JTextField java?

Question

我的任务：

创建一个显示 10 个步骤的 Hangman 图形的应用程序。出于测试目的，该图形应可通过文本字段和滑块（范围 0-10）进行控制。值更改后，文本框会立即更新图形，并且不会等到按下 Enter 键。如果在文本字段中输入了无效值，则会显示错误消息而不是图形（使用方法drawString 文本也可以“绘制”），如果那里应该没有值，那么图形应该保留空。

在我的程序中，JSlider 上的图形更改工作正常，但通过文本字段输入不会导致任何更改，并且在输入错误值时进行检查，我尝试过，但没有显示任何内容。我不明白出了什么问题，因为JTextField 方法与JSlider 相同...

我已经把这两个类的源代码放在下面了。

头等舱：

进口、包装...

public class HangmanFrame extends JFrame{

public HangmanFrame(){

    super("Hangman");
    HangmanPanel panel = new HangmanPanel();
    JPanel mainPanel = new JPanel();
    this.add(mainPanel);
    mainPanel.setLayout(new BorderLayout());

    JTextField t = new JTextField();
    t.getDocument().addDocumentListener(new DocumentListener(){

        @Override
        public void changedUpdate(DocumentEvent arg0) {
            try{
                Integer.parseInt(t.getText());
            }
            catch(NumberFormatException ex){
                System.out.println(ex.getMessage());
            }
            panel.repaint();
        }

        @Override
        public void insertUpdate(DocumentEvent arg0) {
            try{
                Integer.parseInt(t.getText());
            }
            catch(NumberFormatException ex){
                System.out.println(ex.getMessage());
            }
            panel.repaint();

        }

        @Override
        public void removeUpdate(DocumentEvent arg0) {
            try{
                Integer.parseInt(t.getText());
            }
            catch(NumberFormatException ex){
                System.out.println(ex.getMessage());
            }
            panel.repaint();
        }
    });

    JSlider s = new JSlider(JSlider.HORIZONTAL, 0, 10, 0);

    s.addChangeListener(new ChangeListener(){

        @Override
        public void stateChanged(ChangeEvent arg0) {
            panel.repaint();
        }

    });

    panel.setSlider(s);
    panel.setTextField(t);
    mainPanel.add(panel, BorderLayout.CENTER);
    mainPanel.add(s, BorderLayout.PAGE_END);
    mainPanel.add(t, BorderLayout.PAGE_START);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.pack();
    this.setSize(300,500);
    this.setLocationRelativeTo(null);
    this.setVisible(true);
}

public static void main(String[] args) {
    new HangmanFrame();
}

}

二等：

public class HangmanPanel extends JPanel {

    private JSlider slider;
    private JTextField field; //Height 500, Width 300

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

        int sliderValue = slider.getValue();
        String fieldValue = field.getText();
        //int fieldInt = Integer.parseInt(fieldValue);

        g.drawLine(0, super.getWidth() + 99, super.getHeight(), super.getWidth() + 99); 

        if(sliderValue == 0 || fieldValue.equals("0")){
            return;
        }

        g.setColor(new Color(205,133,63));
        int xArc = this.getWidth() / 20;
        int yArc = this.getHeight() - this.getHeight() / 5;
        int arcWidth = this.getWidth() / 2;
        int arcHeight = this.getHeight() / 5;

        g.fillArc(xArc, yArc, arcWidth, arcHeight, 0, 180);

        if(sliderValue == 1 || fieldValue.equals("1")){
            return;
        }

        g.setColor(Color.BLACK);
        int x1Line = xArc + arcWidth / 2;
        int x2Line = x1Line;
        int y1Line = yArc;
        int y2Line = this.getHeight() / 6;

        g.drawLine(x1Line, y1Line, x2Line, y2Line);

        if(sliderValue == 2 || fieldValue.equals("2")){
            return;
        }

        int x3Line = x1Line;
        int x4Line = x3Line + (this.getWidth() / 3) + 20;
        int y3Line = y2Line;
        int y4Line = y3Line;

        g.drawLine(x3Line, y3Line, x4Line, y4Line);

        if(sliderValue == 3 || fieldValue.equals("3")){
            return;
        }

        int x5Line = x4Line;
        int x6Line = x5Line;
        int y5Line = y4Line;
        int y6Line = y5Line + this.getWidth() / 5; // + 60

        g.drawLine(x5Line, y5Line, x6Line, y6Line);

        if(sliderValue == 4 || fieldValue.equals("4")){
            return;
        }

        g.setColor(new Color(255, 221, 204));
        g.fillOval(x6Line - this.getHeight() / 20, y6Line, this.getHeight() / 10, this.getHeight() / 10); // -25, ...,50, 50

