如何在 JTable 中的级联 JCombobox 选项中进行选择？

Question

我有一个 JTable，数字 1,2,3 作为第一列，数字作为第二列中的文本，可以使用 JCombobox 进行选择。 例如，1 可以在第 2 列中表示为“1”、ONE、FIRST 或 ONCE。 当我做出选择时，下面行的所有组合框都必须使用相同性质的文本进行级联更新。 因此，如果我选择 ONCE，则下面各行的组合框应更新为 TWICE、THRICE。 如果我选择 FIRST，下面各行的组合框应更新为 SECOND、THIRD。 等等..

起初它看起来像是在工作，但每当我点击 JTable 上的其他位置时，combobox 就会更新为最后一行的值。 例如，如果我在第一行选择 ONCE，首先它会将其他行更新为 TWICE 和 THRICE。 然后，如果我单击任何一行，combobox 选择将在第一行更新为 THRICE。 下次单击时，第二行将更新为 THRICE。

我在这里做错了什么？

combobox 单元格编辑器：

public class NumberChoiceEditor extends DefaultCellEditor {

    private static final long serialVersionUID = 1L;

    private String numberAsText;

    private static final String[][] NUMBERS = { { "1", "ONE", "FIRST", "ONCE" }, { "2", "TWO", "SECOND", "TWICE" }, { "3", "THREE", "THIRD", "THRICE" } };

    public NumberChoiceEditor() {
        super(new JComboBox<>());
    }

    @Override
    public Object getCellEditorValue() {
        return numberAsText;
    }

    @Override
    public Component getTableCellEditorComponent(final JTable table, final Object value, final boolean isSelected, final int row, final int column) {
        if (value instanceof String) {
            numberAsText = (String) value;
        }
        JComboBox<String> numberTextChoice = new JComboBox<>(NUMBERS[row]);
        numberTextChoice.setSelectedItem(numberAsText);
        numberTextChoice.addActionListener(e -> {
            numberAsText = (String) numberTextChoice.getSelectedItem();
            int nextRow = row + 1;
            if (nextRow < NUMBERS.length) {
                String numberText = (String) table.getValueAt(nextRow, 1);
                JComboBox<String> nextRowChoices = (JComboBox<String>) getTableCellEditorComponent(table, numberText, isSelected, nextRow, column);
                nextRowChoices.setSelectedIndex(numberTextChoice.getSelectedIndex());
                table.setValueAt(nextRowChoices.getSelectedItem(), nextRow, 1);
            }
        });
        return numberTextChoice;
    }

}

主要class配车架：

public class NumberTable {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            JTable table = new JTable(new Object[][] { { 1, "1" }, { 2, "2" }, { 3, "3" } }, new Object[] { "Number", "Number Text" });
            table.getColumn("Number Text").setCellEditor(new NumberChoiceEditor());
            table.setRowHeight(25);
            JFrame frame = new JFrame("Number Table");
            frame.add(new JScrollPane(table));
            frame.setLocationRelativeTo(null);
            frame.setSize(600, 200);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
        });
    }
}

Answer 1

我会使用TableModelListener 。 当通过JComboBox编辑器更改值时，我会相应地调整TableModel 。

（代码后的注释。）

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;

import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;

public class NumTable implements Runnable, TableModelListener {
    private boolean  adjusting;
    private JFrame  frame;
    private JTable  table;

