最近我一直在研究Java文本编辑器项目,我想使用JTextPane
替换旧的JTextArea
以实现语法突出显示。但是,JTextPane
缺少JTextArea
中的方法(例如append()
,getLineStartOffset()
等),我想在我的课程MyTextPane
中重新实现这些方法(等级JTextPane
),但遇到了麻烦。
我当前的代码(只是一个小的自包含部分):
import java.awt.*;
import javax.swing.*;
import javax.swing.text.*;
public class MyTextPane extends JTextPane
{
public MyTextPane()
{
super();
}
public void append(String text)
{
try
{
Document doc = this.getDocument();
doc.insertString(doc.getLength(),text,null);
}
catch (BadLocationException ex)
{
//must succeed
throw new InternalError(ex.getMessage());
}
}
public void insert(String text, int pos)
{
try
{
this.getStyledDocument().insertString(pos,text,null);
}
catch (BadLocationException ex)
{
throw new IllegalArgumentException(ex);
}
}
public void replaceRange(String str, int start, int end)
{
try
{
Document doc = this.getDocument();
doc.remove(start,end-start);
doc.insertString(start,str,null);
}
catch (BadLocationException ex)
{
throw new IllegalArgumentException(ex);
}
}
public void setLineWrap(boolean isLineWrap)
{
/*
* implements later
*/
}
public boolean getLineWrap()
{
/*
* implements later
*/
return true;
}
public void setWrapStyleWord(boolean isWrapStyleWord)
{
/*
* implements later
*/
}
public boolean getWrapStyleWord()
{
/*
* implements later
*/
return true;
}
public void setTabSize(int size)
{
/*
* implements later
*/
}
public int getTabSize()
{
/*
* implements later
*/
return 4;
}
public int getLineCount()
{
//follow JTextArea implementation
Element root = this.getDocument().getDefaultRootElement();
return root.getElementCount();
}
public int getLineStartOffset(int line) throws BadLocationException
{
//follow JTextArea implementation
int count = this.getLineCount();
Document doc = this.getDocument();
if (line < 0)
{
throw new BadLocationException("Negative line", -1);
}
if (line >= count)
{
throw new BadLocationException("No such line", doc.getLength() + 1);
}
return doc.getDefaultRootElement().getElement(line).getStartOffset();
}
public int getLineEndOffset(int line) throws BadLocationException
{
//follow JTextArea implementation
int count = this.getLineCount();
Document doc = this.getDocument();
if (line < 0)
{
throw new BadLocationException("Negative line", -1);
}
if (line >= count)
{
throw new BadLocationException("No such line", doc.getLength() + 1);
}
int end = doc.getDefaultRootElement().getElement(line).getEndOffset();
return (line==count-1)?(end-1):end;
}
public int getLineOfOffset(int off) throws BadLocationException
{
//follow JTextArea implementation
Document doc = this.getDocument();
if (off < 0)
{
throw new BadLocationException("Can't translate offset to line", -1);
}
if (off > doc.getLength())
{
throw new BadLocationException("Can't translate offset to line", doc.getLength() + 1);
}
return doc.getDefaultRootElement().getElementIndex(off);
}
public static void main(String[] args)
{
final SimpleAttributeSet BOLD_SET = new SimpleAttributeSet();
StyleConstants.setBold(BOLD_SET, true);
StyleConstants.setForeground(BOLD_SET, new Color(0,0,125));
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
MyTextPane textPane = new MyTextPane();
frame.add(new JScrollPane(textPane), BorderLayout.CENTER);
frame.setSize(200,200);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
如您所见,我已经添加了一些方法,例如append()
。但是,我想不出任何控制换行策略的方法。
默认行为很奇怪:当有一个短字和一个长字时,
如果我连续输入没有空格的字符,
它首先看起来像是用文字包装。但是,当我继续输入字符时,
根本不包装。
有没有优雅的方法来控制JTextPane
的包装政策?换句话说,JTextPane
可以包含像JTextArea
这样的字吗?我发现了很多重复项(例如this,this和this)但找不到解决方案。提前谢谢。
答案 0 :(得分:3)
这是关于同一问题的讨论:Word wrapping behavior in JTextPane since Java 7。用户StanislavL(在Stack Overflow上似乎也非常活跃:StanislavL)提出的解决方案支持自动换行的解决方案适用于使用Java 8的解决方案。它使用自定义WrapEditorKit
作为JTextPane
的编辑器工具包(WrapEditorKit
类依次使用WrapColumnFactory
和WrapLabelView
类。
将此与NonWrappingTextPane example(来自Core Swing:Kim Topley的高级编程一书)相结合,可以切换换行:
import java.awt.*;
import javax.swing.*;
public class WrapTestApp extends JFrame {
public static void main(final String[] arguments) {
new WrapTestApp();
}
public WrapTestApp() {
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setBounds(800, 400, 200, 200);
getContentPane().setLayout(new BorderLayout());
final CustomTextPane textPane = new CustomTextPane(true);
final JScrollPane scrollPane = new JScrollPane(textPane);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
getContentPane().add(scrollPane, BorderLayout.CENTER);
textPane.setText("ExampleOfTheWrapLongWordWithoutSpaces");
setVisible(true);
}
}
CustomTextPane
类:
import javax.swing.*;
import javax.swing.text.*;
public class CustomTextPane extends JTextPane {
private boolean lineWrap;
public CustomTextPane(final boolean lineWrap) {
this.lineWrap = lineWrap;
if (lineWrap)
setEditorKit(new WrapEditorKit());
}
@Override
public boolean getScrollableTracksViewportWidth() {
if (lineWrap)
return super.getScrollableTracksViewportWidth();
else
return getParent() == null
|| getUI().getPreferredSize(this).width <= getParent().getSize().width;
}
private class WrapEditorKit extends StyledEditorKit {
private final ViewFactory defaultFactory = new WrapColumnFactory();
@Override
public ViewFactory getViewFactory() {
return defaultFactory;
}
}
private class WrapColumnFactory implements ViewFactory {
@Override
public View create(final Element element) {
final String kind = element.getName();
if (kind != null) {
switch (kind) {
case AbstractDocument.ContentElementName:
return new WrapLabelView(element);
case AbstractDocument.ParagraphElementName:
return new ParagraphView(element);
case AbstractDocument.SectionElementName:
return new BoxView(element, View.Y_AXIS);
case StyleConstants.ComponentElementName:
return new ComponentView(element);
case StyleConstants.IconElementName:
return new IconView(element);
}
}
// Default to text display.
return new LabelView(element);
}
}
private class WrapLabelView extends LabelView {
public WrapLabelView(final Element element) {
super(element);
}
@Override
public float getMinimumSpan(final int axis) {
switch (axis) {
case View.X_AXIS:
return 0;
case View.Y_AXIS:
return super.getMinimumSpan(axis);
default:
throw new IllegalArgumentException("Invalid axis: " + axis);
}
}
}
}