- Learning Java by Building Android Games - Second Edition
- Table of Contents
- Learning Java by Building Android Games Second Edition
- Contributors
- Preface
- 1. Java, Android and Game Development
- What's new in the second edition?
- Why Java, Android and Games?
- The games you will build
- How Java and Android work
- Setting up Android Studio
- Starting the first project: Sub' Hunter
- Android Studio and our project – A very brief guided tour
- Locking the game to full-screen and landscape orientation
- Deploying the game so far
- Summary
- 2. Java: First Contact
- 3. Variables, Operators and Expressions
- 4. Structuring Code with Java Methods
- 5. The Android Canvas Class – Drawing to the Screen
- 6. Repeating Blocks of Code with Loops
- 7. Making Decisions with Java If, Else and Switch
- 8. Object-Oriented Programming
- Basic Object-Oriented Programming
- Looking at the code for a class
- Basic classes mini-app
- Remember that encapsulation thing?
- Encapsulation and static methods mini-app
- OOP and inheritance
- Inheritance mini-app
- Polymorphism
- Starting the Pong game
- Summary
- 9. The Game Engine, Threads, and The Game Loop
- Coding the PongActivity class
- Coding the PongGame class
- Coding the PongGame class
- The game loop
- Threads
- Implementing the game loop with a thread
- Implementing Runnable and providing the run method
- Coding the thread
- Starting and stopping the thread
- Activity lifecycle
- A simplified explanation of the Android lifecycle
- Lifecycle phases: What we need to know
- Lifecycle phases: What we need to do
- Using the Activity lifecycle to start and stop the thread
- Coding the run method
- Running the game
- Summary
- 10. Coding the Bat and Ball
- 11. Collisions, Sound Effects and Supporting Different Versions of Android
- 12. Handling Lots of Data with Arrays
- 13. Bitmap Graphics and Measuring Time
- 14. The Stack, the Heap, and the Garbage Collector
- 15. Android Localization -Hola!
- 16. Collections, Generics and Enumerations
- 17. Manipulating Bitmaps and Coding the Snake class
- 18. Introduction to Design Patterns and much more!
- Introducing the Scrolling Shooter project
- Game programming patterns and the structure of the Scrolling Shooter project
- Starting the project
- Controlling the game with a GameState class
- Giving partial access to a class using an interface
- Building a sound engine
- Testing the game so far
- Building a HUD class to display control buttons and text
- Building a Renderer class to handle the drawing
- Using the HUD and Renderer classes
- Running the game
- Summary
- 19. Listening with the Observer Pattern, Multitouch and Building a Particle System
- 20. More Patterns, a Scrolling Background and Building the Player's ship
- Meet the game objects
- The Entity-Component pattern
- The Simple Factory pattern
- Summary so far
- The object specifications
- Coding the component Interfaces
- Coding the player's and the background's empty component classes
- Every GameObject has a transform
- Every object is a GameObject
- Completing the player's and the background's components
- Building the GameObjectFactory
- Coding the Level class
- Putting everything together
- Running the game
- Summary
- 21. Completing the Scrolling Shooter Game
- 22. Exploring More Patterns and Planning the Platformer Project
- Platform Game: Bob Was in A Hurry
- How we will build the platformer
- Getting started with Bob was in a hurry
- Specifying all the game objects with GameObjectSpec classes
- GameObjectSpec
- BackgroundCitySpec
- BackgroundMountainSpec
- BackgroundUndergroundSpec
- BrickTileSpec
- CartTileSpec
- CoalTileSpec
- CollectibleObjectSpec
- ConcreteTileSpec
- DeadTreeTileSpec
- FireTileSpec
- GrassTileSpec
- LamppostTileSpec
- MoveablePlatformSpec
- ObjectiveTileSpec
- PlayerSpec
- ScorchedTileSpec
- SnowTileSpec
- SnowyTreeTileSpec
- StalactiteTileSpec
- StalagmiteTileSpec
- StonePileTileSpec
- Summary of component classes
- Coding the component interfaces
- Coding the other interfaces
- Summary
- 23. The Singleton Pattern, Java HashMap, Storing Bitmaps Efficiently and Designing Levels
- The Singleton pattern
- More Java Collections – Meet Java Hashmap
- The memory problem and the BitmapStore
- Coding the basic transform
- Coding the inanimate and decorative components
- Create the levels
- Coding a stripped down GameObjectFactory
- Coding a slightly commented-out game object
- Coding the GameState
- Code the SoundEngine
- Coding the physics engine (without collision)
- Coding a Renderer
- Coding the camera
- Coding the Hud
- Coding the UIController class
- Code the Activity
- Code the GameEngine
- Coding the LevelManager class
- Running the game
- Summary
- 24. Sprite-sheet animations, Controllable Player and Parallax Scrolling Backgrounds
- 25. Intelligent Platforms and Advanced Collision Detection
- 26. What next?
- Index
As a graphical means for explaining the Android coordinate drawing system, I will use a cute spaceship graphic. We will not suddenly be adding spaceships to Sub' Hunter but we will use the graphics that follow in the fifth project starting in Chapter 18, Introduction to Design Patterns and much more!.
As we will see, drawing a Bitmap is trivial. But the coordinate system that we use to draw our graphics onto needs a brief explanation.
When we draw a Bitmap object to the screen we pass in the coordinates we want to draw the object at. The available coordinates of a given Android device depend upon the resolution of its screen.
For example, the Google Pixel phone has a screen resolution of 1920 pixels (across) by 1080 pixels (down) when held in landscape view.
The numbering system of these coordinates starts in the top left-hand corner at 0,0 and proceeds down and to the right until the bottom right corner is pixel 1919, 1079. The apparent 1-pixel disparity between 1920/ 1919 and 1080/ 1079 is because the numbering starts at 0.
So, when we draw a Bitmap or any other drawable to the screen (like Canvas circles and rectangles), we must specify an x, y coordinate.
Furthermore, a Bitmap (or Canvas shape) is of course comprised of many pixels. So which pixel of a given Bitmap is drawn at the x, y screen coordinate that we will be specifying?
The answer is the top left pixel of the Bitmap object. Look at the next image which should clarify the screen coordinates using the Google Pixel phone as an example.
So, let's just bare that in mind for now and get on with drawing our grid to the screen.
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