Resize TAB spacing in Jtextpane

Question

I want to change the tab key of jTextPane because it has many spaces, for example:

It is currently found like this:

Uma casa azul 

// após TAB

                Uma casa azul 

And what I want would be like this :

Uma casa azul 

// após TAB

       Uma casa azul 

You can do it?

Follow an example of my code:

public class TAB extends javax.swing.JFrame {

    /**
     * Creates new form TAB
     */
    public TAB() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jScrollPane1 = new javax.swing.JScrollPane();
        jTextPane1 = new javax.swing.JTextPane();
        jLabel1 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jScrollPane1.setViewportView(jTextPane1);

        jLabel1.setText("Como mudar o TAB ?");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.TRAILING)
            .addGroup(layout.createSequentialGroup()
                .addGap(151, 151, 151)
                .addComponent(jLabel1)
                .addContainerGap(150, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap(24, Short.MAX_VALUE)
                .addComponent(jLabel1)
                .addGap(18, 18, 18)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 195, javax.swing.GroupLayout.PREFERRED_SIZE))
        );

        pack();
    }// </editor-fold>                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(TAB.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(TAB.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(TAB.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(TAB.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TAB().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JLabel jLabel1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextPane jTextPane1;
    // End of variables declaration                   
}

And that’s all the main class does :

 new TAB().setVisible(true);

Answer 1

Need to change the way the method nextTabStop() class ParagraphView works. In the example below, the constant TAB_SIZE is that you are setting the size between these tabs, in pixels, just change according to what you think is best for your component:

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

public class TabSizeEditorKit extends StyledEditorKit {

    public static final int TAB_SIZE=36;

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


    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 MyViewFactory implements ViewFactory {

        @Override
        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);
        }
    }


    static class CustomTabParagraphView extends ParagraphView {

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

        @Override
        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);
        }

    }
}

Which results in:

---

Reference:

• Default Tabstop size customization in Jeditorpane