今天我們要來繼續完善主畫面的內容，目前就剩下SettingPanel還沒有完成

建立SettingPanel

首先設定出SettingPanel，先暫時只給他一個回到主畫面的功能，先保證能夠流暢切換畫面剩下的後面再加

import javax.swing.*;
import java.awt.*;

public class SettingPanel extends JPanel{
    static final int PANEL_WIDTH = 800;
    static final int PANEL_HEIGHT = 500;

    // 接收GameFrame參數
    GameFrame gameFrame;
    // 回主畫面的按鈕
    JButton homeButton;

    SettingPanel(GameFrame frame){
        setButtons();
        this.setPreferredSize(new Dimension(PANEL_WIDTH, PANEL_HEIGHT));
        this.gameFrame = frame;
        this.setLayout(null);
        this.setBackground(Color.darkGray);
    }

    private void setButtons(){
        homeButton = new JButton("← Home");
        homeButton.setFont(new Font("Times New Roman", Font.ITALIC, 30));
        homeButton.setForeground(Color.WHITE);
        homeButton.setBackground(Color.darkGray);
        homeButton.setBorderPainted(false);
        homeButton.setBounds(25, 400, 200, 50);
        homeButton.addActionListener(e->gameFrame.showPanel("Menu"));

        this.add(homeButton);
    }
}

增加難度設置

接著我打算在Setting中增加設定難度的功能
要做到這點，需要先去學JRaidoButton和ButtonGroup的組合

// 先建立提示文字、3個難度選項與一個群組
JLabel setDifficulty;
JRadioButton easyButton;
JRadioButton mediumButton;
JRadioButton hardButton;
ButtonGroup difficultyGroup;

private void setDifficulty(){
    // 設置提示文字
    setDifficulty = new JLabel("Difficulty:");
    setDifficulty.setFont(new Font("MV Boli", Font.BOLD, 30));
    setDifficulty.setForeground(Color.WHITE);
    setDifficulty.setBackground(Color.darkGray);
    setDifficulty.setBounds(50, 90, 200, 50);

    // 設置按鈕資料
    easyButton = new JRadioButton("Easy");
    easyButton.setFont(difficultyFont);
    easyButton.setForeground(Color.WHITE);
    easyButton.setBackground(Color.darkGray);
    easyButton.setBorderPainted(false);
    easyButton.setFocusPainted(false);
    easyButton.setBounds(250, 100, 100, 30);
    
    // 設置按鈕的觸發事件，點擊時將難度設為easy（200ms更新一次的速度）
    easyButton.addActionListener(e->{
        difficulty = 200;
        gameFrame.setDifficulty(difficulty);
    });

    // 其他兩個也是
    mediumButton = new JRadioButton("Medium");
    mediumButton.setFont(difficultyFont);
    mediumButton.setForeground(Color.WHITE);
    mediumButton.setBackground(Color.darkGray);
    mediumButton.setBorderPainted(false);
    mediumButton.setFocusPainted(false);
    mediumButton.setBounds(400, 100, 150, 30);
    mediumButton.addActionListener(e->{
        difficulty = 150;
        gameFrame.setDifficulty(difficulty);
    });
    // 預設難度為medium，設置為預選
    mediumButton.setSelected(true);

    hardButton = new JRadioButton("Hard");
    hardButton.setFont(difficultyFont);
    hardButton.setForeground(Color.WHITE);
    hardButton.setBackground(Color.darkGray);
    hardButton.setBorderPainted(false);
    hardButton.setFocusPainted(false);
    hardButton.setBounds(600, 100, 150, 30);
    hardButton.addActionListener(e->{
        difficulty = 100;
        gameFrame.setDifficulty(difficulty);
    });

    // 設置群組，將三個RadioButton都加進去
    difficultyGroup = new ButtonGroup();
    difficultyGroup.add(easyButton);
    difficultyGroup.add(mediumButton);
    difficultyGroup.add(hardButton);

    // 然後分別將"每個"獨立的都加進去，群組不用加，群組是拿來綁定選項的
    this.add(setDifficulty);
    this.add(easyButton);
    this.add(mediumButton);
    this.add(hardButton);
}

接著GameFrame, GamePanel, GameOverPanel都需要有對應的difficulty變數與method，用於傳遞資料
GameFrame新增

private int difficulty = 150; // 初始設為medium難度，速度為150ms

// 兩個get&set method，用來修改與取得資料
public void setDifficulty(int difficulty){this.difficulty = difficulty;}
public int getDifficulty(){return difficulty;}

GamePanel修改預設速度邏輯，移除INITIAL_SPEED

int difficulty = 150; // 預設difficulty速度為150ms
int delay = difficulty; // 設置delay數值為difficulty(後續還會變動，所以用這個delay變數)
int scoreFactor = 4; // 修改難度邏輯，中等難度每4分升一級，簡單為5，困難為3

public void startGame(){
    // 確認遊戲要開始時，先取得使用者選擇的難度資料，並修改scoreFactor變數
    difficulty = gameFrame.getDifficulty();
    delay = difficulty;
    if(difficulty == 100) scoreFactor = 3;
    else if(difficulty == 150) scoreFactor = 4;
    else scoreFactor = 5;
}

private void move(){
    // 之前是3分就升一級，現在改為根據難度決定升級分數
    if(score % scoreFactor == 0 && level < 5){
        // ...
    }
}

最後是將difficulty傳給GameOverPanel，並顯示在結束畫面

String difficulty;

public void setScore(){
    this.score = gameFrame.getScore();
    int dif = gameFrame.getDifficulty();
    if(dif == 100) difficulty = "Hard";
    else if(dif == 150) difficulty = "Medium";
    else difficulty = "Easy";
    gameOverLabel2.setText("<html>You Scored " + score +
                           " in " + difficulty + "!</html>");
}

這樣就完成了可選擇的難度設置