🥇Tag yn Java - hoe in folweardich spultsje te ûntwikkeljen

"fyftjin" of "fyftjin" is in treflik foarbyld fan in ienfâldige logika spultsje dat is populêr oer de hiele wrâld. Om de puzel op te lossen, moatte jo de kwadraten mei nûmers yn folchoarder regelje, fan lyts oant grutste. It is net maklik, mar it is ynteressant.

Yn 'e tutorial fan hjoed sille wy jo sjen litte hoe't jo Fifteen ûntwikkelje yn Java 8 mei Eclipse. Om de UI te ûntwikkeljen sille wy de Swing API brûke.

Wy herinnerje: foar alle lêzers fan "Habr" - in koarting fan 10 roebel by it ynskriuwen fan in Skillbox-kursus mei de promoasjekoade "Habr".

Skillbox advisearret: Edukative online kursus "Berop Java Developer".

Game design

Op dit stadium moatte jo de eigenskippen definiearje:

Grutte - grutte fan it spielfjild;
nbTiles - oantal tags yn it fjild. nbTiles = grutte * grutte - 1;
Tegels is in tag dat in iendiminsjonale array is fan heule getallen. Elk fan 'e tags sil in unike wearde krije yn it berik [0, nbTiles]. Nul jout in leech fjouwerkant oan;
blankPos - posysje fan it lege plein.

Game logika

Wy moatte definiearje in reset metoade brûkt foar inisjalisearjen fan in nije spultsje posysje. Op dizze manier sette wy in wearde yn foar elk elemint fan 'e tags-array. No, dan pleatse wy blankPos yn 'e lêste posysje fan' e array.

Wy hawwe ek in shuffle-metoade nedich om de array fan tags te skodzjen. Wy befetsje de lege tag net yn it shufflingproses om it yn deselde posysje te litten.

Om't mar de helte fan 'e mooglike startposysjes fan' e puzel in oplossing hawwe, moatte jo it resultearjende shuffle-resultaat kontrolearje om te soargjen dat de hjoeddeistige yndieling sels oplosber is. Om dit te dwaan, definiearje wy de isSolvable metoade.

As in bepaalde tag wurdt foarôfgien troch in tag mei in hegere wearde, wurdt it beskôge as in omkearing. As it lege plak op it plak is, moat it oantal omkearingen even wêze om de puzel op te lossen. Dat wy telle it oantal inversions en jouwe wier as it oantal even is.

It is dan wichtich om de isSolved-metoade te definiearjen om te kontrolearjen as ús Game Of Fifteen-yndieling is oplost. Earst sjogge wy wêr't it lege plak is. As yn 'e earste posysje, dan is de hjoeddeistige ôfstimming nij, net earder besletten. Wy iterearje dan troch de tegels yn omkearde folchoarder, en as de wearde fan 'e tag oars is as de oerienkommende yndeks +1, jouwe wy falsk werom. Oars, oan 'e ein fan' e metoade is it tiid om werom te kommen wier omdat de puzel is al oplost.

In oare metoade dy't moat wurde definiearre is newGame. It is nedich om in nij eksimplaar fan it spul te meitsjen. Om dit te dwaan, sette wy it spylfjild werom, skodzje it dan en trochgean oant de spielposysje oplosber is.

Hjir is in foarbyldkoade mei de kaailogika fan tag:

private void newGame() {
  do {
    reset(); // reset in initial state
    shuffle(); // shuffle
  } while(!isSolvable()); // make it until grid be solvable
 
  gameOver = false;
}
 
private void reset() {
  for (int i = 0; i < tiles.length; i++) {
    tiles[i] = (i + 1) % tiles.length;
  }
 
  // we set blank cell at the last
  blankPos = tiles.length - 1;
}
 
private void shuffle() {
  // don't include the blank tile in the shuffle, leave in the solved position
  int n = nbTiles;
 
  while (n > 1) {
    int r = RANDOM.nextInt(n--);
    int tmp = tiles[r];
    tiles[r] = tiles[n];
    tiles[n] = tmp;
  }
}
 
