# Combobox in JTable



## MathiasBauer (28. Jun 2009)

Hallo zusammen,

ich habe folgendes Problem:

Ich möchte gerne in einer Spalte einer JTable eine Kombobox einfügen.
Wenn ich jetzt aber einen Wert einer Kombobox auswähle, ändern sich alle Werte, aber nur beim ersten Mal der Auswahl. Sorry, aber ich stehe im Moment voll auf dem Schlauch...
Irgendwie müsste ich, glaube ich, das komplette Design ändern?!?

Vielen Dank im Voraus!


```
import java.awt.Dimension;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.table.DefaultTableModel;
 
public class ComboTable extends JFrame{
    /** Creates a new instance of ComboTable */
    Table table;
    public ComboTable() {
        table = new Table();
        JScrollPane scrollPane = new JScrollPane(table);
        JPanel panel = new JPanel();
        panel.add(scrollPane);
        
        Object [] rowData = {"Column 1","ComboBoxItem"};        
        DefaultTableModel model = (DefaultTableModel)table.getModel();
        model.insertRow(table.getModel().getRowCount(),rowData);
        model.insertRow(table.getModel().getRowCount(),rowData);
        model.insertRow(table.getModel().getRowCount(),rowData);
        model.insertRow(table.getModel().getRowCount(),rowData);
        
        getContentPane().add(panel);
        setSize(new Dimension(400,400));
        pack();
        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
    public void addRow(){
        Object [] rowData = {"Column 1","ComboBoxItem"};    
        DefaultTableModel model = (DefaultTableModel)table.getModel();
        model.insertRow(table.getModel().getRowCount(),rowData);
    }
    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new ComboTable().setVisible(true);
            }
        });
    }
}

import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;



public class Table extends JTable{
	DefaultTableModel model = new DefaultTableModel();


	public Table() {
		setModel(model);
		model.addColumn("Column 1");
		model.addColumn("ComboBox");
		String [] items = {"ITEM1","ITEM2"};
	
			getColumn("ComboBox").setCellEditor(new ComboBoxEditor(items));
			getColumn("ComboBox").setCellRenderer(new ComboBoxRenderer(items));
		
		setVisible(true);
	}

	public boolean isCellEditable(int row, int column) {
		boolean editable = true;
		if(column < 1){
			editable = false;//only edit combobox
		}
		return editable;
	}

}

import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
 
public class ComboBoxEditor extends DefaultCellEditor {
    JComboBox comboBox;
    public ComboBoxEditor(String[] items) {
    	super(new JComboBox(items));
    }
}
 
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.JComboBox;
import javax.swing.JTable;
import javax.swing.table.TableCellRenderer;
 
public class ComboBoxRenderer extends JComboBox implements TableCellRenderer {
    public ComboBoxRenderer(String[] items) {
        super(items);
        addItemListener(new ItemListener() 
        {
            public void itemStateChanged(ItemEvent e) {
              	System.out.println(e.getStateChange() == 1 ? getSelectedItem()+"in itemChanged" : "");
             }
        });
    }
    public ComboBoxRenderer() {
        super();
        addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println("ComboBox Action Performed");
            }
        });
    }
    public Component getTableCellRendererComponent(JTable table, Object value,
            boolean isSelected, boolean hasFocus, int row, int column) {
        if (isSelected) {
            setForeground(table.getSelectionForeground());
            super.setBackground(table.getSelectionBackground());
        } else {
            setForeground(table.getForeground());
            setBackground(table.getBackground());
        }
        
        // Select the current value
        setSelectedItem(value);
        return this;
    }
}
```


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## SlaterB (28. Jun 2009)

das Problem ist, dass der Anfangswert 'ComboBoxItem' im TableModel kein gültiger Wert für die ComboBoxen im Renderer/ Editor sind,
die kennen nur ITEM1/ 2 an, 
und da der Aufruf 'zeige aktuellen Wert ComboBoxItem' nicht funktioniert ist quasi der vorherige Wert noch zu sehen


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## MathiasBauer (28. Jun 2009)

Vielen Dank. Jetzt geht es...


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## MathiasBauer (19. Jul 2009)

Okay, ich kriege es doch nicht hin...

Ich habe es nochmal mit einem anderen Beispiel probiert...
Wenn ich das Beispiel nur mit 2 Comboboxeinträgen laufen lassen, ändern sich alle Einträge mit, mit mehreren Einträgen geht es allerdings!
Hauptsächlich spielt sich das Problem, denke ich, in der Methode setUpSportColumn ab.

