JTable + JPopupMenu + ActionListener = Nightmare

Question

My main class is a window containing graphical components including a JTable.

I have created a public class ContextMenu which is a custom implementation of a JPopupMenu and containing multiple JMenuItem.

I have registered a mouseListener on my JTable to show an instance of ContextMenu when a right-click is detected.

The problem is the following: "How to pass the selected rows to different function according to the chosen JMenuItem?"

The obvious answer would be to set ActionListener on my JMenuItem but remember that JTable is in a different class/object than the JPopupMenu.

Some code snipets are worth a thousand words.

public class Tab implements ITab {
private ContextMenu contextMenu;
private JTable table;
private List<SomeObject> toProcess;
--- code --
private JScrollPane drawScrollTable() {
        Object columns[] = {
            "something",
            "somethingElse"
        };
        Object rows[][] = {};
        table = new JTable(new DefaultTableModel(rows, columns));
        JScrollPane scrollPane = new JScrollPane(table);

        table.setSelectionForeground(Color.BLACK);
        table.addMouseListener(new MouseAdapter() {         
            @Override
            public void mouseReleased(MouseEvent e) { 
                int selectedRow = table.rowAtPoint(e.getPoint());

                if (selectedRow >= 0 && selectedRow < table.getRowCount()) {
                    if (!table.getSelectionModel().isSelectedIndex(selectedRow)) {
                        table.setRowSelectionInterval(selectedRow, selectedRow);
                    }
                }

                if (e.isPopupTrigger() && e.getComponent() instanceof JTable) {  
                    this.show(e);
                }
            }

            private void show(MouseEvent e){
                contextMenu.show(e.getComponent(), e.getX(), e.getY());
            }
        });

        return scrollPane;
    }
-- code --
}

public class ContextMenu extends JPopupMenu {
    JMenuItem item;

    public ContextMenu(IBurpExtenderCallbacks callbacks){
        this.item= new JMenuItem("item");

        this.item(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {     
                 // Do action involving the selected row, even better if possible action involving the value hold in the column 0 of the selected row and the toProcess private field 
            }
        });

        add(item);
    }
}

I do not know if what I ask is possible.

Much better than posting code snippets -- create and post a valid [mcve], that is a **small** compilable and runnable program that demonstrates for us your *exact* problem. If you can do this, it will greatly enhance your chances of getting a decent answer. Note that all code and communication should be done here in your original question and not in a link. — Hovercraft Full Of Eels, Oct 07 '16 at 22:32

score 1 · Answer 1 · edited May 23 '17 at 12:24

Dirty way: pass references.
Cleaner way: structure your program via M-C-V

My Minimal, Complete, and Verifiable example of the dirty way:

import java.awt.BorderLayout;
import java.awt.event.*;

import javax.swing.*;
import javax.swing.table.DefaultTableModel;

public class TableTest extends JPanel {
    private TableClass tableClass = new TableClass();

    public TableTest() {
        setLayout(new BorderLayout());
        add(tableClass);
    }

    private static void createAndShowGui() {
        JFrame frame = new JFrame("TableTest");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new TableTest());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}

class ContextMenu extends JPopupMenu {
    private JMenuItem item;
    private TableClass tableClass;  // dirty direct reference *****

    public ContextMenu(TableClass tableClass){
        this.tableClass = tableClass;
        this.item= new JMenuItem("item");

        this.item.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {     
                int row = tableClass.getSelectedRow();
                JTable table = tableClass.getTable();
                System.out.println("row: " + row);
                StringBuilder sb = new StringBuilder("Data: ");
                for (int i = 0; i < table.getColumnCount(); i++) {
                    sb.append(table.getValueAt(row, i));
                    if (i != table.getColumnCount() - 1) {
                        sb.append(", ");
                    }
                }
                System.out.println(sb);
            }
        });

        add(item);
    }
}

class TableClass extends JPanel {
    // ***** passing **this** into the ContextMenu class
    private ContextMenu contextMenu = new ContextMenu(this); 
    private static final Integer[][] DATA = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
    private static final String[] COLUMN_NAMES = {"A", "B", "C"};
    private DefaultTableModel model = new DefaultTableModel(DATA, COLUMN_NAMES);
    private JTable table = new JTable(model);

