Better way of setting tab size in a JTextPane

Question

I was wondering if there is a better way of setting tab size?

FontMetrics fm = textPane.getFontMetrics(textPane.getFont()); // deprecated!
int cw = fm.stringWidth("    ");
float f = (float) cw;
TabStop[] tabs = new TabStop[50]; // this sucks

for (int i = 0; i < tabs.length; i++) {
    tabs[i] = new TabStop(f * (i + 1), TabStop.ALIGN_LEFT, TabStop.LEAD_NONE);
}

TabSet tabset = new TabSet(tabs);
StyleContext sc = StyleContext.getDefaultStyleContext();
AttributeSet aset = sc.addAttribute(SimpleAttributeSet.EMPTY, StyleConstants.TabSet, tabset);
textPane.setParagraphAttributes(aset, false);

Answer 1

From the link

import javax.swing.text.*;
import javax.swing.*;

public class TabSizeEditorKit extends StyledEditorKit {

    public static final int TAB_SIZE=36;

    public ViewFactory getViewFactory() {
        return new MyViewFactory();
    }

    static class MyViewFactory implements ViewFactory {

        public View create(Element elem) {
            String kind = elem.getName();
            if (kind != null) {
                if (kind.equals(AbstractDocument.ContentElementName)) {
                    return new LabelView(elem);
                } else if (kind.equals(AbstractDocument.ParagraphElementName)) {
                    return new CustomTabParagraphView(elem);
                } else if (kind.equals(AbstractDocument.SectionElementName)) {
                    return new BoxView(elem, View.Y_AXIS);
                } else if (kind.equals(StyleConstants.ComponentElementName)) {
                    return new ComponentView(elem);
                } else if (kind.equals(StyleConstants.IconElementName)) {
                    return new IconView(elem);
                }
            }

            return new LabelView(elem);
        }
    }

    public static void main(String[] args) {
        JFrame frame=new JFrame("Custom default Tab Size in EditorKit example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JEditorPane edit=new JEditorPane();
        edit.setEditorKit(new TabSizeEditorKit());
        try {
            edit.getDocument().insertString(0,"1\t2\t3\t4\t5", new SimpleAttributeSet());
        } catch (BadLocationException e) {
            e.printStackTrace(); 
        }
        frame.getContentPane().add(new JScrollPane(edit));

        frame.setSize(300,100);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }


    static class CustomTabParagraphView extends ParagraphView {

        public CustomTabParagraphView(Element elem) {
            super(elem);
        }

        public float nextTabStop(float x, int tabOffset) {
            TabSet tabs = getTabSet();
            if(tabs == null) {
                // a tab every 72 pixels.
                return (float)(getTabBase() + (((int)x / TAB_SIZE + 1) * TAB_SIZE));
            }

            return super.nextTabStop(x, tabOffset);
        }

    }
}