    @Override
    public void run() {
        createGui();
    }

    @Override
    public void tableChanged(TableModelEvent event) {
        if (!adjusting) {
            adjusting = true;
            int col = event.getColumn();
            if (col == 1) {
                NumChoiceEd editor = (NumChoiceEd) table.getColumnModel().getColumn(1).getCellEditor();
                int row = event.getFirstRow();
                JComboBox<String> combo = editor.getCombo(row);
                if (combo != null) {
                    int ndx = combo.getSelectedIndex();
                    if (ndx >= 0) {
                        int rows = table.getRowCount();
                        for (int i = 0; i < rows; i++) {
                            combo = editor.getCombo(i);
                            String val = combo.getModel().getElementAt(ndx);
                            table.setValueAt(val, i, col);
                        }
                    }
                }
            }
            adjusting = false;
        }
    }

    private void createGui() {
        frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(createTable(), BorderLayout.CENTER);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private JScrollPane createTable() {
        Object[][] data = new Object[][]{{1, "1"}, {2, "2"}, {3, "3"}};
        Object[] columnNames = new Object[]{"Number", "Number Text"};
        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        model.addTableModelListener(this);
        table = new JTable(model);
        table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
        TableColumnModel tcm = table.getColumnModel();
        TableColumn column = tcm.getColumn(1);
        column.setCellEditor(new NumChoiceEd());
        JScrollPane scrollPane = new JScrollPane(table);
        return scrollPane;
    }

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

class NumChoiceEd extends DefaultCellEditor {
    private static final long serialVersionUID = 1L;
    private JComboBox<String>  oneCombo;
    private JComboBox<String>  twoCombo;
    private JComboBox<String>  threeCombo;

    public NumChoiceEd() {
        super(new JComboBox<>());
        oneCombo = new JComboBox<>(new String[]{"1", "ONE", "FIRST", "ONCE"});
        twoCombo = new JComboBox<>(new String[]{"2", "TWO", "SECOND", "TWICE"});
        threeCombo = new JComboBox<>(new String[]{"3", "THREE", "THIRD", "THRICE"});
    }

    public JComboBox<String> getCombo(int row) {
        switch (row) {
            case 0:
                return oneCombo;
            case 1:
                return twoCombo;
            case 2:
                return threeCombo;
            default:
                return null;
        }
    }

    @Override
    public Component getTableCellEditorComponent(final JTable table,
                                                 final Object value,
                                                 final boolean isSelected,
                                                 final int row,
                                                 final int column) {
        if (column == 1) {
            switch (row) {
                case 0:
                    return oneCombo;
                case 1:
                    return twoCombo;
                case 2:
                    return threeCombo;
                default:
                    return super.getTableCellEditorComponent(table, value, isSelected, row, column);
            }
        }
        else {
            return super.getTableCellEditorComponent(table, value, isSelected, row, column);
        }
    }
}

我不是在每次调用getTableCellEditorComponent方法时都创建一个新的JComboBox ，而是首先创建所有三个JComboBox并返回相关的一个。
您不需要重写方法getCellEditorValue因为超类方法（在 class DefaultCellEditor中）将返回正确的值。
一旦用户更改了值（并关闭了表格单元格编辑器），就会调用方法tableChanged 。 In that method, I get the index of the value that was selected from the JComboBox and then I go through all the rows in the JTable and get the value at that index in the JComboBox for each row and set the JTable value to that value.
因为我在方法tableChanged中更改了TableModel ，这将导致该方法再次被调用。 为了防止递归调用，我使用了adjusting标志。

在下面的屏幕截图中，我从JComboBox中选择了一个值，但我还没有关闭编辑器。 如果我导航到JTable中的另一个单元格，它将关闭编辑器，然后所有显示的数据都会改变。 请注意，如果您导航到不同行中的Number Text列，您可能看不到更改，因为这将立即打开您导航到的单元格的JComboBox编辑器。

关闭编辑器后，表格如下面的屏幕截图所示。

请注意，上述屏幕截图中有很多空白区域，因为JTable的默认尺寸非常大，但显示数据所需的空间（在这种情况下）很小。 使JTable更小（在这种情况下）的一种方法是更改JScrollPane的首选大小。

编辑

针对您在评论中提出的问题，即

是否可以更新 combobox 值更改

对的，这是可能的。 您向每个JComboBox添加一个ActionListener ，它只调用方法stopCellEditing 。 这是上面的代码，修改为包含ActionListener 。 唯一的变化是 class NumChoiceEd 。

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.event.ActionListener;

import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;

public class NumTable implements Runnable, TableModelListener {
    private boolean  adjusting;
    private JFrame  frame;
    private JTable  table;

    @Override
    public void run() {
        createGui();
    }

    @Override
    public void tableChanged(TableModelEvent event) {
        if (!adjusting) {
            adjusting = true;
            int col = event.getColumn();
            if (col == 1) {
                NumChoiceEd editor = (NumChoiceEd) table.getColumnModel().getColumn(1).getCellEditor();
                int row = event.getFirstRow();
                JComboBox<String> combo = editor.getCombo(row);
                if (combo != null) {
                    int ndx = combo.getSelectedIndex();
                    if (ndx >= 0) {
                        int rows = table.getRowCount();
                        for (int i = 0; i < rows; i++) {
                            combo = editor.getCombo(i);
                            String val = combo.getModel().getElementAt(ndx);
                            table.setValueAt(val, i, col);
                        }
                    }
                }
            }
            adjusting = false;
        }
    }

    private void createGui() {
        frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(createTable(), BorderLayout.CENTER);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private JScrollPane createTable() {
        Object[][] data = new Object[][]{{1, "1"}, {2, "2"}, {3, "3"}};
        Object[] columnNames = new Object[]{"Number", "Number Text"};
        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        model.addTableModelListener(this);
        table = new JTable(model);
        table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
        TableColumnModel tcm = table.getColumnModel();
        TableColumn column = tcm.getColumn(1);
        column.setCellEditor(new NumChoiceEd());
        JScrollPane scrollPane = new JScrollPane(table);
        return scrollPane;
    }

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

class NumChoiceEd extends DefaultCellEditor {
    private static final long serialVersionUID = 1L;
    private JComboBox<String>  oneCombo;
    private JComboBox<String>  twoCombo;
    private JComboBox<String>  threeCombo;

    public NumChoiceEd() {
        super(new JComboBox<>());
        ActionListener al = event -> NumChoiceEd.this.stopCellEditing(); // ADDED THIS LINE
        oneCombo = new JComboBox<>(new String[]{"1", "ONE", "FIRST", "ONCE"});
        oneCombo.addActionListener(al); // ADDED THIS LINE
        twoCombo = new JComboBox<>(new String[]{"2", "TWO", "SECOND", "TWICE"});
        twoCombo.addActionListener(al); // ADDED THIS LINE
        threeCombo = new JComboBox<>(new String[]{"3", "THREE", "THIRD", "THRICE"});
        threeCombo.addActionListener(al); // ADDED THIS LINE
    }

    public JComboBox<String> getCombo(int row) {
        switch (row) {
            case 0:
                return oneCombo;
            case 1:
                return twoCombo;
            case 2:
                return threeCombo;
            default:
                return null;
        }
    }

    @Override
    public Component getTableCellEditorComponent(final JTable table,
                                                 final Object value,
                                                 final boolean isSelected,
                                                 final int row,
                                                 final int column) {
        if (column == 1) {
            switch (row) {
                case 0:
                    return oneCombo;
                case 1:
                    return twoCombo;
                case 2:
                    return threeCombo;
                default:
                    return super.getTableCellEditorComponent(table, value, isSelected, row, column);
            }
        }
        else {
            return super.getTableCellEditorComponent(table, value, isSelected, row, column);
        }
    }
}

如何在 JTable 中的级联 JCombobox 选项中进行选择？

问题描述

1 个解决方案

解决方案1
2 已采纳 2021-04-27 11:14:41

编辑

如何在 JTable 中的级联 JCombobox 选项中进行选择？

问题描述

1 个解决方案

解决方案1 2 已采纳 2021-04-27 11:14:41

编辑

解决方案1
2 已采纳 2021-04-27 11:14:41