Foundation Game Design with ActionScript 3.0, Second Edition (48 page)

The structure of this program is identical to the other programs you've looked at in this book so far. The only anomaly to point out is that the constructor method has delegated its work of creating the button to the
makeButton
method.

This is the same technique you used to modularize the code in the constructor method of the number guessing game.

I'm now going to give you the delicate job of merging the code from the Buttons.as file with the NumberGuessingGame.as file. The number guessing game is going to end up with a button that you can click. Clicking it should have the same effect as pressing the Enter key.

Before you panic, know that you don't need to learn any new code or techniques. As long as you understand how to add code to a program—where to put it and what effect it has—you'll be able to do this. This will be good practice to make sure you've properly absorbed all the concepts covered in the past four chapters. When you're done, you'll end up with a game that looks a bit like
Figure 4-34
.

Figure 4-34.
The number guessing game with an interactive button

Here are some things you'll need to do:

1. Copy your images folder from the Buttons project folder to the NumberGuessingGame folder.
   
2. Keep all the code that makes and sets up the button in its own
   makeButton
method. You can then call that method in the number guessing game's constructor method, like this:
   
   public function NumberGuessingGame()
{
  setupTextfields();
  
makeButton();
  startGame();
}

3. Add the button event listeners to the
   startGame
method. This lets you easily reinitialize the game if you want to add a Play again button in later steps. Here's where the button event listeners should be added:
   
   public function startGame():void
{
  //Initialize variables
  startMessage = "I am thinking of a number between 0 and 99";
  mysteryNumber = Math.floor(Math.random() * 100);
  //Initialize text fields
  output.text = startMessage
  input.text = "";
  guessesRemaining = 10;
  guessesMade = 0;
  gameStatus = "";
  gameWon = false;
  //Trace the mystery number
  trace("The mystery number: " + mysteryNumber);
  //Add an event listener for key presses
  stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressHandler);
  //Add the button event listeners
  button.addEventListener(MouseEvent.ROLL_OVER, overHandler);
  button.addEventListener(MouseEvent.MOUSE_DOWN, downHandler);
  button.addEventListener(MouseEvent.ROLL_OUT, resetHandler);
  button.addEventListener(MouseEvent.CLICK, clickHandler);
}

4. When the player clicks the button, the game should read the number that's in the input field. You already have a method called
   playGame
that analyzes the input. All you need to do is connect it to the button's CLICK event, like this:
   
   public function clickHandler(event:MouseEvent):void
{
  buttonUpImage.visible = true;
  buttonDownImage.visible = false;
  buttonOverImage.visible = false;
  
playGame();
}


   Because you've modularized all your code into methods, it's very easy to connect the button to the existing
   playGame
method. You don't need to write any new code for your game at all. The Enter key and the button call the same method when they're activated.
   

When you've got the button working nicely in your game, you may want to disable it when the game is over, the same way you disable the Enter key. To do that, add the following code in bold text to the end of the
endGame
method:

This new code removes all the listeners so the button has no more functionality. It also makes the button transparent as a visual cue that the button doesn't work anymore. Finally, it sets the button's
mouseEnabled
property to false, which prevents it from being sensitive to the mouse.
Figure 4-35
shows what you'll see.

Figure 4-35.
Dim and disable the button at the end of the game.

This is a lot of new code for you to write! In case you have any doubts as to how it should look, you'll find the entire project, up to this point, in the folder NumberGuessingGameWithButton, in the chapter's source files. Here's a complete listing of all the code for the game so far: