我来帮您分析 JEditorPane 与 HTMLEditorKit 的缩进操作相关功能。
JEditorPane 和 HTMLEditorKit 的缩进处理
JEditorPane 配合 HTMLEditorKit 支持 HTML 内容的显示和编辑，包括缩进功能,以下是关键实现方式：
HTML 缩进支持
import javax.swing.*;
import javax.swing.text.html.*;
import java.awt.*;
import java.io.*;
public class HTMLIndentExample {
public static void main(String[] args) {
JFrame frame = new JFrame("HTML Indent Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(600, 400);
JEditorPane editorPane = new JEditorPane();
editorPane.setEditorKit(new HTMLEditorKit());
editorPane.setContentType("text/html");
// 支持缩进的 HTML 内容
String htmlContent = "<html><body>" +
"<h1>缩进示例</h1>" +
"<div style='margin-left: 20px;'>" +
" <p>这是有缩进的段落</p>" +
" <ul>" +
" <li style='margin-left: 10px;'>列表项 1</li>" +
" <li style='margin-left: 20px;'>列表项 2</li>" +
" </ul>" +
"</div>" +
"</body></html>";
editorPane.setText(htmlContent);
editorPane.setEditable(true);
frame.add(new JScrollPane(editorPane));
frame.setVisible(true);
}
}
实现代码缩进操作
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.text.html.*;
import java.awt.event.*;
public class IndentActionExample {
public static void main(String[] args) {
JFrame frame = new JFrame("Indent Actions");
JEditorPane editor = new JEditorPane();
editor.setEditorKit(new HTMLEditorKit());
// 添加快捷键缩进操作
InputMap inputMap = editor.getInputMap(JComponent.WHEN_FOCUSED);
ActionMap actionMap = editor.getActionMap();
// 自定义缩进动作
Action indentAction = new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
insertIndent(editor);
}
};
// Ctrl+I 触发缩进
KeyStroke keyStroke = KeyStroke.getKeyStroke(
KeyEvent.VK_I, InputEvent.CTRL_DOWN_MASK);
inputMap.put(keyStroke, "indent");
actionMap.put("indent", indentAction);
frame.add(new JScrollPane(editor));
frame.setSize(600, 400);
frame.setVisible(true);
}
private static void insertIndent(JEditorPane editor) {
try {
Document doc = editor.getDocument();
int caretPos = editor.getCaretPosition();
// 插入缩进（4个空格）
doc.insertString(caretPos, " ", null);
} catch (BadLocationException ex) {
ex.printStackTrace();
}
}
}
自定义 HTML 解析器缩进
import javax.swing.text.html.parser.*;
import javax.swing.text.html.*;
import javax.swing.text.*;
import java.util.*;
public class CustomIndentParser extends HTMLDocument.HTMLReader {
private int indentLevel = 0;
private StringBuilder output = new StringBuilder();
public CustomIndentParser(HTMLDocument doc) {
super(doc);
}
@Override
public void handleStartTag(HTML.Tag t, MutableAttributeSet a, int pos) {
// 输出缩进
output.append(getIndent());
output.append("<").append(t.toString());
// 添加属性
Enumeration<?> names = a.getAttributeNames();
while (names.hasMoreElements()) {
Object name = names.nextElement();
output.append(" ").append(name).append("='")
.append(a.getAttribute(name)).append("'");
}
output.append(">\n");
indentLevel++;
}
@Override
public void handleEndTag(HTML.Tag t, int pos) {
indentLevel--;
output.append(getIndent());
output.append("</").append(t.toString()).append(">\n");
}
@Override
public void handleText(char[] data) {
output.append(getIndent());
output.append(data).append("\n");
}
private String getIndent() {
StringBuilder indent = new StringBuilder();
for (int i = 0; i < indentLevel; i++) {
indent.append(" "); // 每级2个空格
}
return indent.toString();
}
public String getFormattedOutput() {
return output.toString();
}
}
使用 HTMLEditorKit 的缩进属性
import javax.swing.text.html.*;
import javax.swing.text.*;
public class HTMLStyleIndent {
public static void main(String[] args) {
HTMLEditorKit kit = new HTMLEditorKit();
HTMLDocument doc = (HTMLDocument) kit.createDefaultDocument();
// 设置默认缩进样式
StyleSheet styleSheet = doc.getStyleSheet();
// 为不同元素设置缩进
styleSheet.addRule("body { " +
"margin-left: 10px; " +
"padding-left: 10px; " +
"}");
styleSheet.addRule("div { " +
"margin-left: 20px; " +
"padding-left: 15px; " +
"}");
styleSheet.addRule("ul { " +
"margin-left: 30px; " +
"padding-left: 20px; " +
"}");
styleSheet.addRule("li { " +
"text-indent: -5px; " +
"margin-left: 40px; " +
"}");
// 应用样式
JEditorPane editor = new JEditorPane();
editor.setEditorKit(kit);
editor.setDocument(doc);
}
}
高级缩进控制
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.text.html.*;
import java.awt.*;
public class AdvancedIndentControl {
public static void createIndentedEditor() {
JEditorPane editor = new JEditorPane();
HTMLEditorKit kit = new HTMLEditorKit();
HTMLDocument doc = new HTMLDocument();
editor.setEditorKit(kit);
editor.setDocument(doc);
// 设置视图属性
ViewFactory factory = kit.getViewFactory();
// 自定义缩进的 HTML 内容
String html = String.join("\n",
"<html>",
"<head>",
"<style>",
" .indent1 { margin-left: 20px; }",
" .indent2 { margin-left: 40px; }",
" .indent3 { margin-left: 60px; }",
" blockquote {",
" margin-left: 30px;",
" border-left: 3px solid #ccc;",
" padding-left: 15px;",
" }",
"</style>",
"</head>",
"<body>",
"<p>普通段落</p>",
"<p class='indent1'>缩进一级</p>",
"<p class='indent2'>缩进二级</p>",
"<blockquote>",
" <p>引用内容，自动缩进</p>",
" <p>继续引用内容</p>",
"</blockquote>",
"</body>",
"</html>"
);
editor.setText(html);
editor.setEditable(true);
JFrame frame = new JFrame();
frame.add(new JScrollPane(editor));
frame.setSize(600, 400);
frame.setVisible(true);
}
}
- CSS 样式控制：通过 CSS 的 margin-left、padding-left、text-indent 控制缩进
- HTML 元素：blockquote、ul/ol、dl 等标签提供自然缩进
- 自定义解析：可以扩展 HTML 解析器实现自定义缩进格式
- 缩进操作：通过 Action 实现缩进/取消缩进功能
- 样式表：利用 StyleSheet 统一管理缩进样式
这些技术可以灵活控制 JEditorPane 中的 HTML 内容缩进显示。
