java - JTable 中 JCombobox 的 setSelectedItem

Question

我有一个 JTable，我将三个 JComboBox 添加到三个不同的列。现在我想为我的每一行设置所选项目。问题是，我需要每一行的 ID 才能做到这一点。所以我尝试了不同的监听器，最好的结果是使用 FocusListener，但是我总是必须先单击该行，然后单击 JComboBox，这很费力。这是一个例子:

JTable table = new JTable();
    Vector<ArrayList<Object>> data = new Vector<ArrayList<Object>>();
    for (int i = 0; i < 5; i++)
    {
        ArrayList<Object> object = new ArrayList<Object>();
        object.add(i);
        object.add("name");
        object.add(i+1);
        object.add(i+1);
        object.add(i+1);
        data.add(object);
    }
    DefaultTableModel tableModel = new DefaultTableModel() {
        /**
         * 
         */
        private static final long serialVersionUID = 1L;

        @Override
        public boolean isCellEditable(int row, int column) {
            if (column < 2)
                return false;
            return true;
        }
    };
    tableModel.setColumnIdentifiers(new String[] {"ID", "Name", "OK", "Other", "Error"});
    tableModel.addTableModelListener(new TableModelListener()
    {

        @Override
        public void tableChanged(TableModelEvent e)
        {
            if (e.getType() == TableModelEvent.UPDATE)
            {
                int row = e.getFirstRow();
                int column = e.getColumn();
                TableModel table_model = (TableModel) e.getSource();
                ArrayList<Object> changed_data = (ArrayList<Object>) table_model.getValueAt(row, column);
                String row_id = String.valueOf(table_model.getValueAt(row, 0));
                for (ArrayList<Object> list : data)
                {
                    String compare_id = String.valueOf(list.get(0));
                    if (row_id.equals(compare_id))
                    {
                        list.set(column, String.valueOf(changed_data.get(0)));
                        for (int i = table_model.getRowCount()-1; i >= 0 ; i--)
                        {
                            tableModel.removeRow(i);
                        }

                        for (ArrayList<Object> object : data)
                        {
                            Vector<String> vector = new Vector<String>();
                            vector.addElement(String.valueOf(object.get(0)));
                            vector.addElement(String.valueOf(object.get(1)));
                            vector.addElement(String.valueOf(object.get(2)));
                            vector.addElement(String.valueOf(object.get(3)));
                            vector.addElement(String.valueOf(object.get(4)));
                            tableModel.addRow(vector);
                        }

                        TableColumn column_ok = table.getColumnModel().getColumn(2);
                        TableColumn column_other = table.getColumnModel().getColumn(3);
                        TableColumn column_error = table.getColumnModel().getColumn(4);

                        JComboBox<ArrayList<Object>> combobox_ok = new JComboBox<ArrayList<Object>>(data);
                        JComboBox<ArrayList<Object>> combobox_other = new JComboBox<ArrayList<Object>>(data);
                        JComboBox<ArrayList<Object>> combobox_error = new JComboBox<ArrayList<Object>>(data);

                        column_ok.setCellEditor(new DefaultCellEditor(combobox_ok));
                        column_other.setCellEditor(new DefaultCellEditor(combobox_other));
                        column_error.setCellEditor(new DefaultCellEditor(combobox_error));
                        break;
                    }
                }
            }
        }
    });
    table.setModel(tableModel);
    for (ArrayList<Object> object : data)
    {
        Vector<String> vector = new Vector<String>();
        vector.addElement(String.valueOf(object.get(0)));
        vector.addElement(String.valueOf(object.get(1)));
        vector.addElement(String.valueOf(object.get(2)));
        vector.addElement(String.valueOf(object.get(3)));
        vector.addElement(String.valueOf(object.get(4)));
        tableModel.addRow(vector);
    }

    TableColumn column_ok = table.getColumnModel().getColumn(2);
    TableColumn column_other = table.getColumnModel().getColumn(3);
    TableColumn column_error = table.getColumnModel().getColumn(4);

