Question

我有一个文字JTextArea，其中包含一些突出显示的文字：

inputTextArea.getHighlighter().addHighlight(start, end, new DefaultHighlighter.DefaultHighlightPainter(new Color(color)));

虽然效果很好，但是如果我使用鼠标选择了一些文字，那么当它在突出显示的文本上时，选择不会被绘制。

例如，如果我只想选择突出显示文本的一部分，我看不到选择。

如何使选择显示在突出显示上？

Answer 1

您只需要一个代理荧光笔，可以修改绘画坐标。这是一个例子：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Shape;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.WindowConstants;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.Highlighter.HighlightPainter;
import javax.swing.text.JTextComponent;


public class HighlightTest {

    public static void main(String[] args) {
        JTextArea textArea = new JTextArea(10, 30);
        textArea.setText("It's a small test to understand whether proxy works or not.");
        try {
            textArea.getHighlighter().addHighlight(5, 15,
                    new ProxyHighlightPainer(new DefaultHighlighter.DefaultHighlightPainter(Color.RED)));
        } catch (Exception e) {
            // add something when required
        }
        textArea.addCaretListener(e -> textArea.repaint()); // must provoke repaint of highlighter
        JFrame frm = new JFrame("Test");
        frm.add(new JScrollPane(textArea));
        frm.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frm.pack();
        frm.setLocationRelativeTo(null);
        frm.setVisible(true);
    }
    private static class ProxyHighlightPainer implements HighlightPainter {

        private final HighlightPainter delegate;

        public ProxyHighlightPainer(HighlightPainter delegate) {
            this.delegate = delegate;
        }

        @Override
        public void paint(Graphics g, int p0, int p1, Shape bounds, JTextComponent c) {
            int startSel = c.getSelectionStart();
            int endSel = c.getSelectionEnd();
            if (startSel == endSel || startSel >= p1 || endSel <= p0) {
                // no selection or no intersection: paint normal
                delegate.paint(g, p0, p1, bounds, c);
            } else if (startSel >= p0 && endSel >= p1) {
                delegate.paint(g, p0, startSel, bounds, c);
            } else if (startSel <= p0 && endSel <= p1) {
                delegate.paint(g, endSel, p1, bounds, c);
            } else if (startSel <= p0 && endSel <= p1) {
                delegate.paint(g, p0, startSel, bounds, c);
                delegate.paint(g, endSel, p1, bounds, c);
            } else {
                // just to be safe
                delegate.paint(g, p0, p1, bounds, c);
            }
        }

    }
}

Answer 2

您可以使用：

JTextArea textArea = new JTextArea(10, 20);
textArea.setText( "one\ntwo\nthree\nfour\nfive\nsix\nseven\neight" );

DefaultHighlighter highlighter =  (DefaultHighlighter)textArea.getHighlighter();
highlighter.setDrawsLayeredHighlights(false);

try
{
    highlighter.addHighlight(10, 20, new DefaultHighlighter.DefaultHighlightPainter(Color.YELLOW));
}
catch(Exception e) {}

更改分层高光属性有两个效果：

您现在将看到选择
当突出显示的文本跨越多行时，突出显示行的文本区域的末尾（不仅仅是文本的末尾）。

Java在高亮文本上选择了文本

2 个答案: