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Java GUI编程实例:计算器和飞机大战游戏
2023-06-18 01:06:06 深夜i     --     --
Java GUI编程

我最近在学习Java GUI编程,并尝试了一些实例。

首先,我写了一个简单的计算器程序。下面是代码例子:


import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class Calculator extends JFrame implements ActionListener{

  private JTextField inputField;

  private JButton[] btns;

  private String[] btnValues = {"7", "8", "9", "/", "4", "5", "6", "*", "1", "2", "3", "-", "0", ".", "=", "+"};

  private boolean isFirstInput = true;

  private String operator = "";

  private double result = 0;

  public Calculator(){

    setTitle("Calculator");

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    setSize(180, 220);

    setResizable(false);

    inputField = new JTextField(15);

    inputField.setHorizontalAlignment(JTextField.RIGHT);

    inputField.setEditable(false);

    JPanel btnPanel = new JPanel();

    btnPanel.setLayout(new GridLayout(4, 4));

    btns = new JButton[16];

    for(int i=0; i

      btns[i] = new JButton(btnValues[i]);

      btns[i].addActionListener(this);

      btnPanel.add(btns[i]);

    }

    add(inputField, BorderLayout.NORTH);

    add(btnPanel, BorderLayout.CENTER);

    setVisible(true);

  }

  @Override

  public void actionPerformed(ActionEvent e){

    String input = e.getActionCommand();

    if(isFirstInput){

      inputField.setText("");

      isFirstInput = false;

    }

    if(input.equals("+") || input.equals("-") || input.equals("*") || input.equals("/")){

      operator = input;

      result = Double.parseDouble(inputField.getText());

      isFirstInput = true;

    }

    else if(input.equals("=")){

      double secondNum = Double.parseDouble(inputField.getText());

      if(operator.equals("+"))

        result += secondNum;

      else if(operator.equals("-"))

        result -= secondNum;

      else if(operator.equals("*"))

        result *= secondNum;

      else if(operator.equals("/"))

        result /= secondNum;

      inputField.setText(result + "");

      isFirstInput = true;

    }

    else{

      inputField.setText(inputField.getText() + input);

    }

  }

  public static void main(String[] args){

    new Calculator();

  }

}

运行程序,可以看到一个简单的计算器界面,支持加减乘除四则运算。

另外一个例子是一个简单的飞机大战游戏。下面是代码例子:


import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

import java.util.ArrayList;

import java.util.Random;

public class PlaneGame extends JFrame implements ActionListener{

  private JPanel gamePanel;

  private Timer timer;

  private ArrayList planes;

  private ArrayList bullets;

  private MyPlane myPlane;

  private int score = 0;

  public PlaneGame(){

    setTitle("Plane Game");

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    setResizable(false);

    setSize(600, 680);

    gamePanel = new JPanel(){

      @Override

      protected void paintComponent(Graphics g){

        super.paintComponent(g);

        for(Plane p: planes)

          p.draw(g);

        for(Bullet b: bullets)

          b.draw(g);

        if(myPlane != null)

          myPlane.draw(g);

        drawScore(g);

      }

    };

    gamePanel.setBackground(Color.WHITE);

    gamePanel.setLayout(null);

    add(gamePanel, BorderLayout.CENTER);

    timer = new Timer(10, this);

    planes = new ArrayList<>();

    bullets = new ArrayList<>();

    setVisible(true);

    startGame();

  }

  private void startGame(){

    myPlane = new MyPlane(gamePanel.getWidth() / 2 - 20, gamePanel.getHeight() - 100);

    planes.add(new EnemyPlane(50, 30));

    planes.add(new EnemyPlane(250, 10));

    planes.add(new EnemyPlane(450, 20));

    timer.start();

  }

  private void drawScore(Graphics g){

    g.setColor(Color.BLUE);

    g.setFont(new Font("Arial", Font.BOLD, 24));

    g.drawString("Score: " + score, 10, 30);

  }

  @Override

  public void actionPerformed(ActionEvent e){

    if(e.getSource() == timer){

      for(Plane p: planes)

        p.move(gamePanel);

      for(Bullet b: bullets)

        b.move();

      checkCollision();

      gamePanel.repaint();

      if(new Random().nextInt(100) < 5)

        planes.add(new EnemyPlane(new Random().nextInt(gamePanel.getWidth() - 60), 30));

      if(score >= 100)

        timer.stop();

    }

  }

  private void checkCollision(){

    for(Plane p: planes){

      if(!p.isAlive())

        continue;

      if(myPlane.hitTest(p)){

        myPlane.setAlive(false);

        timer.stop();

        JOptionPane.showMessageDialog(this, "Game Over!");

        return;

      }

      for(Bullet b: bullets){

        if(b.hitTest(p)){

          p.setAlive(false);

          b.setAlive(false);

          score++;

          break;

        }

      }

    }

    bullets.removeIf(b -> !b.isAlive());

    planes.removeIf(p -> !p.isAlive() && !(p instanceof MyPlane));

  }

  public static void main(String[] args){

    new PlaneGame();

  }

}

abstract class Plane{

  protected int x, y, width, height;

  protected Image image;

  protected boolean alive = true;

  public Plane(int x, int y, int width, int height, String imageUrl){

    this.x = x;

    this.y = y;

    this.width = width;

    this.height = height;

    image = new ImageIcon(getClass().getResource(imageUrl)).getImage();

  }

  public void move(JPanel container){

    y += 5;

    if(y > container.getHeight())

      alive = false;

  }

  public void draw(Graphics g){

    if(alive)

      g.drawImage(image, x, y, width, height, null);

  }

  public boolean isAlive()

    return alive;

  

  public void setAlive(boolean alive)

    this.alive = alive;

  

  public boolean hitTest(Plane plane){

    return x + width > plane.x && x < plane.x + plane.width && y + height > plane.y && y < plane.y + plane.height;

  }

}

class MyPlane extends Plane{

  public MyPlane(int x, int y){

    super(x, y, 40, 40, "/images/my_plane.png");

  }

}

class EnemyPlane extends Plane{

  public EnemyPlane(int x, int y){

    super(x, y, 60, 45, "/images/enemy_plane.png");

  }

  public EnemyPlane(int x, int y, int width, int height, String imageUrl){

    super(x, y, width, height, imageUrl);

  }

  @Override

  public void move(JPanel container){

    y += 10;

    if(y > container.getHeight())

      alive = false;

  }

}

class Bullet{

  private int x, y, speed;

  private Image image;

  private boolean alive = true;

  public Bullet(int x, int y, int speed){

    this.x = x;

    this.y = y;

    this.speed = speed;

    image = new ImageIcon(getClass().getResource("/images/bullet.png")).getImage();

  }

  public void move(){

    y -= speed;

    if(y < -10)

      alive = false;

  }

  public void draw(Graphics g){

    if(alive)

      g.drawImage(image, x, y, 10, 10, null);

  }

  public boolean isAlive()

    return alive;

  

  public void setAlive(boolean alive)

    this.alive = alive;

  

  public boolean hitTest(Plane plane){

    return x + 10 > plane.x && x < plane.x + plane.width && y + 10 > plane.y && y < plane.y + plane.height;

  }

}

运行程序,可以看到一个简单的飞机大战游戏界面。

三个 、计算器、飞机大战游戏。

一个

  
  
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