Acknowledgments...xvii. Introduction... Chapter 1: Getting Started Chapter 2: Build a Hi-Lo Guessing Game App!... 19

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3 Brief Contents Acknowledgments...xvii Introduction... xix Chapter 1: Getting Started... 1 Chapter 2: Build a Hi-Lo Guessing Game App! Chapter 3: Creating a GUI for Our Guessing Game Chapter 4: Creating Your First Android App Chapter 5: Polishing Your App by Adding Menus and Preferences Chapter 6: Deciphering Secret Messages Chapter 7: Creating Advanced GUIs and Sharing Your App Chapter 8: Make Secret Messages a Phone App to Share with Friends! Chapter 9: Paint Colorful Bubbles with Your Mouse! Chapter 10: Adding Animation and Collision Detection with Timers Chapter 11: Making BubbleDraw a Multitouch Android App Appendix: Debugging and Avoiding Common Errors in Java Index

4 Acknowledgments xvii Introduction Why Should I Learn to Code?... xx Why Should I Learn Java?.... xx What s in This Book... xx What Tools Do I Need?... xxi Online Resources... xxi Start Now!... xxii xix 1 Getting Started 1 Java on Windows, macos, and Linux... 1 Installing Java 8 and 9 for Developers... 2 Installing the Eclipse IDE for Java Developers Setting Up Eclipse... 4 Installing the WindowBuilder Editor Customizing Eclipse s Look and Feel... 7 Installing Android Studio for Mobile App Development... 8 Getting to Know Java with JShell... 9 Running JShell Working with Java Expressions in JShell Declaring Java Variables in JShell Printing Output in Java JShell Commands What You Learned Build a Hi-Lo Guessing Game App! 19 Planning the Game Step-by-Step Creating a New Java Project Creating the HiLo Class Generating a Random Number Getting User Input from the Keyboard Making the Program Print Output Loops: Ask, Check, Repeat if Statements: Testing for the Right Conditions Adding a Play Again Loop Testing the Game What You Learned Programming Challenges #1: Expanding Your Range #2: Counting Tries #3: Playing MadLibs... 41

5 3 Creating a GUI for Our Guessing Game 43 Practicing with JShell Creating a GUI in Four Lines of Code Creating an Interactive GUI in 10 Lines of Code! Setting Up the GUI App in Eclipse GUI Design with Eclipse s WindowBuilder Editor Designing the User Interface Setting GUI Properties in the Properties Pane Customizing GUI Components in the Palette Pane Aligning GUI Elements Naming GUI Components for Coding Connecting the GUI to Your Java Code Adding a Method to Check the Player s Guess Getting Text from a JTextField Converting Strings to Numbers Starting a New Game Listening for User Events: Click to Guess! Setting Up the GUI Window Time to Play! Adding a Play Again Feature Improving the UX Allowing Users to Press Enter to Guess Automatically Removing Old Guesses Handling Bad User Input What You Learned Programming Challenges #1: Showing Users How Many Tries They Took #2: Showing and Hiding a Play Again Button #3: Creating a GUI MadLib Creating Your First Android App 75 Starting a New Android Studio App Project Building the GUI Layout in Design View Naming GUI Components in Android Studio Connecting the GUI to Java in Android Studio Adding Methods to Check the Guess and Begin a New Game Handling Events in Android Running the App on the Android Emulator Running the App on a Real Android Device Preparing Your Device Connecting Your Device Running the App on Your Device Improving the UX Centering the User s Guess in the Text Field Adding a Listener for the Enter Key Adding One More Finishing Touch What You Learned xii

6 Programming Challenges #1: Toast -ing to the Number of Tries #2: Adding Visual Appeal #3: Creating a MadLibs Mobile App Polishing Your App by Adding Menus and Preferences 109 Adding an Options Menu in Android Adding Items to the Menu s XML File Displaying the Options Menu Responding to User Selections Creating an Alert Dialog Pop-up for the About Screen Changing the Guessing Range Adding a Variable for the Range Using the range Variable Building the Dialog to Allow the User to Select the Range Storing User Preferences and Game Stats Storing and Retrieving the User s Preferred Range Storing the Number of Games Won What You Learned Programming Challenges #1: You Win Some, You Lose Some #2: Ratio of Wins to Losses Deciphering Secret Messages 125 The Caesar Cipher Setting Up the Secret Messages App Creating the Secret Messages Project in Eclipse Beginning to Code SecretMessages.java Messing with Strings Characters and Values in Java Encoding Just the Letters Closing the Scanner Adding a Custom Key Value Encoding Digits Running Command Line Apps Without Eclipse Finding Your Workspace Folders Opening a Command Line Window What You Learned Programming Challenges #1: Looping the Loop #2: Reversing and Encoding #3: Safely Handling Keys with try and catch xiii

