ubuntu java swing jtextfield 插入符号自 java8 以来不可见（setXORMode 错误？）

Question

为什么插入符号在 java8（oracle 和 openjdk）及更高版本下变得不可见（按下按键或向左箭头后）？（它在 java7 下工作）。我在 ubuntu。它在 mac-os jdk1.8.0_51 和 windows jdk1.8.0_65 上运行良好。似乎与此 bug 相关联。它是 JTextField 特有的（不会出现在 JTextArea 上）。

来自 OverwritableTextField

public class OverWriteCaret extends DefaultCaret {
    protected static final int MIN_WIDTH = 8;
    private static final Logger logger = Logger.getLogger(OverWriteCaret.class.getName());

    public static void main(String[] args) {
        JFrame f = new JFrame("Big caret");
        JTextField tf = new JTextField(20);
        tf.setCaret(new OverWriteCaret());
        f.getContentPane().add(tf, "North");
        f.pack();
        f.setVisible(true);
    }
    @Override
    protected synchronized void damage(Rectangle r) {
        if (r == null)
            return;
        try {
            JTextComponent comp = getComponent();
            TextUI mapper = comp.getUI();
            Rectangle r2 = mapper.modelToView(comp, getDot() + 1);
            int largeur = r2.x - r.x;
            if (largeur == 0)
                largeur = MIN_WIDTH;
            comp.repaint(r.x, r.y, largeur, r.height);
            this.x = r.x;
            this.y = r.y;
            this.width = largeur;
            this.height = r.height;
        } catch (Exception e) {
            logger.info(e);
        }
    }
    @Override
    public void paint(Graphics g) {
        if (isVisible())
            try {
                JTextComponent comp = getComponent();
                TextUI mapper = comp.getUI();
                Rectangle r1 = mapper.modelToView(comp, getDot());
                Rectangle r2 = mapper.modelToView(comp, getDot() + 1);
                g = g.create();
                g.setColor(comp.getForeground());
                g.setXORMode(comp.getBackground());
                int largeur = r2.x - r1.x;
                if (largeur == 0) 
                    largeur = MIN_WIDTH;               
                g.fillRect(r1.x, r1.y, largeur, r1.height);
                g.dispose();
            } catch (Exception e) {
                logger.info(e);
            }
    }
}

Answer 1

找到另一个插入符，可以了

    public class FancyCaret extends DefaultCaret {
    private static final Logger logger = Logger.getLogger(FancyCaret.class.getName());

    protected synchronized void damage(Rectangle r) {
        if (r == null)
            return;

        x = r.x;
        y = r.y;
        height = r.height;
        if (width <= 0)
            width = getComponent().getWidth();

        repaint(); // calls getComponent().repaint(x, y, width, height)
    }

    @Override
    public void paint(Graphics g) {
        JTextComponent comp = getComponent();
        if (comp == null)
            return;

        int dot = getDot();
        Rectangle r;
        char dotChar;
        try {
            r = comp.modelToView(dot);
            if (r == null)
                return;
            dotChar = comp.getText(dot, 1).charAt(0);
        } catch (Exception e) {
            logger.info(e);
            return;
        }

        if ((x != r.x) || (y != r.y)) {
            repaint(); // erase previous location of caret
            x = r.x; // Update dimensions (width gets set later in this method)
            y = r.y;
            height = r.height;
        }

        if (dotChar == '\n') {
            width = r.height / 2;
            if (isVisible())
                g.fillRect(r.x, r.y, width, r.height);
            return;
        }

        g.setColor(comp.getCaretColor());
        g.setXORMode(comp.getBackground()); // do this to draw in XOR mode

        width = g.getFontMetrics().charWidth(dotChar);
        if (isVisible())
            g.fillRect(r.x, r.y, width, r.height);
    }
}

ubuntu java swing jtextfield 插入符号自 java8 以来不可见（setXORMode 错误？）

ubuntu java swing jtextfield caret invisible since java8 (setXORMode bug ?)

java

ubuntu

swing

caret