java图形抽绳未显示在JPanel中

Question

我正在尝试制作一个Java程序，允许您使用拖放代码面板编写简单的游戏。在我的代码面板中使用JTextField会产生一个小问题，在更新大小之前会有很长的延迟，因此我求助于使用JPanel创建自己的JTextField

代码如下：

package editor;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JPanel;
import javax.swing.border.LineBorder;

public class JCustomTextField extends JPanel {

    String text;
    int xMargin;
    int yMargin;
    int width;
    int height;

    public JCustomTextField(String initText, int xMargin, int yMargin, int height, int width) {

        this.xMargin = xMargin;
        this.yMargin = yMargin;
        this.width = width;
        this.height = height;
        this.text = initText;

        setBorder(new LineBorder(Color.DARK_GRAY, 2));
        setBounds(0, 0, width, height);


        addKeyListener(new KeyListener() {

            @Override
            public void keyPressed(KeyEvent arg0) {
                text.concat("" + arg0.getKeyChar());
                repaint();
            }

            @Override
            public void keyReleased(KeyEvent arg0) {

            }

            @Override
            public void keyTyped(KeyEvent arg0) {

            }

        });
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(Color.WHITE);
        g.drawString(text, xMargin, yMargin);
    }
    public Dimension getMinimumSize() {
        return new Dimension(width, height);
    }
    public Dimension getPreferredSize() {
        return new Dimension(width, height);
    }
    public Dimension getMaximumSize() {
        return new Dimension(width, height);
    }

}

现在，我创建了一个包含JLabel和文本面板的JComponent数组，并将其添加到代码面板中

JComponent[] jumpComps = {new JLabel("Jump Height:"), new JCustomTextField("10", 2, 2, 20, 50)};
    CodePanel jumpPanel = new CodePanel(0,0, jumpComps, 1);

显示边框，但不显示文本

下面是代码面板的图片：

我使用的是石墨玻璃的外观和感觉

Answer 1

从KeyEvent documentation开始：

The getKeyChar method always returns a valid Unicode character or CHAR_UNDEFINED. Character input is reported by KEY_TYPED events: KEY_PRESSED and KEY_RELEASED events are not necessarily associated with character input. Therefore, the result of the getKeyChar method is guaranteed to be meaningful only for KEY_TYPED events.

For key pressed and key released events, the getKeyCode method returns the event's keyCode. For key typed events, the getKeyCode method always returns VK_UNDEFINED.

getKeyChar仅对键类型事件有效。对于按键按下和按键释放事件，其返回值未定义

尽管如此，文本字段要比这个复杂得多。您没有处理光标渲染、退格、箭头键、选择或可访问性。最好使用真正的JTextField并正确地解决布局问题