// Only half permutations of the puzzle are solvable/
// Whenever a tile is preceded by a tile with higher value it counts
// as an inversion. In our case, with the blank tile in the solved position,
// the number of inversions must be even for the puzzle to be solvable
private boolean isSolvable() {
  int countInversions = 0;
 
  for (int i = 0; i < nbTiles; i++) {
    for (int j = 0; j < i; j++) {
      if (tiles[j] > tiles[i])
        countInversions++;
    }
  }
 
  return countInversions % 2 == 0;
}
 
private boolean isSolved() {
  if (tiles[tiles.length - 1] != 0) // if blank tile is not in the solved position ==> not solved
    return false;
 
  for (int i = nbTiles - 1; i >= 0; i--) {
    if (tiles[i] != i + 1)
      return false;
  }
 
  return true;
}

Uteinlik moatte jo de beweging fan 'e tags yn' e array programmearje. Dizze koade sil letter wurde neamd fia in weromrop om te reagearjen op beweging fan de rinnerke. Us spultsje sil meardere tegelbewegingen tagelyk stypje. Sa, neidat wy hawwe omset de yndrukte posysje op it skerm yn in tag, wy krije de posysje fan de lege tag en sykje nei in rjochting fan beweging te stypjen ferskate fan syn bewegingen tagelyk.

Hjir is in koade foarbyld:

// get position of the click
int ex = e.getX() - margin;
int ey = e.getY() - margin;
 
// click in the grid ?
if (ex < 0 || ex > gridSize  || ey < 0  || ey > gridSize)
  return;
 
// get position in the grid
int c1 = ex / tileSize;
int r1 = ey / tileSize;
 
// get position of the blank cell
int c2 = blankPos % size;
int r2 = blankPos / size;
 
// we convert in the 1D coord
int clickPos = r1 * size + c1;
 
int dir = 0;
 
// we search direction for multiple tile moves at once
if (c1 == c2  &&  Math.abs(r1 - r2) > 0)
  dir = (r1 - r2) > 0 ? size : -size;
else if (r1 == r2 && Math.abs(c1 - c2) > 0)
  dir = (c1 - c2) > 0 ? 1 : -1;
 
if (dir != 0) {
  // we move tiles in the direction
  do {
    int newBlankPos = blankPos + dir;
    tiles[blankPos] = tiles[newBlankPos];
    blankPos = newBlankPos;
  } while(blankPos != clickPos);
 
tiles[blankPos] = 0;

Wy ûntwikkelje UI mei Swing API

It is tiid om te wurkjen oan de ynterface. Earst nimme wy de Jpanel-klasse. Dan tekenje wy tags op it fjild - om de grutte fan elk te berekkenjen, sille wy de gegevens brûke dy't spesifisearre binne yn 'e spielkonstruktorparameter:

gridSize = (dim  -  2 * margin);
tileSize = gridSize / size;

Marzje is ek in parameter ynsteld yn it spultsje constructor.

No moatte wy de metoade drawGrid definiearje om it raster en spots op it skerm te tekenjen. Wy analysearje de array fan tags en konvertearje de koördinaten yn koördinaten fan brûkersynterface. Dan tekenje elk plak mei it oerienkommende nûmer yn it sintrum:

private void drawGrid(Graphics2D g) {
  for (int i = 0; i < tiles.length; i++) {
    // we convert 1D coords to 2D coords given the size of the 2D Array
    int r = i / size;
    int c = i % size;
    // we convert in coords on the UI
    int x = margin + c * tileSize;
    int y = margin + r * tileSize;
 
