JTable with Comparator 在排序后访问了错误的行数据；删除 getModel() 修复了它。为什么？

Question

为我的 JTable:

引入排序非常容易

  //Existing code
  dftTableModel = new DefaultTableModel(0 , 4);
  tblOutput     = new JTable(dftTableModel);

  //Added code
  RowSorter<TableModel> sorter = new TableRowSorter<TableModel>(dftTableModel);
  tblOutput.setRowSorter(sorter);

但是由于我将 Size 列格式化为带逗号的文本，所以它没有排序：

我从未使用过 Comparator 但找到了一个我修改过的例子。

public class RowSorterWithComparator 
{
  static Comparator               compareNumericStringsWithCommas;
  static TableRowSorter           sorter;
  static JTable                   tblOutput;
  static JScrollPane              pane;
  static JFrame                   frame;
  static DefaultTableModel        dftTableModel; 
//  static TableColumnAdjuster      tca ;
  static DefaultTableCellRenderer rightRenderer;
  static JButton                  btnOpen;

  static String[] columnNames = { "Date", "Size" };
  static Object rows[][] = 
{
{"7/27/2015","96","mavenVersion.xml","C:\Users\Dov\.AndroidStudio1.2\config\options\"},
{"7/27/2015","120","keymap.xml","C:\Users\Dov\.AndroidStudio1.2\config\options\"},
{"7/27/2015","108","Default.xml","C:\Users\Dov\.AndroidStudio1.2\config\inspection\"},
{"4/27/2015","392","key pay.txt","C:\Users\Dov\A\"},
{"6/13/2015","161","BuildConfig.java","C:\Users\Dov\androidfp2_examples\eclipse_projects\FlagQuiz\gen\com\deitel\flagquiz\"}
};

  public static void main(String args[]) 
  {
    compareNumericStringsWithCommas = (Comparator) new Comparator() 
    {
      @Override public int compare(Object oo1, Object oo2) 
      {
        String o1 = oo1.toString().replace(",", "");
        String o2 = oo2.toString().replace(",", "");
        return Integer.valueOf(o1).compareTo(Integer.valueOf(o2));
      }
    };

    dftTableModel = new DefaultTableModel(0 , columnNames.length);
    tblOutput     = new JTable(dftTableModel);
    dftTableModel.setColumnIdentifiers(new Object[]{"Date", "Size", "File name", "Path to file"});

    rightRenderer = new DefaultTableCellRenderer();
    rightRenderer.setHorizontalAlignment(SwingConstants.RIGHT);
    tblOutput.getColumnModel().getColumn(1).setCellRenderer(rightRenderer);

    sorter      = new TableRowSorter<>(dftTableModel);
    sorter.setModel(tblOutput.getModel());
    sorter.setComparator(1,compareNumericStringsWithCommas);

    tblOutput.setRowSorter(sorter);
    tblOutput.setAutoResizeMode(AUTO_RESIZE_OFF);

//    tca = new tablecolumnadjuster.TableColumnAdjuster(tblOutput);
//    tca.setDynamicAdjustment(true);

    tblOutput.setFont(new Font("Courier New",Font.PLAIN,12));

    pane = new JScrollPane(tblOutput);

    for (int i = 0; i < 5; i++)
      dftTableModel.addRow(rows[i]);

    btnOpen = new JButton("Open selected file");

    btnOpen.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e)
        {       
          int row = tblOutput.getSelectedRow();
          String entry = (String)tblOutput.getModel().getValueAt(row, 3) 
                + "\" + (String)tblOutput.getModel().getValueAt(row, 2);
          try 
          {
            Desktop.getDesktop().open(new File((entry.trim())));
          } catch (IOException ex) {System.out.println("Can't open file"); }
      }
    });

    frame = new JFrame("Sort Table Demo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(pane, BorderLayout.CENTER);
    frame.add(btnOpen, BorderLayout.AFTER_LAST_LINE);
    frame.setSize(800, 350);
    frame.setVisible(true);
  }
}