        if(sliderValue == 5 || fieldValue.equals("5")){
            return;
        }

        g.setColor(Color.BLUE);
        g.fillOval((int) ((int) x6Line - this.getHeight() / 14.7) , (int) (y6Line + this.getHeight() / 10.41), (int)(this.getHeight() / 7.14), (int)(this.getHeight() / 4.16)); // 34, 48, 70, 120                        

        if(sliderValue == 6 || fieldValue.equals("6")){
            return;
        }

        int x7Line = x6Line + (int)(this.getHeight() / 17.85); // 28
        int x8Line = x7Line + (int)(this.getHeight() / 12.5); // 40
        int y7Line = y6Line + (int)(this.getHeight() / 7.14); // 70
        int y8Line = y7Line - (int)(this.getHeight() / 14.28); // 35

        g.setColor(Color.BLACK);
        g.drawLine(x7Line, y7Line, x8Line, y8Line);

        if(sliderValue == 7 || fieldValue.equals("7")){
            return;
        }

        int x9Line = x7Line - (int)(this.getHeight() / 9.43); // 53
        int x10Line = x9Line - (int)(this.getHeight() / 14.28); // 35
        int y9Line = y7Line;
        int y10Line = y8Line;

        g.drawLine(x9Line, y9Line, x10Line, y10Line);

        if(sliderValue == 8 || fieldValue.equals("8")){
            return;
        }

        int x11Line = x7Line;
        int x12Line = x8Line;
        int y11Line = y7Line + (int)(this.getHeight() / 6.66); // 75
        int y12Line = y8Line + (int)(this.getHeight() / 3.33); // 150

        g.drawLine(x11Line, y11Line, x12Line, y12Line);

        if(sliderValue == 9 || fieldValue.equals("9")){
            return;
        }

        int x13Line = x9Line;
        int x14Line = x10Line;
        int y13Line = y11Line;
        int y14Line = y12Line;

        g.drawLine(x13Line, y13Line, x14Line, y14Line);

    }

    public void setSlider(JSlider slider){
        this.slider = slider;
    }

    public void setTextField(JTextField field){
        this.field = field;
    }

}

Answer 1

您的 JTextField 读取有效，但问题是您首先检查滑块的值，因此如果滑块检查为真，则方法短路。为了证明它工作正常，将滑块一直向右移动，然后在 JTextField 中输入 1 或 2。

如果这是我的项目并且我想测试这种效果，我会从绘画方法中获取所有逻辑，而是允许我的控制器更改观察类的状态值，调用 repaint() 然后绘制基于该状态的图像。

例如，像这样：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;

import javax.swing.*;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;

@SuppressWarnings("serial")
public class HangmanGUI2 extends JPanel {
    private HangmanModel model = new HangmanModel();
    private HangmanPanel2 panel2 = new HangmanPanel2(model);
    private JSlider slider = new JSlider(0, HangmanModel.MAX_VALUE, 0);
    private JTextField textField = new JTextField(10);

    public HangmanGUI2() {
        textField.getDocument().addDocumentListener(new DocumentListener() {

            @Override
            public void removeUpdate(DocumentEvent e) {
                updateModel(e);
            }

            @Override
            public void insertUpdate(DocumentEvent e) {
                updateModel(e);
            }

            @Override
            public void changedUpdate(DocumentEvent e) {
                updateModel(e);
            }

            private void updateModel(DocumentEvent e) {
                Document doc = e.getDocument();
                int length = doc.getLength();
                try {
                    String text = doc.getText(0, length);
                    int value = Integer.parseInt(text.trim());
                    setModelValue(value);
                } catch (BadLocationException e1) {
                    e1.printStackTrace();
                } catch (NumberFormatException e1) {
                    // Do Nothing
                }
            }
        });

        slider.setMajorTickSpacing(1);
        slider.setPaintTicks(true);
        slider.setPaintLabels(true);
        slider.addChangeListener(e -> {
            int value = slider.getValue();
            setModelValue(value);
        });

        setLayout(new BorderLayout());
        add(panel2);
        add(textField, BorderLayout.PAGE_START);
        add(slider, BorderLayout.PAGE_END);

//        new Timer(1000, e -> {
//            model.increment();
//            repaint();
//        }).start();  
    }

    protected void setModelValue(int value) {
        model.setValue(value);
        repaint();
    }

    private static void createAndShowGui() {
        HangmanGUI2 mainPanel = new HangmanGUI2();

        JFrame frame = new JFrame("HangmanGUI2");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(mainPanel);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}

class HangmanModel {
    public static final int MAX_VALUE = 9;
    private int value = 0;

    public int getValue() {
        return value;
    }

    public void increment() {
        setValue(getValue() + 1);
    }

    public void setValue(int value) {
        this.value = Math.min(value, MAX_VALUE);
        this.value = Math.max(this.value, 0);
    }    

