Criando o jogo Labirinto para dispositivos móveis
Veja nesta dica como desenvolver o jogo Labirinto para aparelhos J2ME.
import java.util.Random;
import java.util.Vector;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class Maze extends MIDlet implements CommandListener {
private MazeCanvas myCanvas;
private SelectScreen mySelectScreen;
private Command myExitCommand = new Command("Exit", Command.EXIT, 99);
private Command myNewCommand = new Command("New Maze", Command.SCREEN, 1);
private Command myAlertDoneCommand = new Command("Done", Command.EXIT, 1);
private Command myPrefsCommand
= new Command("Size Preferences", Command.SCREEN, 1);
public Maze() {
try { myCanvas = new MazeCanvas(Display.getDisplay(this));
myCanvas.addCommand(myExitCommand);
myCanvas.addCommand(myNewCommand);
myCanvas.addCommand(myPrefsCommand);
myCanvas.setCommandListener(this);
} catch(Exception e) {
Alert errorAlert = new Alert("error",
e.getMessage(), null, AlertType.ERROR);
errorAlert.setCommandListener(this);
errorAlert.setTimeout(Alert.FOREVER);
errorAlert.addCommand(myAlertDoneCommand);
Display.getDisplay(this).setCurrent(errorAlert);
}
}
public void startApp() throws MIDletStateChangeException {
if(myCanvas != null) {
myCanvas.start();
}
}
public void destroyApp(boolean unconditional)
throws MIDletStateChangeException {
myCanvas = null;
System.gc();
}
public void pauseApp() {
}
public void commandAction(Command c, Displayable s) {
if(c == myNewCommand) {
myCanvas.newMaze();
} else if(c == myAlertDoneCommand) {
try {
destroyApp(false);
notifyDestroyed();
} catch (MIDletStateChangeException ex) {
}
} else if(c == myPrefsCommand) {
if(mySelectScreen == null) {
mySelectScreen = new SelectScreen(myCanvas);
}
Display.getDisplay(this).setCurrent(mySelectScreen);
} else if(c == myExitCommand) {
try {
destroyApp(false);
notifyDestroyed();
} catch (MIDletStateChangeException ex) {
}
}
}
}
class MazeCanvas extends javax.microedition.lcdui.Canvas {
public static final int BLACK = 0;
public static final int WHITE = 0xffffff;
private Display myDisplay;
private Grid myGrid;
private boolean myGameOver = false;
private int mySquareSize;
private int myMaxSquareSize;
private int myMinSquareSize;
private int myStartX = 0;
private int myStartY = 0;
private int myGridHeight;
private int myGridWidth;
private int myMaxGridWidth;
private int myMinGridWidth;
private int myOldX = 1;
private int myOldY = 1;
private int myPlayerX = 1;
private int myPlayerY = 1;
int setColWidth(int colWidth) {
if(colWidth < 2) {
mySquareSize = 2;
} else {
mySquareSize = colWidth;
}
myGridWidth = getWidth() / mySquareSize;
if(myGridWidth % 2 == 0) {
myGridWidth -= 1;
}
myGridHeight = getHeight() / mySquareSize;
if(myGridHeight % 2 == 0) {
myGridHeight -= 1;
}
myGrid = null;
return(myGridWidth);
}
int getMinColWidth() {
return(myMinSquareSize);
}
int getMaxColWidth() {
return(myMaxSquareSize);
}
int getMaxNumCols() {
return(myMaxGridWidth);
}
int getColWidth() {
return(mySquareSize);
}
int getNumCols() {
return(myGridWidth);
}
public MazeCanvas(Display d) throws Exception {
myDisplay = d;
int width = getWidth();
int height = getHeight();
mySquareSize = 5;
myMinSquareSize = 3;
myMaxGridWidth = width / myMinSquareSize;
if(myMaxGridWidth % 2 == 0) {
myMaxGridWidth -= 1;
}
myGridWidth = width / mySquareSize;
if(myGridWidth % 2 == 0) {
myGridWidth -= 1;
}
myGridHeight = height / mySquareSize;
if(myGridHeight % 2 == 0) {
myGridHeight -= 1;
}
myMinGridWidth = 15;
myMaxSquareSize = width / myMinGridWidth;
if(myMaxSquareSize > height / myMinGridWidth) {
myMaxSquareSize = height / myMinGridWidth;
}
if(myMaxSquareSize < mySquareSize) {
throw(new Exception("Display too small"));
}
}
void start() {
myDisplay.setCurrent(this);
repaint();
}
void newMaze() {
myGameOver = false;
myGrid = null;
myPlayerX = 1;
myPlayerY = 1;
myOldX = 1;
myOldY = 1;
myDisplay.setCurrent(this);
