当单元格内的 JComboBox 中存在 ItemEvent 时，如何获取 CellRow [英] How do I get the CellRow when there is an ItemEvent in the JComboBox within the cell

问题描述

我有一个 JTable，其中有一列包含 JComboBox.

I have a JTable with a column containing a JComboBox.

我有一个附加到 JComboBox 的 ItemListener，它对任何更改起作用.

I have an ItemListener attached to the JComboBox which acts upon any changes.

但是，ItemListener 没有获取更改后的 ComboBox 所在行的方法.

However, ItemListener does not have a method for obtaining the Row that the changed ComboBox is within.

当 ComboBox 发生变化时，我需要行号以便对同一行中的另一列进行操作.

I need to Row number in order to act upon another column in the same row when the ComboBox has a change.

任何帮助将不胜感激.

这是我的简短代码.我想要完成的是在 itemlistener 获取更改时获取 ComboBox 的表格行.

This is my Short and Concise code. What I am trying to accomplish, is obtaining the Table Row of the ComboBox when a the itemlistener picks up a change.

import java.awt.*;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.io.IOException;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;

public class Example extends JFrame {

    private static final long serialVersionUID = 1L;
    public static int maxX, maxY;
    public static final String[] columnHeads = {"Col 1", "Col 2", "Col 3"};

    public static void main(String args[]) throws IOException {
        Example example = new Example();
    }

    public Example() {
        //Create Table Model
        DefaultTableModel model = new DefaultTableModel();

        for (int index = 0; index < columnHeads.length; index++) {
            model.addColumn(columnHeads[index]);
        }

        //Create Table
        JTable table = new JTable(model);
        JScrollPane scrollPane = new JScrollPane(table);

        //List for ComboBox
        String[] list = {"Item1", "Item2", "Item3"};

        //Create ComboBox
        JComboBox itemTypes = attachComboBoxRenderer(table, 2, list);

        //Attach Item Listener
        itemTypes.addItemListener(new ComboBoxListener());
        ((DefaultTableModel) table.getModel()).insertRow(
            table.getRowCount(), new Object[]{"C1", "C2", ""});
        this.setTitle("Example");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container container = getContentPane();

        //MAIN Panel
        final JPanel main = new JPanel();
        main.setLayout(new GridBagLayout());
        main.add(scrollPane);

        container.add(main);
        this.pack();
        this.setVisible(true);
    }

    public static JComboBox attachComboBoxRenderer(
        JTable table, int column, Object[] values) {
        JComboBox combo = new JComboBox(values);
        TableColumn col = table.getColumnModel().getColumn(column);
        col.setCellRenderer(new ComboBoxRenderer(values));
        col.setCellEditor(new DefaultCellEditor(combo));
        return combo;
    }
}

class ComboBoxListener implements ItemListener {

    private static final int SELECTED = 1;

    @Override
    public void itemStateChanged(ItemEvent e) {
        // Get the affected item
        Object item = e.getItem();
        if (item.toString() != null
            && !"".equals(item.toString())
            && e.getStateChange() == SELECTED) {
            System.out.println(item.toString() + " selected");
            //How do I get Row in the Table of the ComboBox that was changed?
        }
    }
}

class ComboBoxRenderer extends JComboBox implements TableCellRenderer {

    private static final long serialVersionUID = 1L;

    public ComboBoxRenderer(Object[] items) {
        super(items);
    }

    @Override
    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;
    }
}

推荐答案

听起来你是 使用组合框作为编辑器.如果是这样，TableCellEditor 方法，getTableCellEditorComponent()，包括行 作为参数.此处有一个相关示例.

It sounds like you are Using a Combo Box as an Editor. If so, the TableCellEditor method, getTableCellEditorComponent(), includes the row as a parameter. There's a related example here.

附录:要更改您编辑的同一行中的值，只需让模型根据该行中的相关值返回其他列"的正确值.或者，在触发更新之前更新模型的 setValueAt() 方法中的相关值，如 示例.

Addendum: To change a value in the same row you've edited, just have the model return the correct value for the "other column" based on the related values in that row. Alternatively, update the related value in your model's setValueAt() method before firing the update, as shown in the example.

附录:根据您的示例，以下代码覆盖模型的 getValueAt() 方法，以保持依赖列与项目列同步.

Addendum: Based on your example, the code below overrides the model's getValueAt() method to keep the dependent column synchronized with the item column.

import java.awt.*;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.io.IOException;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;

/** @see http://stackoverflow.com/questions/7350445 */
public class DependentColumn extends JFrame {

    private static final int DEPENDENT_COL = 1;
    private static final int ITEM_COL = 2;
    private static final String[] columnNames = {"Col 1", "Col 2", "Col 3"};

    public static void main(String args[]) throws IOException {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                DependentColumn dc = new DependentColumn();
            }
        });
    }

    public DependentColumn() {
        this.setTitle("Example");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create Model & Table
        DefaultTableModel model = new DefaultTableModel(columnNames, 0) {

            @Override
            public Object getValueAt(int row, int col) {
                if (col == DEPENDENT_COL) {
                    return "C2:" + this.getValueAt(row, ITEM_COL);
                } else {
                    return super.getValueAt(row, col);
                }
            }
        };
        for (int i = 0; i < 16; i++) {
            model.addRow(new Object[]{"C1", "C2", "Item1"});
        }
        JTable table = new JTable(model);
        table.setPreferredScrollableViewportSize(new Dimension(320, 120));

        //Create ComboBox
        String[] items = {"Item1", "Item2", "Item3"};
        JComboBox combo = new JComboBox(items);
        TableColumn col = table.getColumnModel().getColumn(ITEM_COL);
        col.setCellEditor(new DefaultCellEditor(combo));
        combo.addItemListener(new ItemListener() {

            @Override
            public void itemStateChanged(ItemEvent e) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    System.out.println(e.getItem() + " selected");
                }
            }
        });

        this.add(new JScrollPane(table));
        this.pack();
        this.setLocationRelativeTo(null);
        this.setVisible(true);
    }
}

这篇关于当单元格内的 JComboBox 中存在 ItemEvent 时，如何获取 CellRow的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！