    // check special case for blank tile
    if(tiles[i] == 0) {
      if (gameOver) {
        g.setColor(FOREGROUND_COLOR);
        drawCenteredString(g, "u2713", x, y);
      }
 
      continue;
    }
 
    // for other tiles
    g.setColor(getForeground());
    g.fillRoundRect(x, y, tileSize, tileSize, 25, 25);
    g.setColor(Color.BLACK);
    g.drawRoundRect(x, y, tileSize, tileSize, 25, 25);
    g.setColor(Color.WHITE);
 
    drawCenteredString(g, String.valueOf(tiles[i]), x , y);
  }
}

As lêste, litte wy de metoade paintComponent oerskriuwe, dy't ôflaat fan 'e JPane-klasse. Wy brûke dan de metoade drawGrid, folge troch de metoade drawStartMessage om in berjocht wer te jaan dat ús freget te klikken om it spultsje te begjinnen:

private void drawStartMessage(Graphics2D g) {
  if (gameOver) {
    g.setFont(getFont().deriveFont(Font.BOLD, 18));
    g.setColor(FOREGROUND_COLOR);
    String s = "Click to start new game";
    g.drawString(s, (getWidth() - g.getFontMetrics().stringWidth(s)) / 2,
        getHeight() - margin);
  }
}
 
private void drawCenteredString(Graphics2D g, String s, int x, int y) {
  // center string s for the given tile (x,y)
  FontMetrics fm = g.getFontMetrics();
  int asc = fm.getAscent();
  int desc = fm.getDescent();
  g.drawString(s,  x + (tileSize - fm.stringWidth(s)) / 2,
      y + (asc + (tileSize - (asc + desc)) / 2));
}
 
@Override
protected void paintComponent(Graphics g) {
  super.paintComponent(g);
  Graphics2D g2D = (Graphics2D) g;
  g2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
  drawGrid(g2D);
  drawStartMessage(g2D);
}

Reagearje op brûkersaksjes yn 'e UI

Om it spultsje syn kursus te rinnen, is it nedich om brûkersaksjes te ferwurkjen yn 'e UI. Om dit te dwaan, foegje de ymplemintaasje fan MouseListener ta op Jpanel en de koade foar ferpleatse spots, al werjûn hjirboppe:

addMouseListener(new MouseAdapter() {
  @Override
  public void mousePressed(MouseEvent e) {
    // used to let users to interact on the grid by clicking
    // it's time to implement interaction with users to move tiles to solve the game !
    if (gameOver) {
      newGame();
    } else {
      // get position of the click
      int ex = e.getX() - margin;
      int ey = e.getY() - margin;
 
      // click in the grid ?
      if (ex < 0 || ex > gridSize  || ey < 0  || ey > gridSize)
        return;
 
      // get position in the grid
      int c1 = ex / tileSize;
      int r1 = ey / tileSize;
 
      // get position of the blank cell
      int c2 = blankPos % size;
      int r2 = blankPos / size;
 
      // we convert in the 1D coord
      int clickPos = r1 * size + c1;
 
      int dir = 0;
 
      // we search direction for multiple tile moves at once
      if (c1 == c2  &&  Math.abs(r1 - r2) > 0)
        dir = (r1 - r2) > 0 ? size : -size;
      else if (r1 == r2 && Math.abs(c1 - c2) > 0)
        dir = (c1 - c2) > 0 ? 1 : -1;
 
      if (dir != 0) {
        // we move tiles in the direction
        do {
          int newBlankPos = blankPos + dir;
          tiles[blankPos] = tiles[newBlankPos];
          blankPos = newBlankPos;
        } while(blankPos != clickPos);
 
        tiles[blankPos] = 0;
      }
 
      // we check if game is solved
      gameOver = isSolved();
    }
 
    // we repaint panel
    repaint();
  }
});

Wy pleatse de koade yn 'e konstruktor fan' e GameOfFifteen-klasse. Oan 'e ein neame wy de newGame-metoade om in nij spultsje te begjinnen.

Folsleine spultsje koade

De lêste stap foar it sjen fan it spultsje yn aksje is om alle koade-eleminten byinoar te setten. Hjir is wat der bart:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Random;
 
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
 
// We are going to create a Game of 15 Puzzle with Java 8 and Swing
// If you have some questions, feel free to read comments ;)
public class GameOfFifteen extends JPanel { // our grid will be drawn in a dedicated Panel
 
  // Size of our Game of Fifteen instance
  private int size;
  // Number of tiles
  private int nbTiles;
  // Grid UI Dimension
  private int dimension;
  // Foreground Color
  private static final Color FOREGROUND_COLOR = new Color(239, 83, 80); // we use arbitrary color
  // Random object to shuffle tiles
  private static final Random RANDOM = new Random();
  // Storing the tiles in a 1D Array of integers
  private int[] tiles;
  // Size of tile on UI
  private int tileSize;
  // Position of the blank tile
  private int blankPos;
  // Margin for the grid on the frame
  private int margin;
  // Grid UI Size
  private int gridSize;
  private boolean gameOver; // true if game over, false otherwise
 
  public GameOfFifteen(int size, int dim, int mar) {
    this.size = size;
    dimension = dim;
    margin = mar;
    
    // init tiles
    nbTiles = size * size - 1; // -1 because we don't count blank tile
    tiles = new int[size * size];
    
    // calculate grid size and tile size
    gridSize = (dim - 2 * margin);
    tileSize = gridSize / size;
    
    setPreferredSize(new Dimension(dimension, dimension + margin));
    setBackground(Color.WHITE);
    setForeground(FOREGROUND_COLOR);
    setFont(new Font("SansSerif", Font.BOLD, 60));
    
    gameOver = true;
    
    addMouseListener(new MouseAdapter() {
      @Override
      public void mousePressed(MouseEvent e) {
        // used to let users to interact on the grid by clicking
        // it's time to implement interaction with users to move tiles to solve the game !
        if (gameOver) {
          newGame();
        } else {
          // get position of the click
          int ex = e.getX() - margin;
          int ey = e.getY() - margin;
          
          // click in the grid ?
          if (ex < 0 || ex > gridSize  || ey < 0  || ey > gridSize)
            return;
          
          // get position in the grid
          int c1 = ex / tileSize;
          int r1 = ey / tileSize;
          
          // get position of the blank cell
          int c2 = blankPos % size;
          int r2 = blankPos / size;
          
          // we convert in the 1D coord
          int clickPos = r1 * size + c1;
          
          int dir = 0;
          
          // we search direction for multiple tile moves at once
          if (c1 == c2  &&  Math.abs(r1 - r2) > 0)
            dir = (r1 - r2) > 0 ? size : -size;
          else if (r1 == r2 && Math.abs(c1 - c2) > 0)
            dir = (c1 - c2) > 0 ? 1 : -1;
            
          if (dir != 0) {
            // we move tiles in the direction
            do {
              int newBlankPos = blankPos + dir;
              tiles[blankPos] = tiles[newBlankPos];
              blankPos = newBlankPos;
            } while(blankPos != clickPos);
            
            tiles[blankPos] = 0;
          }
          
          // we check if game is solved
          gameOver = isSolved();
        }
        
        // we repaint panel
        repaint();
      }
    });
    
    newGame();
  }
 
  private void newGame() {
    do {
      reset(); // reset in intial state
      shuffle(); // shuffle
    } while(!isSolvable()); // make it until grid be solvable
    
    gameOver = false;
  }
 
  private void reset() {
    for (int i = 0; i < tiles.length; i++) {
      tiles[i] = (i + 1) % tiles.length;
    }
    
    // we set blank cell at the last
    blankPos = tiles.length - 1;
  }
 
  private void shuffle() {
    // don't include the blank tile in the shuffle, leave in the solved position
    int n = nbTiles;
    
    while (n > 1) {
      int r = RANDOM.nextInt(n--);
      int tmp = tiles[r];
      tiles[r] = tiles[n];
      tiles[n] = tmp;
    }
  }
 