效果很好。

将尺寸列右对齐很容易：

rightRenderer = new DefaultTableCellRenderer();
rightRenderer.setHorizontalAlignment(SwingConstants.RIGHT);

我添加了一个按钮来打开所选文件。但是排序后，打开了错误的文件。

所以我从鼠标侦听器中的语句中删除了getModel：

          String entry = (String)tblOutput.getValueAt(row, 3) 
                + "\" + (String)tblOutput.getValueAt(row, 2);

我不知道为什么它会在那里，因为我一直在偷来自不同地方的各种代码。

无论如何，现在一切正常。

但我有疑问：

(1) 在获取 table 行的值的上下文中什么时候需要 getModel？我想既然 dftTableModel 被用于 tblOutput 那肯定是正确的。

(2) getModel返回的行是数据原来所在的行吗？如果是这样，我想这有时会有用。不确定什么时候...到 "un-sort"?

(3) 是我用了 TableRowSorter 的原因 getModel 没有得到正确的数据？（即，两者不兼容吗？）

(4) dftTableModel是否等同于tblOutput.getModel()?

.....................

程序导入：

import java.awt.BorderLayout;
import java.awt.Desktop;
import java.awt.Font;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.File;
import java.io.IOException;
import java.util.Comparator;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import static javax.swing.JTable.AUTO_RESIZE_OFF;
import javax.swing.SwingConstants;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableRowSorter;
//import tablecolumnadjuster.TableColumnAdjuster;

Answer 1

So I removed getModel from the statement in the mouse listener:

TableModel 中的数据未排序。 View (JTable) 以排序的顺序显示数据

您使用以下方法从视图中获取数据：

table.getValueAt(row, column);

如果您想从您使用的 TableModel 中获取数据：

int modelRow = table.convertRpwIndexToModel(row);
table.getModel().getValueAt(modelRow, column);

还有列索引来回转换的方法。

所以你总是需要知道你是试图访问数据在 JTable 上显示的方式还是加载到 TableModel 的方式，然后使用适当的索引这可能（或可能）不涉及索引转换。

String entry = (String)tblOutput.getValueAt(row, 3) ...

当您对值进行硬编码时，您需要知道硬编码值代表什么。在这种情况下，您正在访问来自 table 的动态行值和来自模型的列。

因此在上面的语句中，您需要将“3”从模型转换为视图，因为您使用的是 table 的 getValueAt(...) 方法。

int viewColumn3 = table.convertColumnIndexToView(3);
String entry = (String)tblOutput.getValueAt(row, viewColumn3)

或者，由于您多次引用硬编码值（即第 2 列和第 3 列），因此保留硬编码列索引并仅转换一次行索引然后从 TableModel 访问数据可能更容易：

String entry = (String)tblOutput.getModel().getValueAt(modelRow, 3) ...

Answer 2

这现在是一个 SSCCE（见评论），但它是根据@camickr 上下评论中的建议对原始代码进行的修订。

此问题已修复目前，拖动列后，如果文件名或路径列位置发生变化，单击按钮会导致错误，例如The file: xml\C:\Users\Dov\.AndroidStudio1.2\config\options doesn't exist.这发生在之后将扩展列（在文件名列之前）移动到路径列之后。

import java.awt.BorderLayout;
import java.awt.Desktop;
import java.awt.Font;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.File;
import java.io.IOException;
import java.util.Comparator;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import static javax.swing.JTable.AUTO_RESIZE_OFF;
import javax.swing.SwingConstants;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableRowSorter;
//import tablecolumnadjuster.TableColumnAdjuster;

public class RowSorterWithComparator 
{
  static final int    DATE_COLUMN     = 0;
  static final int    SIZE_COLUMN     = 1;
  static final int    EXTENSION_COLUMN= 2;
  static final int    FILENAME_COLUMN = 3;
  static final int    PATH_COLUMN     = 4;

  public static void main(String args[]) 
  {
    Comparator               compareNumericStringsWithCommas;
    TableRowSorter           sorter;
    JTable                   tblOutput;
    JScrollPane              pane;
    JFrame                   frame;
    DefaultTableModel        dftTableModel; 
//    TableColumnAdjuster      tca ;
    DefaultTableCellRenderer rightRenderer;
    JButton                  btnOpen;

