《Java 核心技术 卷1》 笔记 第九章扩展 总结扫雷小项目（2） 扫雷图像+无雷区域扩展+数字提示

9.8.2 扫雷图像设置

我们注意到，点到有雷区域时，不会显示当前的雷，我们尝试用图像表达点到雷的效果：

扫到雷：

b.setIcon(new ImageIcon("src/resource/p1.png"));

输了之后的重置：

B.setIcon(null);

效果：

图片来源：https://www.iconfont.cn/collections/detail?spm=a313x.7781069.1998910419.dc64b3430&cid=29753

9.8.3 数字提示

如果点到无雷区域，应该有无雷区域扩展。为了方便看效果，把雷的个数扩展为20个。

无雷区域扩展意味着：

1. 要记录哪些区域是已经点击过，并将它们进行扩展（BFS+visited数组）

private void dfs(int i, int j){
        if(i<0 || i >= row || j < 0 || j >= col || visited[i][j] || hasSweeper[i][j])
            return;
        visited[i][j] = true;
        JButton b = posSweeper.get(i).get(j);
        b.setEnabled(false);
        --last;

        for(int x = 0; x < 4; x++){
            int l = i+direction[x];
            int c = j+direction[x+1];
            dfs(l,c);
        }

        int sweepCnt = getSweepCnt(i,j);
        if(sweepCnt>0){
            b.setText(""+sweepCnt);
        }
    }

1. 记录索引->按钮的映射关系，以便可以找到周围位置的按钮，设置已点击效果

int[] xy = sweeperPos.get(button);
posSweeper.putIfAbsent(xy[0],new HashMap<>());
posSweeper.get(xy[0]).put(xy[1],button);

9.8.4 设置数字提示

当扩展到有雷区域附近时，应该有数字提示周围剩余雷个数，为了方便看效果，宽高各设置为500：

周围8格雷个数检查：

private int getSweepCnt(int x, int y){
        int cnt = 0;
        for(int i = x-1; i <= x+1; i++){
            for(int j = y-1; j <= y+1; j++){
                if(i==x&&y==j) continue;
                if(i<0 || i >= row || j < 0 || j >= col) continue;
                if(hasSweeper[i][j]){
                    ++cnt;
                }
            }
        }
        return cnt;
    }

效果：

完整代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.*;

public class Main {
    public static  void main(String[] args) {
        Main solution = new Main();

        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                MineSweeperFrame MineSweeperFrame = new MineSweeperFrame();
                MineSweeperFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                MineSweeperFrame.setVisible(true);
            }
        });
    }

}

class MineSweeperFrame extends JFrame {
    public static final int W = 500;
    public static final int H = 500;
    Map<JButton,int[]> sweeperPos = new HashMap<>();
    Map<Integer,Map<Integer,JButton>> posSweeper = new HashMap<>();
    boolean[][] hasSweeper;
    boolean[][] visited;
    int sweepCnt = 30;
    int row = 10;
    int col = 10;
    int last = row*col;
    private final int[] direction = new int[]{-1,0,1,0,-1};
    Random r = new Random();
    public MineSweeperFrame(){
        setTitle("扫雷游戏");
        setSize(W,H);
        setLayout(new GridLayout(row,col));
        for(int i = 0; i < row; i++){
            for(int j = 0; j < col; j++){
                JButton button = new JButton();
                add(button);
                sweeperPos.put(button,new int[]{i,j});
                button.addActionListener(new Sweeper());

                int[] xy = sweeperPos.get(button);
                posSweeper.putIfAbsent(xy[0],new HashMap<>());
                posSweeper.get(xy[0]).put(xy[1],button);
            }
        }

        init();
    }

    private void init(){
        last = 100;
        for(JButton button:sweeperPos.keySet()){
            button.setEnabled(true);
            button.setIcon(null);
            button.setText("");


        }


        hasSweeper = new boolean[row][col];
        visited = new boolean[row][col];
        setSweeps();

    }

    private void setSweeps(){
        int x = 0;
        int y = 0;
        int total = row*col;
        for(int i = 0; i < sweepCnt; i++){
            do{
                int pos = r.nextInt(total);
                x = pos/col;
                y = pos%col;
            }while (hasSweeper[x][y]);
            hasSweeper[x][y] = true;
        }

        //输出，检查效果用
        for(int i = 0; i < row; i++){
            System.out.println(Arrays.toString(hasSweeper[i]));
        }
    }

    class Sweeper implements ActionListener{

        @Override
        public void actionPerformed(ActionEvent e) {
            JButton b = (JButton) e.getSource();
            int[] pos = sweeperPos.get(b);
            int i = pos[0];
            int j = pos[1];

            if(hasSweeper[i][j]){
                b.setIcon(new ImageIcon("src/resource/p1.png"));
                int selection = JOptionPane.showConfirmDialog(MineSweeperFrame.this,"你输了！","结果",
                        JOptionPane.DEFAULT_OPTION);
                init();

            }else {
                dfs(i,j);
                if(last == sweepCnt){
                    int selection = JOptionPane.showConfirmDialog(MineSweeperFrame.this,"你赢了！太棒了！","结果",
                            JOptionPane.DEFAULT_OPTION);
                    init();

                }
            }
        }
    }

    private void dfs(int i, int j){
        if(i<0 || i >= row || j < 0 || j >= col || visited[i][j] || hasSweeper[i][j])
            return;
        visited[i][j] = true;
        JButton b = posSweeper.get(i).get(j);
        b.setEnabled(false);
        --last;

        for(int x = 0; x < 4; x++){
            int l = i+direction[x];
            int c = j+direction[x+1];
            dfs(l,c);
        }

        int sweepCnt = getSweepCnt(i,j);
        if(sweepCnt>0){
            b.setText(""+sweepCnt);
        }
    }

    private int getSweepCnt(int x, int y){
        int cnt = 0;
        for(int i = x-1; i <= x+1; i++){
            for(int j = y-1; j <= y+1; j++){
                if(i==x&&y==j) continue;
                if(i<0 || i >= row || j < 0 || j >= col) continue;
                if(hasSweeper[i][j]){
                    ++cnt;
                }
            }
        }
        return cnt;
    }
}

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