  // Only half permutations of the puzzle are solvable.
  // Whenever a tile is preceded by a tile with higher value it counts
  // as an inversion. In our case, with the blank tile in the solved position,
  // the number of inversions must be even for the puzzle to be solvable
  private boolean isSolvable() {
    int countInversions = 0;
    
    for (int i = 0; i < nbTiles; i++) {
      for (int j = 0; j < i; j++) {
        if (tiles[j] > tiles[i])
          countInversions++;
      }
    }
    
    return countInversions % 2 == 0;
  }
 
  private boolean isSolved() {
    if (tiles[tiles.length - 1] != 0) // if blank tile is not in the solved position ==> not solved
      return false;
    
    for (int i = nbTiles - 1; i >= 0; i--) {
      if (tiles[i] != i + 1)
        return false;      
    }
    
    return true;
  }
 
  private void drawGrid(Graphics2D g) {
    for (int i = 0; i < tiles.length; i++) {
      // we convert 1D coords to 2D coords given the size of the 2D Array
      int r = i / size;
      int c = i % size;
      // we convert in coords on the UI
      int x = margin + c * tileSize;
      int y = margin + r * tileSize;
      
      // check special case for blank tile
      if(tiles[i] == 0) {
        if (gameOver) {
          g.setColor(FOREGROUND_COLOR);
          drawCenteredString(g, "u2713", x, y);
        }
        
        continue;
      }
      
      // for other tiles
      g.setColor(getForeground());
      g.fillRoundRect(x, y, tileSize, tileSize, 25, 25);
      g.setColor(Color.BLACK);
      g.drawRoundRect(x, y, tileSize, tileSize, 25, 25);
      g.setColor(Color.WHITE);
      
      drawCenteredString(g, String.valueOf(tiles[i]), x , y);
    }
  }
 
  private void drawStartMessage(Graphics2D g) {
    if (gameOver) {
      g.setFont(getFont().deriveFont(Font.BOLD, 18));
      g.setColor(FOREGROUND_COLOR);
      String s = "Click to start new game";
      g.drawString(s, (getWidth() - g.getFontMetrics().stringWidth(s)) / 2,
          getHeight() - margin);
    }
  }
 
  private void drawCenteredString(Graphics2D g, String s, int x, int y) {
    // center string s for the given tile (x,y)
    FontMetrics fm = g.getFontMetrics();
    int asc = fm.getAscent();
    int desc = fm.getDescent();
    g.drawString(s,  x + (tileSize - fm.stringWidth(s)) / 2,
        y + (asc + (tileSize - (asc + desc)) / 2));
  }
 
  @Override
  protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2D = (Graphics2D) g;
    g2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    drawGrid(g2D);
    drawStartMessage(g2D);
  }
 
  public static void main(String[] args) {
    SwingUtilities.invokeLater(() -> {
      JFrame frame = new JFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setTitle("Game of Fifteen");
      frame.setResizable(false);
      frame.add(new GameOfFifteen(4, 550, 30), BorderLayout.CENTER);
      frame.pack();
      // center on the screen
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
    });
  }
 
 
}

As lêste, litte wy spylje!

It is tiid om it spultsje te starten en it yn aksje te testen. It fjild moat der sa útsjen:

Litte wy besykje de puzel op te lossen. As alles goed gie, krije wy dit:

Da's alles. Hasto mear ferwachte? 🙂

Skillbox advisearret:

Praktyske kursus "Mobiele ûntwikkelder PRO".

Oanfrege online kursus "Python Data Analyst".

Twa jier praktyske kursus "Ik bin in PRO webûntwikkelder".

Boarne: www.habr.com

"Tag" yn Java - hoe te ûntwikkeljen in folweardich spultsje