repaint();
}
protected void paint(Graphics g) {
if(myGrid == null) {
int width = getWidth();
int height = getHeight();
myGrid = new Grid(myGridWidth, myGridHeight);
for(int i = 0; i < myGridWidth; i++) {
for(int j = 0; j < myGridHeight; j++) {
if(myGrid.mySquares[i][j] == 0) {
g.setColor(BLACK);
} else {
g.setColor(WHITE);
}
g.fillRect(myStartX + (i*mySquareSize),
myStartY + (j*mySquareSize),
mySquareSize, mySquareSize);
}
}
g.setColor(BLACK);
g.fillRect(myStartX + ((myGridWidth-1) * mySquareSize),
myStartY, width, height);
g.setColor(WHITE);
g.fillRect(myStartX + ((myGridWidth-1) * mySquareSize),
myStartY + ((myGridHeight-2) * mySquareSize), width, height);
g.setColor(BLACK);
g.fillRect(myStartX,
myStartY + ((myGridHeight-1) * mySquareSize), width, height);
}
g.setColor(255, 0, 0);
g.fillRoundRect(myStartX + (mySquareSize)*myPlayerX,
myStartY + (mySquareSize)*myPlayerY,
mySquareSize, mySquareSize,
mySquareSize, mySquareSize);
if((myOldX != myPlayerX) || (myOldY != myPlayerY)) {
g.setColor(WHITE);
g.fillRect(myStartX + (mySquareSize)*myOldX,
myStartY + (mySquareSize)*myOldY,
mySquareSize, mySquareSize);}
if(myGameOver) {
int width = getWidth();
int height = getHeight();
Font font = g.getFont();
int fontHeight = font.getHeight();
int fontWidth = font.stringWidth("Maze Completed");
g.setColor(WHITE);
g.fillRect((width - fontWidth)/2, (height - fontHeight)/2,
fontWidth + 2, fontHeight);
g.setColor(255, 0, 0);
g.setFont(font);
g.drawString("Maze Completed", (width - fontWidth)/2,
(height - fontHeight)/2,
g.TOP|g.LEFT);
}
}
public void keyPressed(int keyCode) {
if(! myGameOver) {
int action = getGameAction(keyCode);
switch (action) {
case LEFT:
if((myGrid.mySquares[myPlayerX-1][myPlayerY] == 1) &&
(myPlayerX != 1)) {
myOldX = myPlayerX;
myOldY = myPlayerY;
myPlayerX -= 2;
repaint();
}
break;
case RIGHT:
if(myGrid.mySquares[myPlayerX+1][myPlayerY] == 1) {
myOldX = myPlayerX;
myOldY = myPlayerY;
myPlayerX += 2;
repaint();
} else if((myPlayerX == myGrid.mySquares.length - 2) &&
(myPlayerY == myGrid.mySquares[0].length - 2)) {
myOldX = myPlayerX;
myOldY = myPlayerY;
myPlayerX += 2;
myGameOver = true;
repaint();
}
break;
case UP:
if(myGrid.mySquares[myPlayerX][myPlayerY-1] == 1) {
myOldX = myPlayerX;
myOldY = myPlayerY;
myPlayerY -= 2;
repaint();
}
break;
case DOWN:
if(myGrid.mySquares[myPlayerX][myPlayerY+1] == 1) {
myOldX = myPlayerX;
myOldY = myPlayerY;
myPlayerY += 2;
repaint();
}
break;
}
}
}
}
class SelectScreen extends Form
implements ItemStateListener, CommandListener {
private Command myExitCommand = new Command("Done", Command.EXIT, 1);
private Gauge myWidthGauge;
private Gauge myColumnsGauge;
private MazeCanvas myCanvas;
public SelectScreen(MazeCanvas canvas) {
super("Size Preferences");
addCommand(myExitCommand);
setCommandListener(this);
myCanvas = canvas;
setItemStateListener(this);
myWidthGauge = new Gauge("Column Width", true,
myCanvas.getMaxColWidth(),
myCanvas.getColWidth());
myColumnsGauge = new Gauge("Number of Columns", false,
myCanvas.getMaxNumCols(),
myCanvas.getNumCols());
append(myWidthGauge);
append(myColumnsGauge);
}
public void itemStateChanged(Item item) {
if(item == myWidthGauge) {
int val = myWidthGauge.getValue();
if(val < myCanvas.getMinColWidth()) {
myWidthGauge.setValue(myCanvas.getMinColWidth());
} else {
int numCols = myCanvas.setColWidth(val);
myColumnsGauge.setValue(numCols);
}
}
}
public void commandAction(Command c, Displayable s) {
if(c == myExitCommand) {
myCanvas.newMaze();
}
}
}
class Grid {
private Random myRandom = new Random();
int[][] mySquares;
public Grid(int width, int height) {
mySquares = new int[width][height];
for(int i = 1; i < width - 1; i++) {
for(int j = 1; j < height - 1; j++) {
if((i % 2 == 1) || (j % 2 == 1)) {
mySquares[i][j] = 1;
}
}
}
mySquares[0][1] = 1;
createMaze();
}
private void createMaze() {
// create an initial framework of black squares.