    JComboBox<ArrayList<Object>> combobox_ok = new JComboBox<ArrayList<Object>>(data);
    JComboBox<ArrayList<Object>> combobox_other = new JComboBox<ArrayList<Object>>(data);
    JComboBox<ArrayList<Object>> combobox_error = new JComboBox<ArrayList<Object>>(data);

    column_ok.setCellEditor(new DefaultCellEditor(combobox_ok));
    column_other.setCellEditor(new DefaultCellEditor(combobox_other));
    column_error.setCellEditor(new DefaultCellEditor(combobox_error));

    JScrollPane scrollPane = new JScrollPane();
    scrollPane.getViewport().add(table);

    JFrame frame = new JFrame();
    frame.add(scrollPane);
    frame.setSize(400, 200);
    frame.setVisible(true);

现在，在第一行第三列(“确定”)中，您可以在 JComboBox 中选择代表一行的不同条目。因此一行有三个引用另一行的 JComboBox。如果您单击此类 JComboBox，您会注意到它始终选择第一个条目，而不是您在单击之前看到的编号的条目。

也许现在你明白我想做什么了？

Answer 1

If you click in such a JComboBox, you will notice it always chooses the first entry and not the entry with the number you saw before clicking at it.

重点关注问题的这方面，以下简化、完整的示例始终在单元格编辑器处于 Activity 状态时显示选定的条目。您可以替换组合的 default renderer根据需要显示不同的结果。此外，

• 重写getPreferredScrollableViewportSize()以建立所需的表格大小。

• 尽可能使用类型参数；根据需要重写 getColumnClass()，对于 example .

• 重写getValueAt()，如图here和 here ，用于相关数据。

• 请注意下面 isCellEditable() 的简化实现。

import java.awt.Dimension;
import java.awt.EventQueue;
import java.util.Arrays;
import java.util.Vector;
import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;

/**
 * @see https://stackoverflow.com/q/39993746/230513
 */
public class TableComboTest {

    private Vector<Vector<String>> createData() {
        Vector<Vector<String>> data = new Vector<Vector<String>>();
        for (int i = 0; i < 5; i++) {
            Vector<String> rowVector = new Vector<String>();
            rowVector.add(String.valueOf(i));
            rowVector.add("name");
            rowVector.add(String.valueOf(i + 1));
            rowVector.add(String.valueOf(i + 1));
            rowVector.add(String.valueOf(i + 1));
            data.add(rowVector);
        }
        return data;
    }

    private void display() {
        Vector<Vector<String>> data = createData();
        Vector<String> names = new Vector<>(Arrays.asList("ID", "Name", "OK", "Other", "Error"));
        DefaultTableModel tableModel = new DefaultTableModel(data, names) {

            @Override
            public boolean isCellEditable(int row, int column) {
                return column > 1;
            }
        };
        JTable table = new JTable(tableModel) {
            @Override
            public Dimension getPreferredScrollableViewportSize() {
                return new Dimension(getPreferredSize().width, getRowHeight() * 4);
            }
        };

        TableColumn column_ok = table.getColumnModel().getColumn(2);
        TableColumn column_other = table.getColumnModel().getColumn(3);
        TableColumn column_error = table.getColumnModel().getColumn(4);

        String[] choices = new String[]{"1", "2", "3", "4", "5"};
        JComboBox<String> combobox_ok = new JComboBox<>(choices);
        JComboBox<String> combobox_other = new JComboBox<String>(choices);
        JComboBox<String> combobox_error = new JComboBox<String>(choices);

        column_ok.setCellEditor(new DefaultCellEditor(combobox_ok));
        column_other.setCellEditor(new DefaultCellEditor(combobox_other));
        column_error.setCellEditor(new DefaultCellEditor(combobox_error));

        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new JScrollPane(table));
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new TableComboTest()::display);
    }
}