}

@SuppressWarnings("serial")
class HangmanPanel2 extends JPanel {
    private HangmanModel model;
    private List<Image> images = ImageCreator.getImages();

    public HangmanPanel2(HangmanModel model) {
        this.model = model;
    }

    @Override
    public Dimension getPreferredSize() {
        if (isPreferredSizeSet() || images.size() == 0) {
            return super.getPreferredSize();
        }
        int w = images.get(0).getWidth(this);
        int h = images.get(0).getHeight(this);
        return new Dimension(w, h);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(images.get(model.getValue()), 0, 0, this);
    }
}

class ImageCreator {
    private static final int W = 284;
    private static final int H = 425;
    private static final Color BASE_COLOR = new Color(205, 133, 63);

    public static List<Image> getImages() {
        List<Image> images = new ArrayList<>();
        BufferedImage img = new BufferedImage(W, H, BufferedImage.TYPE_INT_ARGB);
        images.add(createImageCopy(img));
        Graphics2D g2 = img.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

        g2.setColor(BASE_COLOR);
        int xArc = W / 20;
        int yArc = H - H / 5;
        int arcWidth = W / 2;
        int arcHeight = H / 5;

        g2.fillArc(xArc, yArc, arcWidth, arcHeight, 0, 180);


        images.add(createImageCopy(img));

        // -----------------------------------------

        g2.setColor(Color.BLACK);
        int x1Line = xArc + arcWidth / 2;
        int x2Line = x1Line;
        int y1Line = yArc;
        int y2Line = H / 6;

        g2.drawLine(x1Line, y1Line, x2Line, y2Line);

        images.add(createImageCopy(img));

        // -----------------------------------------

        int x3Line = x1Line;
        int x4Line = x3Line + (W / 3) + 20;
        int y3Line = y2Line;
        int y4Line = y3Line;

        g2.drawLine(x3Line, y3Line, x4Line, y4Line);

        images.add(createImageCopy(img));

        // -----------------------------------------

        int x5Line = x4Line;
        int x6Line = x5Line;
        int y5Line = y4Line;
        int y6Line = y5Line + W / 5; // + 60

        g2.drawLine(x5Line, y5Line, x6Line, y6Line);

        // -----------------------------------------

        g2.setColor(new Color(255, 221, 204));
        g2.fillOval(x6Line - H / 20, y6Line, H / 10,
                H / 10); // -25, ...,50, 50

        images.add(createImageCopy(img));

        // -----------------------------------------

        g2.setColor(Color.BLUE);
        g2.fillOval((int) ((int) x6Line - H / 14.7),
                (int) (y6Line + H / 10.41), (int) (H / 7.14),
                (int) (H / 4.16)); // 34, 48, 70, 120

        images.add(createImageCopy(img));

        // -----------------------------------------

        int x7Line = x6Line + (int) (H / 17.85); // 28
        int x8Line = x7Line + (int) (H / 12.5); // 40
        int y7Line = y6Line + (int) (H / 7.14); // 70
        int y8Line = y7Line - (int) (H / 14.28); // 35

        g2.setColor(Color.BLACK);
        g2.drawLine(x7Line, y7Line, x8Line, y8Line);

        images.add(createImageCopy(img));

        // -----------------------------------------

        int x9Line = x7Line - (int) (H / 9.43); // 53
        int x10Line = x9Line - (int) (H / 14.28); // 35
        int y9Line = y7Line;
        int y10Line = y8Line;

        g2.drawLine(x9Line, y9Line, x10Line, y10Line);

        images.add(createImageCopy(img));

        // -----------------------------------------

        int x11Line = x7Line;
        int x12Line = x8Line;
        int y11Line = y7Line + (int) (H / 6.66); // 75
        int y12Line = y8Line + (int) (H / 3.33); // 150

        g2.drawLine(x11Line, y11Line, x12Line, y12Line);

        images.add(createImageCopy(img));

        // -----------------------------------------

        int x13Line = x9Line;
        int x14Line = x10Line;
        int y13Line = y11Line;
        int y14Line = y12Line;

        g2.drawLine(x13Line, y13Line, x14Line, y14Line);
        images.add(createImageCopy(img));

        g2.dispose();
        return images;
    }

    private static Image createImageCopy(BufferedImage img) {
        int w = img.getWidth();
        int h = img.getHeight();
        BufferedImage img2 = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
        Graphics g = img2.getGraphics();
        g.drawImage(img, 0, 0, null);
        g.dispose();
        return img2;
    }
}