    Object[] columnNames = new Object[]{"Date", "Size", "Extension", "File name", "Path to file"};
    Object rows[][] = 
      {
      {"7/27/2015","9,600","xml","mavenVersion.xml","C:/Users/Dov/.AndroidStudio1.2/config/options/"},
      {"7/27/2015","120,000","xml","keymap.xml","C:/Users/Dov/.AndroidStudio1.2/config/options/"},
      {"7/27/2015","108","xml","Default.xml","C:/Users/Dov/.AndroidStudio1.2/config/inspection/"},
      {"4/27/2015","39,200","txt","key pay.txt","C:/Users/Dov/A/"},
      {"6/13/2015","91","java","BuildConfig.java","C:/Users/Dov/androidfp2_examples/eclipse_projects/FlagQuiz/gen/com/deitel/flagquiz/"}
      };

    compareNumericStringsWithCommas = (Comparator) new Comparator() 
    {
      @Override public int compare(Object oo1, Object oo2) 
      {
        String o1 = oo1.toString().replace(",", "");
        String o2 = oo2.toString().replace(",", "");
        return Integer.valueOf(o1).compareTo(Integer.valueOf(o2));
      }
    };

    dftTableModel = new DefaultTableModel(0 , columnNames.length);
    tblOutput     = new JTable(dftTableModel);
    dftTableModel.setColumnIdentifiers(columnNames);

    rightRenderer = new DefaultTableCellRenderer();
    rightRenderer.setHorizontalAlignment(SwingConstants.RIGHT);
    tblOutput.getColumnModel().getColumn(1).setCellRenderer(rightRenderer);

    sorter      = new TableRowSorter<>(dftTableModel);
    sorter.setModel(tblOutput.getModel());
    sorter.setComparator(1,compareNumericStringsWithCommas);

    tblOutput.setRowSorter(sorter);
    tblOutput.setAutoResizeMode(AUTO_RESIZE_OFF);

    //    tca = new tablecolumnadjuster.TableColumnAdjuster(tblOutput);
    //    tca.setDynamicAdjustment(true);

    tblOutput.setFont(new Font("Courier New",Font.PLAIN,12));

    pane = new JScrollPane(tblOutput);

    for (Object[] row : rows)
      dftTableModel.addRow(row);

    btnOpen = new JButton("Open selected file");

    btnOpen.addMouseListener(new MouseAdapter() 
    {
        @Override
        public void mouseClicked(MouseEvent e)
        {       
          int viewFilenameCol = tblOutput.convertColumnIndexToView(FILENAME_COLUMN);
          int viewPathCol     = tblOutput.convertColumnIndexToView(PATH_COLUMN);
          int row = tblOutput.getSelectedRow();
          String entry = (String)tblOutput.getValueAt(row, viewPathCol) 
                      +  (String)tblOutput.getValueAt(row, viewFilenameCol);
          try 
          {
            Desktop.getDesktop().open(new File((entry.trim())));
          } 
          catch 
          (
            Exception ex) {System.out.println("Can't open file <" + entry + ">"); 
          }
      }
    });

    frame = new JFrame("Sort Table Demo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(pane, BorderLayout.CENTER);
    frame.add(btnOpen, BorderLayout.SOUTH);
    frame.setSize(800, 350);
    frame.setVisible(true);
  }
}

JTable with Comparator 在排序后访问了错误的行数据；删除 getModel() 修复了它。为什么？

JTable with Comparator accessed wrong row data after sort; removing getModel() fixed it. Why?

java

swing

jtable

comparator