. from the Georgia Institute of Technology and lives in Chicago, IL.

A veteran of the software industry for almost two decades, Robin Dunn is the creator and maintainer of wxPython. Geographically, he is to be found in or between Portland, OR and Vancouver, WA.

About Manning’s Early Access Program (MEAP)

Complete ebook now avaliable!

Chapter 1 Welcome to wxPython Chapter 2 Giving your wxPython program a solid foundation Chapter 3 Working in an event-driven environment Chapter 4 Making wxPython easier to handle with PyCrust Chapter 5 Creating your blueprint Chapter 6 Working with the basic building blocks Chapter 7 Working with the basic controls Chapter 8 Putting widgets in frames Chapter 9 Giving users choices with dialogs

Chapter 10 Creating and using wxPython menus Chapter 11 Placing widgets with sizers Chapter 12 Manipulating basic graphical images Chapter 13 Building list controls and managing items Chapter 14 Coordinating the grid control Chapter 15 Climbing the tree control Chapter 16 Incorporating HTML into your application Chapter 17 The wxPython printing framework Chapter 18 Using other wxPython functionality

wxPython in Action is now available through the Manning Early Access Program (MEAP), our exclusive subscription program that delivers chapters long before the hard copy hits the shelves! MEAP costs nothing extra but you get what you need now! MEAP gives you two ordering options:

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