按下按鈕后如何繪制橢圓形？ 日食？

Question

好的，我有一個游戲的標題屏幕（例如，游戲標題，播放按鈕，自定義按鈕，設置按鈕和退出按鈕）。

我所做的是使用痛苦組件繪制了一個Circle，並且還使用了keyListener，這樣一旦按下箭頭鍵，它將朝該方向移動。 它的作用是，一旦我運行代碼，它將顯示我的標題屏幕以及我繪制的球。

但這不是我堅持的目標。 我需要幫助的是，我不希望在運行代碼時這么快就看到標題屏幕上的球。 我希望球在我按下“播放”按鈕時出現，而不是在我打開或運行游戲時出現。

我嘗試使用actionListener，但是沒有用。 因此，如果您能幫助我解決此問題，那就太好了。

我的GamePanel類別：

package patel.Jainam;

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class GamePanel extends JPanel implements ActionListener, KeyListener  { 

  Timer tm = new Timer(5,this);
  int x = 0;
  int y = 0;
  int velX = 0;
  int velY = 0;
  private static final long serialVersionUID = 1L;

  private JLabel welcomeScreen;

  private JButton playButton;
  private JButton custButton;
  private JButton settButton;
  private JButton quitButton;

  private JButton backButton;

  public GamePanel () {

    tm.start();
    addKeyListener(this);
    setFocusable(true);
    setFocusTraversalKeysEnabled(false);
    setBackground(Color.black);

    welcomeScreen = new JLabel (" Fall Down 4 ", SwingConstants.CENTER);    
    welcomeScreen.setFont(new Font("Times New Roman", Font.ITALIC, 100));
    welcomeScreen.setForeground(Color.white);
    add(welcomeScreen);
    welcomeScreen.setVisible(true);

    playButton = new JButton (" Play ");
    playButton.setFont(new Font("Times New Roman", Font.ITALIC, 90));
    playButton.setBackground(Color.black);
    playButton.setForeground(Color.GREEN);
    add(playButton);
    playButton.setVisible(true);
    playButton.addActionListener(new drawBallListener());

    custButton = new JButton (" Customize ");
    custButton.setFont(new Font("Times New Roman", Font.ITALIC, 95));
    custButton.setBackground(Color.black);
    custButton.setForeground(Color.GREEN);
    add(custButton);
    custButton.setVisible(true);

    settButton = new JButton (" Settings ");
    settButton.setFont(new Font("Times New Roman", Font.ITALIC, 60));
    settButton.setBackground(Color.black);
    settButton.setForeground(Color.GREEN);
    add(settButton);
    settButton.setVisible(true);

    quitButton = new JButton (" Quit ");
    quitButton.setFont(new Font("Times New Roman", Font.ITALIC, 60));
    quitButton.setBackground(Color.black);
    quitButton.setForeground(Color.GREEN);
    add(quitButton);
    quitButton.setVisible(true);

    backButton = new JButton (" Go Back ");
    backButton.setFont(new Font("Times New Roman", Font.ITALIC, 50));
    backButton.setBackground(Color.black);
    backButton.setForeground(Color.GREEN);
    add(backButton);
    backButton.setVisible(false);

  }


  private class drawBallListener implements ActionListener {      
  public void paintComponent(Graphics g){

      super.paintComponent(g);
      g.setColor(Color.RED);
      g.fillOval(x, y, 50, 30);
      g.setVisible(false); 

  }
  }

  @Override
  public void keyPressed(KeyEvent e) {

    int ballMovement = 5;
    int c = e.getKeyCode();

    if (c == KeyEvent.VK_LEFT){
      velX = -ballMovement;
      velY = 0;

    } else if (c == KeyEvent.VK_RIGHT){
      velX = ballMovement;
      velY = 0;
    }
  }

  @Override
  public void keyReleased(KeyEvent e) {
    velX = 0;
    velY = 0;

  }

  @Override
  public void keyTyped(KeyEvent arg0) {    

  }

  public void actionPerformed(ActionEvent e) {  

    if(x < 0){
      velX = 0;
      x = 0;
    }

    if (x > 600){
      velX = 0;
      x = 600;
    }

    if (y < 0){
      velY = 0;
      y = 0;
    }

    if (y > 499){
      velY = 0;
      y = 499;
    }

    x = x +  velX;
    y  = y + velY;    
    repaint();    
  } 
} 

我的司機：

package patel.Jainam;

import javax.swing.*;

public class driver {

    public static void main(String[] args) {

    JFrame frame = new JFrame(" Fall Down 4 ");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add(new GamePanel());  
    frame.pack();
    frame.setResizable(false);
    frame.setVisible(true);   
    frame.setSize(728, 500);    
  }
} 

Answer 1

Change your mouseClick(...) to:

 int x, y;

   public void mouseClicked(MouseEvent e) {
  x = e.getX();
   y = e.getY();

  repaint();
 }

覆蓋油漆（...）：

 @Override
    public void paint(Graphics g) {
      drawCircle(x, y);
    }