我如何编写代码来显示每个 JPanel 中的每个字母，以及如何旋转。（JFrame、NetBeans）

Question

我是 Java 的新手，我在 class 中被分配为以下问题开发代码，我只能做设计，之后我就没有了'不知道如何继续向每个按钮添加操作。

这是问题：

https://www.chegg.com/homework-help/questions-and-answers/write-java-application-creates-frame-similar-one-shown--four-letter-word-shown-four-panels-q52352988

如果有人解决过，请分享。提前感谢您的帮助！

Answer 1

由于这是家庭作业，我不会提供完整的代码。我会提供片段。

这是我创建的 GUI。我希望我可以将其显示为动画 GIF。

我添加了一个停止按钮来停止单词旋转。

我通过将问题分解成越来越小的步骤来编写代码，然后对每个步骤进行编码。在完成之前，我运行对 GUI 进行了多次测试。有些测试失败了，我不得不修改代码。

我写了 6 classes。主要class创建了JFrame，字母面板组，以及底部的控制面板。我写了一个 LetterPanel class 来创建一个字母面板。我写了 3 个 actionListener classes，一个是 JComboBox，一个是旋转按钮，一个是停止按钮。我写了一个 Animation class 每秒旋转字母。

这是我用来获得 4 种绿色阴影的颜色。

    Color[] colors = { new Color(50, 117, 1),
            new Color(65, 159, 0), new Color(88, 201, 5),
            new Color(107, 242, 2)
    };

设置主要 JPanel 来容纳 4 个 LetterPanel 对象有点棘手。这是我的做法。

    JPanel panel = new JPanel();
    panel.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0));

LetterPanel class 扩展了 JPanel 并覆盖了 paintComponent 方法。首先，我调用了 super.paintComponent 方法。始终先调用 super.paintComponent 方法。然后，我画了背景颜色。然后，我画了字母。

为了在每个 LetterPanel 中绘制字母，我使用了以下代码。

    /**
     * Draw a String centered in the middle of the panel.
     *
     * @param g2d The Graphics2D instance.
     * @param text The String to draw.
     * @param font The Font to draw with.
     */
    public void drawCenteredString(Graphics2D g2d,
            String text, Font font) {
        FontMetrics metrics = g2d.getFontMetrics(font);
        int x = (getWidth() - metrics.stringWidth(text)) / 2;
        int y = ((getHeight() - metrics.getHeight()) / 2) +
                metrics.getAscent();
        g2d.setFont(font);
        g2d.drawString(text, x, y);
    }

JComboBox actionListener 从 JComboBox 中获取选定的单词。 Oracle 教程 How to Use Combo Boxes 告诉您我是如何设置 JComboBox 这个词的。

旋转按钮 actionListener 检查是否两个 JCheckBox 字段都被选中。然后它检查是否没有检查 JCheckBox 字段。最后，它启动一个 Animation 线程。

停止按钮停止 Animation 线程。

Animation线程旋转单词并暂停 1 秒让您看到旋转。

这是运行循环。

    @Override
    public void run() {
        while (running) {
            updatePanel();
            sleep(1000L);
            if (leftSelected) {
                word = rotateLeft(word);
            } else {
                word = rotateRight(word);
            }
        }
    }

这是我的旋转方法。

    private String rotateLeft(String word) {
        return word.substring(1) + word.substring(0, 1);
    }

    private String rotateRight(String word) {
        return word.substring(word.length() - 1) +
                word.substring(0, word.length() - 1);
    }

编辑添加；

我忘了我已经回答了这个问题。时间已经过去了，所以我将 post 整个应用程序。我在 classes 中添加了额外的 classes，这样我就可以 post 将这段代码作为一个块。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class RotateWord implements Runnable {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new RotateWord());
    }

    private Animation animation;

    private JCheckBox leftBox;
    private JCheckBox rightBox;

    private JComboBox<String> wordComboBox;

    private JFrame frame;

    private LetterPanel[] letterPanel;

    private String word;

    public RotateWord() {
        this.word = "WORD";
    }

    @Override
    public void run() {
        frame = new JFrame("Rotate Word");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.add(createWordPanel(word), BorderLayout.CENTER);
        frame.add(createControlPanel(word),
                BorderLayout.AFTER_LAST_LINE);

        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private JPanel createWordPanel(String word) {
        JPanel panel = new JPanel();
        panel.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0));

        Color[] colors = { new Color(50, 117, 1),
                new Color(65, 159, 0), new Color(88, 201, 5),
                new Color(107, 242, 2)
        };

        letterPanel = new LetterPanel[word.length()];
        for (int i = 0; i < word.length(); i++) {
            letterPanel[i] = new LetterPanel(colors[i],
                    word.charAt(i));
            panel.add(letterPanel[i]);
        }

        return panel;
    }

    public void updateWordPanel(String word) {
        for (int i = 0; i < word.length(); i++) {
            letterPanel[i].setLetter(word.charAt(i));
            letterPanel[i].repaint();
        }
    }

    private JPanel createControlPanel(String word) {
        JPanel panel = new JPanel();

