我的图形有什么问题？

Question

第一次猜测时，应该显示的图形没有显示。 关于第八个猜测，根本没有显示任何图形。 （允许用户在失败前进行10次尝试）。 为什么会这样？ 感谢帮助！

HangmanFigure.java

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

public class HangmanFigure extends JPanel {
   private int guesses;
   private Image background;

      public HangmanFigure() {
         super();
         guesses = 0;
         setPreferredSize(new Dimension(400, 400));

         //setting background image to JPEG
         background = Toolkit.getDefaultToolkit().createImage("drac0.jpg");

         //set to true because we want to see the background
         setOpaque(true);
      }

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

         g.drawImage(background, 0, 0, null);

         //Testing number of guesses
         System.out.println(guesses);

         //right line
         if(guesses >= 1) {
            background = Toolkit.getDefaultToolkit().createImage("drac1.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //top and slant line
         if(guesses >= 2) {
            background = Toolkit.getDefaultToolkit().createImage("drac2.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //string
         if(guesses >= 3) {
            background = Toolkit.getDefaultToolkit().createImage("drac3.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //head
         if(guesses >= 4) {
            background = Toolkit.getDefaultToolkit().createImage("drac4.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //body
         if(guesses >= 5) {
            background = Toolkit.getDefaultToolkit().createImage("drac5.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //left arm
         if(guesses >= 6) {
            background = Toolkit.getDefaultToolkit().createImage("drac6.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //right hand
         if(guesses >= 7) {
            background = Toolkit.getDefaultToolkit().createImage("drac7.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //left leg
         if(guesses >= 8) {
            background = Toolkit.getDefaultToolkit().createImage("drac8.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //right leg
         if(guesses >= 9) {
            background = Toolkit.getDefaultToolkit().createImage("drac9.jpg");
            g.drawImage(background, 0, 0, null);
         }

         //death face and stake
         if(guesses == 10) {
            background = Toolkit.getDefaultToolkit().createImage("drac10.jpg");
            g.drawImage(background, 0, 0, null);
         }
      }

      public void set() {
         guesses++;
         paintComponent(this.getGraphics());
      }

这是我的MainWindow.java，在其中显示窗口中的所有其他内容：

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

public class MainWindow extends JFrame {
   private int remainingGuesses;
   private String wrongGuesses;
   private String word;
   private String visible;

   public MainWindow(String toGuess) {
      remainingGuesses = 10;
      wrongGuesses = "";
      word = toGuess;

      visible = "";

      for(int i = 0; i < word.length(); ++i) {
         visible += "_ ";
      }

      JPanel corePanel = new JPanel();
      corePanel.setLayout(new BorderLayout());

      final JLabel status = new JLabel("You have "+remainingGuesses+" remaining", SwingConstants.CENTER);
      final JLabel wrong = new JLabel("Wrong guesses so far: "+wrongGuesses);
      final JLabel visibleLabel = new JLabel(visible, SwingConstants.CENTER);
      final JTextField input = new JTextField();

      JPanel southPanel = new JPanel(new GridLayout(4, 1));
      southPanel.add(status);
      southPanel.add(visibleLabel);
      southPanel.add(input);
      southPanel.add(wrong);

      corePanel.add(southPanel, BorderLayout.SOUTH);

      final HangmanFigure hf = new HangmanFigure();
      corePanel.add(hf, BorderLayout.CENTER);

      this.add(corePanel, BorderLayout.CENTER);

      input.addActionListener(new ActionListener() {

         @Override
         public void actionPerformed(ActionEvent e) {
            String text = input.getText();

            if(text.length()  == 1 && text.matches("[a-z]")) {
               boolean guessFound = false;

               for(int i = 0; i < word.length(); ++i) {
                  if(text.charAt(0) == word.charAt(i)) {
                     guessFound = true;

                     String newVisible = "";

                     for(int j = 0; j < visible.length(); ++j) {
                        if(j == (i*2)) {
                           newVisible += word.charAt(i);
                        }
                        else {
                           newVisible += visible.charAt(j);
                        }
                     }
                     visible = newVisible;
                     visibleLabel.setText(visible);
                  }
               }

               if(!guessFound) {
                  if(--remainingGuesses > 0) {
                     status.setText("You have "+remainingGuesses+" guesses remaining");
                     wrongGuesses += text+" ";
                     wrong.setText("Wrong guesses so far: "+wrongGuesses);
                     hf.set();
                  }
                  else {
                     status.setText("You lost: the word was "+word);
                     input.setEnabled(false);
                  }
               }
               else {
                  String actualVisible = "";
                  for(int i = 0; i < visible.length(); i+=2) {
                     actualVisible += visible.charAt(i);
                  }

                  if(actualVisible.equals(word)) {
                     status.setText("Congratulations, you have won!");
                     input.setEnabled(false);
                  }
               }
            }
            else {
               //displays a dialogue box if user inputs anything other than lowercase letter.
               JFrame frame = new JFrame();
               JOptionPane.showMessageDialog(frame, "Please enter a lowercase letter!", "Inane warning", JOptionPane.WARNING_MESSAGE);
            }

            input.setText("");
         }
      });

      this.pack();
      this.setLocationRelativeTo(null);
      this.setTitle("Hangman");
      this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      this.setVisible(true);
   }

   public static void main(String[] args) {
      new MainWindow("cat");
   }
}

Answer 1

可能不是解决此问题的正确/最佳方法，我对Java Graphics没有任何经验。 但是，我看了一下drawImage函数，当图像准备好时它返回true。 因此，我尝试将调用包装在while循环中，现在它绘制了所有图像。

while(!g.drawImage(background, 0, 0, null));

请参阅API参考

带有IF语句的示例：

  try {

     .....

     if(guesses >= 1) {
        background = Toolkit.getDefaultToolkit().createImage("drac1.jpg");
        // old code - g.drawImage(background, 0, 0, null);
        while(!g.drawImage(background, 0, 0, null)) Thread.sleep(100); // - new code
     }

     if(guesses >= 2) {
        background = Toolkit.getDefaultToolkit().createImage("drac2.jpg");
        // old code - g.drawImage(background, 0, 0, null);
        while(!g.drawImage(background, 0, 0, null)) Thread.sleep(100); // - new code
     }

     .....

    } catch(InterruptedException ex) {
       ex.printStackTrace();
    }