java - 代码在我们没有要求的情况下运行多次

Question

我们正在尝试使用二维数组用图 block 绘制棋盘，但每次运行代码时，它都会经过 PaintComponent 2 到 3 次(每次都不同)，而我们只尝试遍历一次。

这是我们的代码

Board.java:

public class Board extends JComponent {

    public Board() {

    }

    public static String[] gameElements = new String[100];


    private String[][] map = new String[10][10];
    private int positionX = 50;
    private int positionY = 50;
    private String currentLevel = "1";

    public String[][] getMap(){
        return map;
    }

    public void setMap(String[][] map){
        this.map = map;
    }

    @Override
    public void paintComponent(Graphics g) {
        loadLevel();
        int i = 0;
        int positionX = 50;
        int positionY = 50;
        for (int y = 0; y < map.length; y++) {
            for (int x = 0; x < map.length; x++) {
                new Tile(x, y).paintComponent(g);
                map[y][x] = gameElements[i];
                g.drawString(gameElements[i], positionY, positionX);
                positionY += 50;
                System.out.print("[" + map[y][x] + "]");
                i++;
            }
            positionY = 50;
            positionX += 50;
            System.out.println();

        }
    }

    public void readTextFile(String fileName) {
        try {
            FileReader fileReader = new FileReader(fileName + ".txt");
            BufferedReader buffer = new BufferedReader(fileReader);
            String splitBy = ",";
            String line = buffer.readLine();

            for (int i = 0; i < gameElements.length; i++) {
                gameElements = line.split(splitBy);
            }

        } catch (FileNotFoundException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public void loadLevel() {
        readTextFile(currentLevel);
    }

    public static void main(String[] args) {

        JFrame frame = new JFrame();
        frame.setSize(600, 600);
        frame.setTitle("SleutelBarricade");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JComponent chart = new Board();
        frame.add(chart);

        frame.setVisible(true);


    }
}

Tile.java:

public class Tile extends Board {

    public Tile() {

    }

    final private static int CELL_WIDTH = 50;
    final private static int CELL_HEIGHT = 50;

    final private static int BOARD_X_OFFSET = 25;
    final private static int BOARD_Y_OFFSET = 25;

    private int x;
    private int y;

    private int getScreenX(int x, int y) {
        return BOARD_X_OFFSET + x * CELL_WIDTH;
    }

    private int getScreenY(int x, int y) {
        return BOARD_Y_OFFSET + y * CELL_HEIGHT;
    }

    public Tile(int x, int y) {
        this.x = x;
        this.y = y;
    }

    @Override
    public void paintComponent(Graphics g) {
        g.setColor(Color.BLACK);
        g.drawRect(
                getScreenX(x, y),
                getScreenY(x, y),
                CELL_WIDTH,
                CELL_HEIGHT);
    }

}

结果:

"C:\Program Files\Java\jdk1.8.0_77\bin\java" -Didea.launcher.port=7537 "-Didea.launcher.bin.path=C:\Program Files (x86)\JetBrains\IntelliJ IDEA 2016.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_77\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_77\jre\lib\rt.jar;C:\Users\Darryl Soerdjpal\Desktop\TestBoard\out\production\TestBoard;C:\Program Files (x86)\JetBrains\IntelliJ IDEA 2016.1\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain Main.GameBoard.Board
[E][W][B][E][E][E][E][B][B][B]
[E][E][E][E][K][K][E][B][B][B]
[E][E][B][E][E][E][E][B][B][K]
[E][W][B][E][E][E][E][B][B][B]
[E][W][B][B][W][W][W][B][B][B]
[E][B][B][E][E][E][W][B][B][E]
[E][W][B][W][W][B][W][W][E][E]
[E][W][B][B][B][B][E][E][E][E]
[K][W][B][B][E][E][E][W][E][E]
[E][W][B][B][E][E][E][W][E][F]
[E][W][B][E][E][E][E][B][B][B]
[E][E][E][E][K][K][E][B][B][B]
[E][E][B][E][E][E][E][B][B][K]
[E][W][B][E][E][E][E][B][B][B]
[E][W][B][B][W][W][W][B][B][B]
[E][B][B][E][E][E][W][B][B][E]
[E][W][B][W][W][B][W][W][E][E]
[E][W][B][B][B][B][E][E][E][E]
[K][W][B][B][E][E][E][W][E][E]
[E][W][B][B][E][E][E][W][E][F]

Process finished with exit code 0

Answer 1

您错误地使用了面向对象编程。 Tile 不应扩展 Board。其次，Tile 应该自行处理绘图。

此外，不要每次都创建新的 Tile 对象(每次调用 repaint() 时)。读取文件后创建一次。您的 gameElements 现在可以被消除，因为您可以在文件读取期间创建 Tile 数组。

注意:下面，我通过 InputStream (Eclipse IDE) 将文件加载到 Scanner 中:

ClassLoader loader = Board.class.getClassLoader();
String filename = "resources/" + level + ".txt";
InputStream stream = loader.getResourceAsStream(filename);
Scanner scan = new Scanner(stream);

相反，您可以将 File 直接加载到 Scanner 构造函数中:

String filename = "path/to/file/" + level + ".txt";
File file = new File(filename);
Scanner scan = new Scanner(file);

<小时/>

Main.java

import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class Main {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                JComponent chart = new Board("1");

                frame.setSize(600, 600);
                frame.setTitle("SleutelBarricade");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLocationRelativeTo(null);
                frame.add(chart);
                frame.setVisible(true); 
            }
        });
    }
}

Board.java

import java.awt.Graphics;
import java.io.IOException;
import java.io.InputStream;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.swing.JComponent;

public class Board extends JComponent {
    private static final long serialVersionUID = 3669634976765884468L;

    public String[] gameElements = new String[100];
    private Tile[] tiles = new Tile[100];
    private String[][] map = new String[10][10];
    private String currentLevel;
    private boolean isInitialized;

    public Board(String level) {
        isInitialized = false;

        loadLevel(level);

        currentLevel = level;
        isInitialized = true;
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        if (isInitialized) {
            int i = 0;

            g.clearRect(0, 0, this.getWidth(), this.getHeight());

            for (int y = 0; y < map.length; y++) {
                for (int x = 0; x < map.length; x++) {
                    tiles[i].paintComponent(g);
                    map[y][x] = tiles[i].getLabel();
                    System.out.printf("[%s]", map[y][x]);
                    i++;
                }

                System.out.println();
            }
        }
    }

    public void readTextFile(String level) {
        ClassLoader loader = Board.class.getClassLoader();
        String filename = "resources/" + level + ".txt";
        InputStream stream = null;
        Scanner scan = null;

        try {
            stream = loader.getResourceAsStream(filename);
            scan = new Scanner(stream);

            scan.useDelimiter("[,]([\r\n]+)?");

            int i = 0;
            while (scan.hasNext()) {
                gameElements[i] = scan.next().trim();
                i++;
            }

            scan.close();
            stream.close();
        } catch (IOException e) {
            Logger.getLogger(Board.class.getName()).log(Level.SEVERE, null, e);
        }
    }

    private void generateTiles() {
        int i = 0;
        for (int y = 0; y < map.length; y++) {
            for (int x = 0; x < map.length; x++) {
                tiles[i] = new Tile(x, y, gameElements[i]);
                i++;
            }
        }
    }

    public void loadLevel(String level) {
        readTextFile(level);
        generateTiles();
    }
}

Tile.java

import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;

public class Tile {
    final private static int CELL_WIDTH = 50;
    final private static int CELL_HEIGHT = 50;

    final private static int BOARD_X_OFFSET = 25;
    final private static int BOARD_Y_OFFSET = 25;

    private int x;
    private int y;
    private String label;

    public int getX() {
        return x;
    }

    public void setX(int x) {
        this.x = x;
    }

    public int getY() {
        return y;
    }

    public void setY(int y) {
        this.y = y;
    }

    public String getLabel() {
        return label;
    }

    public void setLabel(String label) {
        this.label = label;
    }

    public Tile() {
        this(0, 0, "?");
    }

    public Tile(int x, int y, String label) {
        this.x = getScreenX(x);
        this.y = getScreenY(y);
        this.label = label;
    }

    private int getScreenX(int x) {
        return BOARD_X_OFFSET + (x * CELL_WIDTH);
    }

    private int getScreenY(int y) {
        return BOARD_Y_OFFSET + (y * CELL_HEIGHT);
    }

    public void paintComponent(Graphics g) {
        Font font = new Font("Arial", Font.BOLD, 16);
        FontMetrics metrics = g.getFontMetrics(font);
        int fontWidth = metrics.stringWidth(label);
        int fontHeight = metrics.getHeight();

        int xPos = x + BOARD_X_OFFSET - (fontWidth / 2);
        int yPos = y + BOARD_Y_OFFSET + (fontHeight / 2);

        g.setFont(font);
        g.setColor(Color.BLACK);
        g.drawRect(x, y, CELL_WIDTH, CELL_HEIGHT);
        g.drawString(label, xPos, yPos);
    }
}

1.txt

E,W,B,E,E,E,E,B,B,B,
E,E,E,E,K,K,E,B,B,B,
E,E,B,E,E,E,E,B,B,K,
E,W,B,E,E,E,E,B,B,B,
E,W,B,B,W,W,W,B,B,B,
E,B,B,E,E,E,W,B,B,E,
E,W,B,W,W,B,W,W,E,E,
E,W,B,B,B,B,E,E,E,E,
K,W,B,B,E,E,E,W,E,E,
E,W,B,B,E,E,E,W,E,F