        String[] words = { "ABLE", "BATH", "EXIT", "WORD" };
        wordComboBox = new JComboBox<>(words);
        wordComboBox.setSelectedItem(word);
        wordComboBox.addActionListener(new WordListener());
        panel.add(wordComboBox);

        leftBox = new JCheckBox("Left");
        panel.add(leftBox);

        rightBox = new JCheckBox("Right");
        panel.add(rightBox);

        JButton rotateButton = new JButton("Rotate");
        rotateButton.addActionListener(new RotateListener());
        panel.add(rotateButton);

        JButton stopButton = new JButton("Stop");
        stopButton.addActionListener(new StopListener());
        panel.add(stopButton);

        return panel;
    }

    public class LetterPanel extends JPanel {

        private static final long serialVersionUID = 1L;

        private char letter;

        private Color backgroundColor;

        private Font font;

        public LetterPanel(Color backgroundColor, char letter) {
            this.backgroundColor = backgroundColor;
            this.letter = letter;
            this.font = getFont().deriveFont(96f)
                    .deriveFont(Font.BOLD);
            this.setPreferredSize(new Dimension(120, 200));
        }

        public void setLetter(char letter) {
            this.letter = letter;
        }

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

            Graphics2D g2d = (Graphics2D) g;
            g2d.setColor(backgroundColor);
            g2d.fillRect(0, 0, getWidth(), getHeight());

            g2d.setColor(Color.BLACK);
            drawCenteredString(g2d, Character.toString(letter),
                    font);
        }

        /**
         * Draw a String centered in the middle of the panel.
         *
         * @param g2d The Graphics2D instance.
         * @param text The String to draw.
         * @param font The Font to draw with.
         */
        public void drawCenteredString(Graphics2D g2d,
                String text, Font font) {
            FontMetrics metrics = g2d.getFontMetrics(font);
            int x = (getWidth() - metrics.stringWidth(text)) / 2;
            int y = ((getHeight() - metrics.getHeight()) / 2) +
                    metrics.getAscent();
            g2d.setFont(font);
            g2d.drawString(text, x, y);
        }

    }

    public class WordListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent event) {
            word = (String) wordComboBox.getSelectedItem();
            updateWordPanel(word);
        }

    }

    public class RotateListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent event) {
            boolean leftSelected = leftBox.isSelected();
            boolean rightSelected = rightBox.isSelected();

            if (leftSelected && rightSelected) {
                word = "OOPS";
                updateWordPanel(word);
                return;
            }

            if (!leftSelected && !rightSelected) {
                return;
            }

            word = (String) wordComboBox.getSelectedItem();
            updateWordPanel(word);

            animation = new Animation(leftSelected);
            new Thread(animation).start();
        }

    }

    public class StopListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent event) {
            if (animation != null) {
                animation.setRunning(false);
                animation = null;
            }
        }

    }

    public class Animation implements Runnable {

        private boolean leftSelected;

        private volatile boolean running;

        public Animation(boolean leftSelected) {
            this.leftSelected = leftSelected;
            this.running = true;
        }

        @Override
        public void run() {
            while (running) {
                updatePanel();
                sleep(1000L);
                if (leftSelected) {
                    word = rotateLeft(word);
                } else {
                    word = rotateRight(word);
                }
            }
        }

        public synchronized void setRunning(boolean running) {
            this.running = running;
        }

        private String rotateLeft(String word) {
            return word.substring(1) + word.substring(0, 1);
        }

        private String rotateRight(String word) {
            return word.substring(word.length() - 1) +
                    word.substring(0, word.length() - 1);
        }

        private void updatePanel() {
            SwingUtilities.invokeLater(new Runnable() {
                @Override
                public void run() {
                    updateWordPanel(word);
                }
            });
        }

        private void sleep(long duration) {
            try {
                Thread.sleep(duration);
            } catch (InterruptedException e) {
                // Deliberately left blank

            }
        }

    }

}

我如何编写代码来显示每个 JPanel 中的每个字母，以及如何旋转。（JFrame、NetBeans）

How do i write a code to display every letter in every JPanel, and how do I rotate. (JFrame, NetBeans)

java

swing

jpanel

jframe

编辑添加；

我如何编写代码来显示每个 JPanel 中的每个字母，以及如何旋转。 （JFrame、NetBeans）

How do i write a code to display every letter in every JPanel, and how do I rotate. (JFrame, NetBeans)

java

swing

jpanel

jframe

编辑添加；

我如何编写代码来显示每个 JPanel 中的每个字母，以及如何旋转。（JFrame、NetBeans）