CODEWITHSUNDEEP
javaswingjtable
Gibser
Gibser

Reputation: 327

Custom renderer with multi-line columns for JTable

I'm using a JTable created with NetBeans GUI Editor, I only changed the number of columns and names.

When I fill the table with SQL queries, strings that contain newlines are displayed on one line.

How can I solve it?

This is what I see by clicking on the table and on "Customize code" in Netbeans:

queryTableStatoPackage = new javax.swing.JTable();

queryTableStatoPackage.setModel(new javax.swing.table.DefaultTableModel(
    new Object [][] {

    },
    new String [] {
        "Nome Package", "ID Package", "Nome Progetto", "Codice Progetto", "Versione", "Stato", "Nota"
    }
));

jScrollPane10.setViewportView(queryTableStatoPackage);

enter image description here

"Nota" is the column involved

EDIT

Changes:

I created this class

package db_operation_package;

import java.awt.Component;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableCellRenderer;


public class NewLineSupportRenderer extends DefaultTableCellRenderer {

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row,
            int column) {
        Object val = value;
        if (val instanceof String) {
            val = convertNewLinesToHTML(val.toString());
        }
        return super.getTableCellRendererComponent(table, val, isSelected, hasFocus, row, column);
    }

    private String convertNewLinesToHTML(String s) {
        if (s.contains("\n")) {
            return "<html>" + s.replace("\n", "<br>") + "</html>";
        }
        return s;
    }

    public void updateRowHeight(JTable table, int margin) {
        final int rowCount = table.getRowCount();
        final int colCount = table.getColumnCount();
        for (int i = 0; i < rowCount; i++) {
            int maxHeight = 0;
            for (int j = 0; j < colCount; j++) {
                final TableCellRenderer renderer = table.getCellRenderer(i, j);
                maxHeight = Math.max(maxHeight, table.prepareRenderer(renderer, i, j).getPreferredSize().height);
            }
            table.setRowHeight(i, maxHeight + margin);
        }
    }
}

This is the code generated by netbeans for the table

queryTableStatoClasse = new javax.swing.JTable();

queryTableStatoClasse.setModel(new javax.swing.table.DefaultTableModel(
    new Object [][] {

    },
    new String [] {
        "Nome Classe", "Codice Classe", "Nome Progetto", "Codice Progetto", "Versione", "Stato", "Nota"
    }
));

jScrollPane9.setViewportView(queryTableStatoClasse);

I selected customize code and added this:

queryTableStatoClasse = new javax.swing.JTable();

queryTableStatoClasse.setModel(new javax.swing.table.DefaultTableModel(
    new Object [][] {

    },
    new String [] {
        "Nome Classe", "Codice Classe", "Nome Progetto", "Codice Progetto", "Versione", "Stato", "Nota"
    }
));

jScrollPane9.setViewportView(queryTableStatoClasse);

NewLineSupportRenderer customRenderer = new NewLineSupportRenderer();
queryTableStatoClasse.getColumnModel().getColumn(1).setCellRenderer(customRenderer);
customRenderer.updateRowHeight(queryTableStatoClasse, 0);

It doesn't seem to work, what am I doing wrong in modifying your code?

EDIT 2

It worked but this happens enter image description here

Upvotes: 1

Views: 287

Answers (1)

Sergiy Medvynskyy
Sergiy Medvynskyy

Reputation: 11327

You should convert your texts with new lines to the basic HTML presentation, that is supported by Swing. Best way to do it: use renderers. Also you need to update the row heights, because table don't make it automatically. Example:

import java.awt.Component;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;

/**
 * <code>TableExample</code>.
 */
public class TableExample {

    private static final String[][] TABLE_DATA = new String[][] {{"One", "String with one \nnew line"},
            {"Two", "String \nwith two \nnew lines"}, {"Three", "String \nwith \nmany \nnew \nlines"}};

    private class NewLineSupportRenderer extends DefaultTableCellRenderer {
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row,
                int column) {
            Object val = value;
            if (val instanceof String) {
                val = convertNewLinesToHTML(val.toString());
            }
            return super.getTableCellRendererComponent(table, val, isSelected, hasFocus, row, column);
        }
    }

    private String convertNewLinesToHTML(String s) {
        if (s.contains("\n")) {
            return "<html>" + s.replace("\n", "<br>") + "</html>";
        }
        return s;
    }

    private void initUI() {
        JTable table = new JTable(new DefaultTableModel(TABLE_DATA, new String[] {"Numbers", "Texts"}));
        table.getColumnModel().getColumn(1).setCellRenderer(new NewLineSupportRenderer());
        updateRowHeight(table, 0);
        JFrame frm = new JFrame("Table with new lines");
        frm.add(new JScrollPane(table));
        frm.pack();
        frm.setLocationRelativeTo(null);
        frm.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        frm.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new TableExample()::initUI);
    }

    private static void updateRowHeight(JTable table, int margin) {
        final int rowCount = table.getRowCount();
        final int colCount = table.getColumnCount();
        for (int i = 0; i < rowCount; i++) {
            int maxHeight = 0;
            for (int j = 0; j < colCount; j++) {
                final TableCellRenderer renderer = table.getCellRenderer(i, j);
                maxHeight = Math.max(maxHeight, table.prepareRenderer(renderer, i, j).getPreferredSize().height);
            }
            table.setRowHeight(i, maxHeight + margin);
        }
    }

}

Upvotes: 2

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