7 7 Creating Advanced GUIs and Sharing Your App 147 Setting Up the Secret Messages GUI App Project Designing the GUI and Naming Components Coding the Secret Messages GUI App Creating the encode() Method Writing the Event Handler for the Encode/Decode Button Handling Bad Input and User Errors Building the main() Method and Running the App Improving the GUI Setting Line Wrap and Word Wrap Handling Bad Input and User Errors: Part Adding a Slider to the Secret Messages GUI Code Cracking with the Slider Bonus: Sharing Your App as a Runnable JAR File What You Learned Programming Challenges #1: Movin On Up! #2: Scrolling Away! #3: Changing the Text to Change the Slider Make Secret Messages a Phone App to Share with Friends! 175 Setting Up the Mobile GUI Designing the Mobile GUI Wiring the GUI to the Java Code Connecting the Encode Button to the encode() Method Testing the App Working with the SeekBar Running the App on the Emulator and on an Android Device Bonus: Customizing the Floating Action Button Receiving Secret Messages from Other Apps What You Learned Programming Challenges #1: Creating a Move Up Button #2: Changing the SeekBar s Progress Paint Colorful Bubbles with Your Mouse! 197 Creating the BubbleDraw Project Files Building the BubbleDraw Frame Creating a Class for Bubbles Defining a Bubble Designing a Bubble s Methods Storing Bubbles in an ArrayList Adding a Constructor to the BubblePanel Class Adding a Method to Draw on the Screen Testing the BubblePanel Class xiv

8 Handling Mouse Events from the User Creating a Reusable Event Listener Handling Clicks and Drags Bonus: Handling MouseWheel Events What You Learned Programming Challenges #1: No Bubble Too Small #2: PixelDraw! Adding Animation and Collision Detection with Timers 221 Copying the BubbleDraw Java Project to Create BubbleDrawGUI Renaming the Main Class and Java File Adding Transparency Adding Animation: Bubbles Rising! Adding a Timer Setting the Timer Preparing the Animation Starting the Timer Forever Blowing Bubbles: Adding Random Speed and Direction Building a GUI for Our Animated Drawing App Setting Up the GUI Panel and Buttons Coding the Clear and Pause/Start Buttons Bouncing off the Walls with Collision Detection A Soft Bounce A Hard Bounce Adding a Slider to Control the Animation Speed Customizing the Slider Implementing the Slider Event Handler What You Learned Programming Challenges #1: No Bubble Left Behind #2: Flexi-Draw! #3: PixelDraw Making BubbleDraw a Multitouch Android App 249 Setting Up the BubbleDraw Project Creating the BubbleView Constructor Adding the Animation Variables Creating the BubbleView() Constructor Preparing the Layout to Use BubbleView Modifying the Bubble Class Drawing in Android with the ondraw() Method Testing BubbleDraw with 100 Bubbles Adding testbubbles() Fixing the OnTouchListener Error Running the BubbleDraw App xv

9 Using Threaded Animation and Multitasking in Java Using Touch to Draw with Your Finger Using Multitouch to Draw with 10 Fingers at a Time! Testing Multitouch Events on an Android Device Changing the App Launcher Icon Creating a Custom App Icon Adding the Custom Icon to Your App Displaying Your New Icon Changing the App Name What You Learned Programming Challenges #1: Combining One-Finger and Multitouch Events, v #2: Combining One-Finger and Multitouch Events, v Appendix Debugging and Avoiding Common Errors in Java 273 Spelling and Case Correcting Typos in Eclipse Correcting Typos in Android Studio Avoiding Other Common Spelling Errors Comparison Trouble Grouping Symbols Quick Fixes in Eclipse Code Completion in Android Studio Summary Index 279 xvi