java - JTable 的实时排序

Question

我已经想出如何让 JTable 正确排序，但我想不出如何让它在表格单元格更改时自动更新排序顺序。现在，我有这段(诚然很长)代码，主要基于 Java 教程的 How to Use Tables 中的代码。 .我用 //ADDED 突出显示了我所做的更改。在这种情况下，新添加的值可以正确排序，但是当我进入编辑一个值时，它似乎并没有求助，即使我调用了 fireTableCellUpdated?

简而言之，当模型中的数据值发生变化时，如何让表格重新排序？

/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 * See the standard BSD license.
 */ 

package components;

/*
 * TableSortDemo.java requires no other files.
 */

import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;

public class TableSortDemo extends JPanel {
    private boolean DEBUG = false;

    public TableSortDemo() {
        super();
        setLayout(new BoxLayout(TableSortDemo.this, BoxLayout.PAGE_AXIS));
        final MyTableModel m = new MyTableModel();
        JTable table = new JTable(m);
        table.setPreferredScrollableViewportSize(new Dimension(500, 70));
        table.setFillsViewportHeight(true);
        table.setAutoCreateRowSorter(true);

        //Create the scroll pane and add the table to it.
        JScrollPane scrollPane = new JScrollPane(table);

        //Add the scroll pane to this panel.
        add(scrollPane);

        // ADDED: button to add a value
        JButton addButton = new JButton("Add a new value");
        addButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                m.addValue(
                        JOptionPane.showInputDialog(
                                TableSortDemo.this, "Value?"));
            }
        });

        // ADDED button to change a value
        JButton setButton = new JButton("Change a value");
        setButton.addActionListener(new ActionListener() {
            /* (non-Javadoc)
             * @see java.awt.event.ActionListener#actionPerformed(java.awt.event.ActionEvent)
             */
            public void actionPerformed(ActionEvent e) {
                m.setValueAt(
                        JOptionPane.showInputDialog(
                                TableSortDemo.this, "Value?"),
                        Integer.parseInt(
                                JOptionPane.showInputDialog(
                                        TableSortDemo.this, "Which?")), 0);
            }
        });
        add(addButton);
        add(setButton);
    }

    class MyTableModel extends AbstractTableModel {
        private static final long serialVersionUID = -7053335255134714625L;
        private String[] columnNames = {"Column"};
        // ADDED data as mutable ArrayList
        private ArrayList<String> data = new ArrayList<String>();

        public MyTableModel() {
            data.add("Anders");
            data.add("Lars");
            data.add("Betty");
            data.add("Anna");
            data.add("Jon");
            data.add("Zach");
        }

        // ADDED
        public void addValue(Object v) {
            data.add(v.toString());
            int row = data.size() - 1;
            fireTableRowsInserted(row, row);
        }

        public int getColumnCount() {
            return columnNames.length;
        }

        public int getRowCount() {
            return data.size();
        }

        public String getColumnName(int col) {
            return columnNames[col];
        }

        public Object getValueAt(int row, int col) {
            return data.get(row) + " " + row;
        }

        /*
         * JTable uses this method to determine the default renderer/
         * editor for each cell.  If we didn't implement this method,
         * then the last column would contain text ("true"/"false"),
         * rather than a check box.
         */
        public Class<String> getColumnClass(int c) {
            return String.class;
        }

        /*
         * Don't need to implement this method unless your table's
         * editable.
         */
        public boolean isCellEditable(int row, int col) {
            //Note that the data/cell address is constant,
            //no matter where the cell appears onscreen.
            if (col < 2) {
                return false;
            } else {
                return true;
            }
        }

        /*
         * Don't need to implement this method unless your table's
         * data can change.
         */
        public void setValueAt(Object value, int row, int col) {
            if (DEBUG) {
                System.out.println("Setting value at " + row + "," + col
                                   + " to " + value
                                   + " (an instance of "
                                   + value.getClass() + ")");
            }

            data.set(row, value.toString());

            // ADDED: uncommented this line, despite warnings to the contrary
            fireTableCellUpdated(row, col);

            if (DEBUG) {
                System.out.println("New value of data:");
                printDebugData();
            }
        }

        private void printDebugData() {
            int numRows = getRowCount();
            int numCols = getColumnCount();

            for (int i=0; i < numRows; i++) {
                System.out.print("    row " + i + ":");
                for (int j=0; j < numCols; j++) {
                    System.out.print("  " + data.get(i));
                }
                System.out.println();
            }
            System.out.println("--------------------------");
        }
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("TableSortDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        TableSortDemo newContentPane = new TableSortDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

Answer 1

这采取了两步解决方案:

首先，我使用 TableSorter 对数据更改进行排序，而不是 autoCreateRowSorter:

sorter = new TableRowSorter<MyTableModel>(m);
table.setRowSorter(sorter);
sorter.setSortsOnUpdates(true);

然后，我不得不更改更新方法以更新整个表。 fireTableCellUpdated 和 fireTableRowsUpdated 只会重绘更新的特定行，而不是整个表(这意味着您会得到一个重复出现的条目，一旦它发生变化后来重绘了，所以，我改了

fireTableCellUpdated(row, col);

到

fireTableRowsUpdated(0, data.size() - 1);

现在它可以正确排序，即使数据发生变化，选择也会被保留。