Dynamic jcombobox items inside jtable

问题

I am trying to create a Jtable with two combobox in each row. I have checked for tutorials on that and found that I can add static data inside combobox. But how come I can have dynamic data loaded into a combobox.

Even, whenever the user selects the combobox 1 from the row, then based on that, the combobox 2 will be updated.

Can anybody help me on this?

If I do removeAllItems() from the combobox, then the combobox 2 will updated, but I am unable to add new entries.

Thanks in advance.

回答1:

Table has two columns both are rendered as JComboBox. Now, selection of Column-2 items are dependent on the Column-1 selection.

import java.awt.Component;
import java.awt.EventQueue;
import java.util.ArrayList;
import java.util.List;

import javax.swing.DefaultCellEditor;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;


public class ComboBoxExample {

    private void createUI() {

        JFrame frame = new JFrame();

        Object[] columNames = {"Combo-1", "Combo-2"};
        Object[][] data = {{"", ""}, {"", ""}, {"", ""}, {"", ""}};

        JTable table = new JTable(data, columNames);

        table.getColumnModel().getColumn(0).setCellEditor(new CustomComboBoxEditor());
        table.getColumnModel().getColumn(1).setCellEditor(new CustomComboBoxEditor());

        frame.add(new JScrollPane(table));
        frame.setTitle("Column -2 based on Column - 1 ComboBox Selection.");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        Runnable r = new Runnable() {

            @Override
            public void run() {
                new ComboBoxExample().createUI();
            }
        };

        EventQueue.invokeLater(r);
    }

}

class CustomComboBoxEditor extends DefaultCellEditor {

    // Declare a model that is used for adding the elements to the `ComboBox`
    private DefaultComboBoxModel model;

    private List<String> obtainedList;

    public CustomComboBoxEditor() {
        super(new JComboBox());
        this.model = (DefaultComboBoxModel)((JComboBox)getComponent()).getModel();
        obtainedList = new ArrayList<String>();

        obtainedList.add("One");
        obtainedList.add("Two");
        obtainedList.add("Three");
        obtainedList.add("Four");
        obtainedList.add("Five");
    }

    @Override
    public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {


       if(column == 0) {
           model.removeAllElements();
           for(int i = 0; i < obtainedList.size(); i++) {
               model.addElement(obtainedList.get(i));
            } 
        } else {

             model.removeAllElements();
             String selectedItem = (String) table.getValueAt(row, 0);
             for(int i = 0; i < obtainedList.size(); i++) {
                    if(!selectedItem.equals(obtainedList.get(i)))
                    model.addElement(obtainedList.get(i));
             } 
         } // Close else

        return super.getTableCellEditorComponent(table, value, isSelected, row, column);
     }
    }

回答2:

Try something like this, you can change DATA in this example, and repaint and do the Renderer of the cell:

 public void example(){  

      TableColumn tmpColum =table.getColumnModel().getColumn(1);
      String[] DATA = { "Data 1", "Data 2", "Data 3", "Data 4" };
      JComboBox comboBox = new JComboBox(DATA);

      DefaultCellEditor defaultCellEditor=new DefaultCellEditor(comboBox);
      tmpColum.setCellEditor(defaultCellEditor);
      tmpColum.setCellRenderer(new CheckBoxCellRenderer(comboBox));
      table.repaint();
   }


/**
   Custom class for adding elements in the JComboBox.
*/
class CheckBoxCellRenderer implements TableCellRenderer {
        JComboBox combo;
        public CheckBoxCellRenderer(JComboBox comboBox) {
            this.combo = new JComboBox();
            for (int i=0; i<comboBox.getItemCount(); i++){
                combo.addItem(comboBox.getItemAt(i));
            }
        }
        public Component getTableCellRendererComponent(JTable jtable, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            combo.setSelectedItem(value);
            return combo;
        }
    }

回答3:

After removeAllItems() call, add items in combobox as

  combobox.addItem("one");
  combobox.addItem("two");

来源：https://stackoverflow.com/questions/15272104/dynamic-jcombobox-items-inside-jtable