    public TableClass() {
        table.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseReleased(MouseEvent e) {
                int selectedRow = table.rowAtPoint(e.getPoint());
                if (selectedRow >= 0 && selectedRow < table.getRowCount()) {
                    if (!table.getSelectionModel().isSelectedIndex(selectedRow)) {
                        table.setRowSelectionInterval(selectedRow, selectedRow);
                    }
                }
                if (e.isPopupTrigger() && e.getComponent() instanceof JTable) {
                    showPopUp(e);
                }
            }

            private void showPopUp(MouseEvent e) {
                contextMenu.show(e.getComponent(), e.getX(), e.getY());                
            }
        });

        setLayout(new BorderLayout());
        add(new JScrollPane(table));
    }

    public int getSelectedRow() {
        return table.getSelectedRow();
    }

    public int getSelectedColumn() {
        return table.getSelectedColumn();
    }

    public JTable getTable() {
        return table;
    }
}

Adrian Colomitchi · Accepted Answer · 2016-10-08T00:40:17.373

The MouseListener should collect all the relevant information for your ContextMenu, pack it in a transport (inner private?) class and pass this info before actually showing the context menu.

    table.addMouseListener(new MouseAdapter() {         
        @Override
        public void mouseReleased(MouseEvent e) { 
            int selectedRow = table.rowAtPoint(e.getPoint());

            if (selectedRow >= 0 && selectedRow < table.getRowCount()) {
                if (!table.getSelectionModel().isSelectedIndex(selectedRow)) {
                    table.setRowSelectionInterval(selectedRow, selectedRow);
                }
            }

            if (e.isPopupTrigger() && e.getComponent() instanceof JTable) {  
                this.show(e);
            }
        }

        private void show(MouseEvent e){
            int clickedRow=table.rowAtPoint(e.getPoint());
            int clickedCol=table.columnAtPoint(e.getPoint());
            Object data=table.getValueAt(row, i);

            DataClickedOnTable transportMeThere=new DataClickedOnTable(
              table, data, clickedRow, clickedColumn
            );
            contextMenu.setDataFromTable(transportMeThere);
            contextMenu.show(e.getComponent(), e.getX(), e.getY());
        }
    });
   ///....
   ///...


// Just an example of structure transporting the data
// Add whatever data members are relevant
private /* inner */ class DataClickedOnTable {
   public TestTable source;
   public Object data;
   public int row;
   public int column;

   public DataClickedOnTable(
     TestTable source, Object data, int row, int col
   ) {
     this.source=source;
     this.data=data;
     this.col=col;
     this.row=row;
   }
}
public class ContextMenu extends JPopupMenu {
    JMenuItem item1;
    JMenuItem item2; 

    Object dataFromTable; // make it an Integer 

    public ContextMenu(IBurpExtenderCallbacks callbacks){
        this.item1 = new JMenuItem("item");
        this.item2 = new JMenuItem("item");

        this.item1(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {     
                // You already have the relevant data in the dataFromTable
                // Do want you need in this context
            }
        });
        this.item2(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {     
                // You already have the relevant data in the dataFromTable
                // Do want you need to do in this context
            }
        });

        add(item1);
        add(item2);
    }

    void setDataFromTable(DataClickedOnTable data) {
      this.dataFromTable=data;
      // filter possible actions based on the received data - some
      // actions are possible, some won't.
      // Example:
      this.item1.setEnabled(null!=data && (data.row % 2)==0);
      this.item2.setEnabled(
            null!=data 
         && ((data.row % 2)==1 || data.data instanceof Number)
      );

    }
}

Many thanks for this solution, I reckon it might solve my issue and allow me to continue the development of my project. However, I do not understand why `DataClickedOnTable` should be a private inner class. Inner class of my `Tab` public class or inner class of my `ContextMenu` public class? — aress31, Oct 08 '16 at 10:00
@AresS31 " why DataClickedOnTable should be a private inner class." just a suggestion, not mandatory. But since it is meant to transport data only between your MouseListener and ContextMenu (which should be both inner classes of the frame supporting your table), it's a good practice not to make it accessible to other code which doesn't... ummm... need to know. — Adrian Colomitchi, Oct 08 '16 at 12:58
Ok, I see my ContextMenu is not an inner class I have made it a public class that is why I asked the question because when I made it private inner the ContextMenu had no access to it. I just made everything a public class. I will clean that up once the project over. Thanks again! — aress31, Oct 08 '16 at 15:36

JTable + JPopupMenu + ActionListener = Nightmare

2 Answers2