java - JTextField java？

Question

我的任务:

Create an application that displays a Hangman graphic for 10 steps. This graphic should be controllable via a text field and a slider (in the range 0-10) for test purposes. The text box updates the graph as soon as the value is changed and does not wait until the Enter key is pressed. If an invalid value is entered in the text field, then an error message is displayed instead of the graphic (with the method drawString text can also be "drawn"), if there should be no value there, then the graphic should remain empty.

在我的程序中，JSlider 上图形的更改工作正常，但是通过文本字段的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，但没有任何结果被展示。我不明白出了什么问题，因为 JTextField 方法与 JSlider ...

我已将这两个类的源代码放在下面。

头等舱:

导入、打包...

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();
}

}

第二类:

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 slider 的值，因此如果 slider 检查为 true，则该方法会短路。要证明它有效，请将 slider 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，我将从绘画方法中获取所有逻辑，并允许我的 Controller 更改观察到的类的状态值，调用 repaint() 然后根据该状态绘制图像。

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;
    }
}