Source Code
Thu, 04/03/2008 - 02:02 — tliebeck
The following is the source code of the NumberGuessApp.java file, which contains the application and component code used to create the Guess-A-Number application. This source code is also available in the Echo3 download in the directory: NextApp_Echo3 / SourceCode / src / server-java-examples / numberguess.
package numberguess;
import nextapp.echo.app.ApplicationInstance;
import nextapp.echo.app.Button;
import nextapp.echo.app.Color;
import nextapp.echo.app.ContentPane;
import nextapp.echo.app.Extent;
import nextapp.echo.app.Insets;
import nextapp.echo.app.Label;
import nextapp.echo.app.ResourceImageReference;
import nextapp.echo.app.Column;
import nextapp.echo.app.TextField;
import nextapp.echo.app.Window;
import nextapp.echo.app.event.ActionEvent;
import nextapp.echo.app.event.ActionListener;
import nextapp.echo.app.layout.ColumnLayoutData;
/**
* Guess-a-number Tutorial Application.
*/
public class NumberGuessApp extends ApplicationInstance {
private Window window;
/**
* Displays a congratulatory message to the user when s/he has guessed
* the correct number.
*
* @param numberOfTries the number of tries it took the user to guess the
* correct answer.
*/
void congratulate(int numberOfTries) {
window.setContent(new CongratulationsPane(numberOfTries));
}
/**
* @see nextapp.echo.app.ApplicationInstance#init()
*/
public Window init() {
window = new Window();
window.setTitle("Echo Guess-A-Number");
startNewGame();
return window;
}
/**
* Starts a new game:
* Sets content of Window to a new GamePane.
*/
void startNewGame() {
// Set the content to be a new GamePane, so the
window.setContent(new GamePane());
}
}
/**
* A ContentPane which generates a random number and provides the
* user opportunities to guess it.
*/
class GamePane extends ContentPane
implements ActionListener {
/** Randomly generated number between 1 and 100 inclusive. */
private int randomNumber = ((int) Math.floor(Math.random() * 100)) + 1;
/** The current lowest sensible guess, based on previous guesses. */
private int lowerBound = 1;
/** The current highest sensible guess, based on previous guesses. */
private int upperBound = 100;
/** The number of guesses made in the current game. */
private int numberOfTries = 0;
/** TextField into which guesses are entered. */
private TextField guessEntryField;
/**
* Label displaying the current "status". Initially blank,
* this label will inform the user whether his/her last guess was too
* high, too low, or simply invalid.
*/
private Label statusLabel = new Label();
/**
* Label indicating the total number of guesses made so far.
*/
private Label countLabel = new Label("You have made no guesses.");
/**
* Label prompting the user to enter a new guess. The text of
* this label will change as the user makes guesses to reflect the updated
* "sensible" range of possible guesses.
*/
private Label promptLabel = new Label(
"Guess a number between 1 and 100: ");
/**
* Creates a new GamePane.
*/
GamePane() {
super();
Column layoutColumn = new Column();
layoutColumn.setInsets(new Insets(30));
layoutColumn.setCellSpacing(new Extent(10));
add(layoutColumn);
layoutColumn.add(new Label(
new ResourceImageReference("/numberguess/TitleBanner.png")));
layoutColumn.add(statusLabel);
layoutColumn.add(countLabel);
layoutColumn.add(promptLabel);
guessEntryField = new TextField();
guessEntryField.setForeground(Color.WHITE);
guessEntryField.setBackground(Color.BLUE);
ColumnLayoutData columnLayoutData = new ColumnLayoutData();
columnLayoutData.setInsets(new Insets(20, 0));
guessEntryField.setLayoutData(columnLayoutData);
guessEntryField.setActionCommand("submit guess");
guessEntryField.addActionListener(this);
layoutColumn.add(guessEntryField);
Button submitButton = new Button("Submit Your Guess");
submitButton.setActionCommand("submit guess");
submitButton.setForeground(Color.BLACK);
submitButton.setBackground(Color.GREEN);
submitButton.setWidth(new Extent(200));
submitButton.addActionListener(this);
layoutColumn.add(submitButton);
Button newGameButton = new Button("Start a New Game");
newGameButton.setActionCommand("new game");
newGameButton.setForeground(Color.WHITE);
newGameButton.setBackground(Color.RED);
newGameButton.setWidth(new Extent(200));
newGameButton.addActionListener(this);
layoutColumn.add(newGameButton);
}
/**
* @see nextapp.echo.app.event.ActionListener#actionPerformed(
* nextapp.echo.app.event.ActionEvent)
*/
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("new game")) {
((NumberGuessApp) ApplicationInstance.getActive()).startNewGame();
} else if (e.getActionCommand().equals("submit guess")) {
processGuess();
}
}
/**
* Processes a user's guess.
*/
private void processGuess() {
int guess;
try {
guess = Integer.parseInt(guessEntryField.getDocument().getText());
} catch (NumberFormatException ex) {
statusLabel.setText("Your guess was not valid.");
return;
}
++numberOfTries;
if (guess == randomNumber) {
((NumberGuessApp) ApplicationInstance.getActive())
.congratulate(numberOfTries);
return;
}
if (guess < 1 || guess > 100) {
statusLabel.setText("Your guess, " + guess
+ " was not between 1 and 100.");
} else if (guess < randomNumber) {
if (guess >= lowerBound) {
lowerBound = guess + 1;
}
statusLabel.setText("Your guess, " + guess
+ " was too low. Try again:");
} else if (guess > randomNumber) {
statusLabel.setText("Your guess, " + guess
+ " was too high. Try again:");
if (guess <= upperBound) {
upperBound = guess - 1;
}
}
// Update number of tries label.
if (numberOfTries == 1) {
countLabel.setText("You have made 1 guess.");
} else {
countLabel.setText("You have made " + numberOfTries + " guesses.");
}
// Update prompt label to reflect the new sensible range of numbers.
promptLabel.setText("Guess a number between " + lowerBound + " and "
+ upperBound + ": ");
}
}
/**
* A ContentPane which presents a congratulatory message to the
* player when the correct number has been guessed.
*/
class CongratulationsPane extends ContentPane
implements ActionListener {
/**
* Creates a new CongratulationsPane.
*
* @param numberOfTries the number of tries it took the user to guess the
* correct answer.
*/
CongratulationsPane(int numberOfTries) {
Column layoutColumn = new Column();
layoutColumn.setInsets(new Insets(30));
layoutColumn.setCellSpacing(new Extent(30));
add(layoutColumn);
layoutColumn.add(new Label(new ResourceImageReference(
"/numberguess/CongratulationsBanner.png")));
layoutColumn.add(new Label("You got the correct answer in "
+ numberOfTries + (numberOfTries == 1 ? " try." : " tries.")));
Button button = new Button("Play Again");
button.setForeground(Color.WHITE);
button.setBackground(Color.RED);
button.setWidth(new Extent(200));
button.addActionListener(this);
layoutColumn.add(button);
}
/**
* @see nextapp.echo.app.event.ActionListener
* #actionPerformed(nextapp.echo.app.event.ActionEvent)
*/
public void actionPerformed(ActionEvent e) {
((NumberGuessApp) ApplicationInstance.getActive()).startNewGame();
}
}