for(int i = 1; i < mySquares.length - 1; i++) {
for(int j = 1; j < mySquares[i].length - 1; j++) {
if((i + j) % 2 == 1) {
mySquares[i][j] = 0;
}
}
}
for(int i = 1; i < mySquares.length - 1; i+=2) {
for(int j = 1; j < mySquares[i].length - 1; j+=2) {
mySquares[i][j] = 3;
}
}
Vector possibleSquares = new Vector(mySquares.length
* mySquares[0].length);
int[] startSquare = new int[2];
startSquare[0] = getRandomInt(mySquares.length / 2)*2 + 1;
startSquare[1] = getRandomInt(mySquares[0].length / 2)*2 + 1;
mySquares[startSquare[0]][startSquare[1]] = 2;
possibleSquares.addElement(startSquare);
while(possibleSquares.size() > 0) {
int chosenIndex = getRandomInt(possibleSquares.size());
int[] chosenSquare = (int[])possibleSquares.elementAt(chosenIndex);
mySquares[chosenSquare[0]][chosenSquare[1]] = 1;
possibleSquares.removeElementAt(chosenIndex);
link(chosenSquare, possibleSquares);
}
possibleSquares = null;
System.gc();
}
private void link(int[] chosenSquare, Vector possibleSquares) {
int linkCount = 0;
int i = chosenSquare[0];
int j = chosenSquare[1];
int[] links = new int[8];
if(i >= 3) {
if(mySquares[i - 2][j] == 1) {
links[2*linkCount] = i - 1;
links[2*linkCount + 1] = j;
linkCount++;
} else if(mySquares[i - 2][j] == 3) {
mySquares[i - 2][j] = 2;
int[] newSquare = new int[2];
newSquare[0] = i - 2;
newSquare[1] = j;
possibleSquares.addElement(newSquare);
}
}
if(j + 3 <= mySquares[i].length) {
if(mySquares[i][j + 2] == 3) {
mySquares[i][j + 2] = 2;
int[] newSquare = new int[2];
newSquare[0] = i;
newSquare[1] = j + 2;
possibleSquares.addElement(newSquare);
} else if(mySquares[i][j + 2] == 1) {
links[2*linkCount] = i;
links[2*linkCount + 1] = j + 1;
linkCount++;
}
}
if(j >= 3) {
if(mySquares[i][j - 2] == 3) {
mySquares[i][j - 2] = 2;
int[] newSquare = new int[2];
newSquare[0] = i;
newSquare[1] = j - 2;
possibleSquares.addElement(newSquare);
} else if(mySquares[i][j - 2] == 1) {
links[2*linkCount] = i;
links[2*linkCount + 1] = j - 1;
linkCount++;
}
}
if(i + 3 <= mySquares.length) {
if(mySquares[i + 2][j] == 3) {
mySquares[i + 2][j] = 2;
int[] newSquare = new int[2];
newSquare[0] = i + 2;
newSquare[1] = j;
possibleSquares.addElement(newSquare);
} else if(mySquares[i + 2][j] == 1) {
links[2*linkCount] = i + 1;
links[2*linkCount + 1] = j;
linkCount++;
}
}
if(linkCount > 0) {
int linkChoice = getRandomInt(linkCount);
int linkX = links[2*linkChoice]; int linkY = links[2*linkChoice + 1];
mySquares[linkX][linkY] = 1;
int[] removeSquare = new int[2];
removeSquare[0] = linkX;
removeSquare[1] = linkY;
possibleSquares.removeElement(removeSquare);
}
}
public int getRandomInt(int upper) {
int retVal = myRandom.nextInt() % upper;
if(retVal < 0) {
retVal += upper;
}
return(retVal);
}
}