Vielen Dank im Voraus!


```
/*
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 * modification, are permitted provided that the following conditions
 * are met:
 *
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 *     notice, this list of conditions and the following disclaimer.
 *
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 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

/*
 * TableRenderDemo.java requires no other files.
 */

import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;

/** 
 * TableRenderDemo is just like TableDemo, except that it
 * explicitly initializes column sizes and it uses a combo box
 * as an editor for the Sport column.
 */
public class TableRenderDemo extends JPanel {
    private boolean DEBUG = false;

    public TableRenderDemo() {
        super(new GridLayout(1,0));

        JTable table = new JTable(new TableModel());
        table.setPreferredScrollableViewportSize(new Dimension(500, 70));
        table.setFillsViewportHeight(true);

        //Create the scroll pane and add the table to it.
        JScrollPane scrollPane = new JScrollPane(table);

        //Set up column sizes.
        initColumnSizes(table);

        //Fiddle with the Sport column's cell editors/renderers.
        setUpSportColumn(table, table.getColumnModel().getColumn(2));

        //Add the scroll pane to this panel.
        add(scrollPane);
    }

    /*
     * This method picks good column sizes.
     * If all column heads are wider than the column's cells'
     * contents, then you can just use column.sizeWidthToFit().
     */
    private void initColumnSizes(JTable table) {
        TableModel model = (TableModel)table.getModel();
        TableColumn column = null;
        Component comp = null;
        int headerWidth = 0;
        int cellWidth = 0;
        Object[] longValues = model.longValues;
        TableCellRenderer headerRenderer =
            table.getTableHeader().getDefaultRenderer();

        for (int i = 0; i < 5; i++) {
            column = table.getColumnModel().getColumn(i);

            comp = headerRenderer.getTableCellRendererComponent(
                                 null, column.getHeaderValue(),
                                 false, false, 0, 0);
            headerWidth = comp.getPreferredSize().width;

            comp = table.getDefaultRenderer(model.getColumnClass(i)).
                             getTableCellRendererComponent(
                                 table, longValues[i],
                                 false, false, 0, i);
            cellWidth = comp.getPreferredSize().width;

            if (DEBUG) {
                System.out.println("Initializing width of column "
                                   + i + ". "
                                   + "headerWidth = " + headerWidth
                                   + "; cellWidth = " + cellWidth);
            }

            column.setPreferredWidth(Math.max(headerWidth, cellWidth));
        }
    }

    public void setUpSportColumn(JTable table,
                                 TableColumn sportColumn) {
        //Set up the editor for the sport cells.
        JComboBox comboBox = new JComboBox();
        comboBox.addItem("Snowboarding");
        comboBox.addItem("Rowing");
        comboBox.addItem("Knitting");
        comboBox.addItem("Speed reading");
        comboBox.addItem("Pool");
        comboBox.addItem("None of the above");
        sportColumn.setCellEditor(new DefaultCellEditor(comboBox));

        String[] values = new String[comboBox.getItemCount()];
        for(int i=0;i<comboBox.getItemCount();i++){
        	values[i]=(String) comboBox.getItemAt(i);
        }
        ComboBoxRenderer comboBoxRenderer = new ComboBoxRenderer(values);
        comboBoxRenderer.setToolTipText("Click for combo box");
        sportColumn.setCellRenderer(comboBoxRenderer);
    }

    class TableModel extends AbstractTableModel {
        private String[] columnNames = {"First Name",
                                        "Last Name",
                                        "Sport",
                                        "# of Years",
                                        "Vegetarian"};
        private Object[][] data = {
            {"Mary", "Campione",
             "Snowboarding", new Integer(5), new Boolean(false)},
            {"Alison", "Huml",
             "Rowing", new Integer(3), new Boolean(true)},
            {"Kathy", "Walrath",
             "Knitting", new Integer(2), new Boolean(false)},
            {"Sharon", "Zakhour",
             "Speed reading", new Integer(20), new Boolean(true)},
            {"Philip", "Milne",
             "Pool", new Integer(10), new Boolean(false)}
        };

        public final Object[] longValues = {"Sharon", "Campione",
                                            "None of the above",
                                            new Integer(20), Boolean.TRUE};

        public int getColumnCount() {
            return columnNames.length;
        }

        public int getRowCount() {
            return data.length;
        }

        public String getColumnName(int col) {
            return columnNames[col];
        }

        public Object getValueAt(int row, int col) {
            return data[row][col];
        }

        /*
         * JTable uses this method to determine the default renderer/
         * editor for each cell.  If we didn't implement this method,
         * then the last column would contain text ("true"/"false"),
         * rather than a check box.
         */
        public Class getColumnClass(int c) {
            return getValueAt(0, c).getClass();
        }

        /*
         * Don't need to implement this method unless your table's
         * editable.
         */
        public boolean isCellEditable(int row, int col) {
            //Note that the data/cell address is constant,
            //no matter where the cell appears onscreen.
            if (col < 2) {
                return false;
            } else {
                return true;
            }
        }

        /*
         * Don't need to implement this method unless your table's
         * data can change.
         */
        public void setValueAt(Object value, int row, int col) {
            if (DEBUG) {
                System.out.println("Setting value at " + row + "," + col
                                   + " to " + value
                                   + " (an instance of "
                                   + value.getClass() + ")");
            }

            data[row][col] = value;
            fireTableCellUpdated(row, col);

            if (DEBUG) {
                System.out.println("New value of data:");
                printDebugData();
            }
        }

        private void printDebugData() {
            int numRows = getRowCount();
            int numCols = getColumnCount();

            for (int i=0; i < numRows; i++) {
                System.out.print("    row " + i + ":");
                for (int j=0; j < numCols; j++) {
                    System.out.print("  " + data[i][j]);
                }
                System.out.println();
            }
            System.out.println("--------------------------");
        }
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("TableRenderDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        TableRenderDemo newContentPane = new TableRenderDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

import java.awt.Component;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.JComboBox;
import javax.swing.JTable;
import javax.swing.table.TableCellRenderer;
 
public class ComboBoxRenderer extends JComboBox implements TableCellRenderer {
	public ComboBoxRenderer(String[] items) {
        super(items);
        addItemListener(new ItemListener() 
        {
            public void itemStateChanged(ItemEvent e) {
              	System.out.println(e.getStateChange() == ItemEvent.SELECTED ? getSelectedItem()+" in itemChanged" : "");
             }
        });
       
    }
    public Component getTableCellRendererComponent(JTable table, Object value,
            boolean isSelected, boolean hasFocus, int row, int column) {
        if (isSelected) {
            setForeground(table.getSelectionForeground());
            setBackground(table.getSelectionBackground());
        } else {
            setForeground(table.getForeground());
            setBackground(table.getBackground());
        }
        setSelectedItem(value);
        
        return this;
    }
}
```


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## MathiasBauer (24. Jul 2009)

Falls es jemanden interessieren sollte, die Anwort steht hier


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