【发布时间】：2018-05-08 20:44:00
【问题描述】：
在上一个问题 (Convert modelRowIndex to viewRowIndex for sorted JTable) 中，我指出我正在尝试创建一个“简单”JTable，它使用 TableModel 将 ArrayList 与使用 TableModel 的 JTable 联系起来。我的目标是——现在仍然是——保留所有 java 的内置 JTable 功能，这些功能允许单元格编辑、行排序和列重新排列。感谢您的帮助，该功能现在可以使用。
我现在正在尝试添加插入和删除表格行的功能。我在这里提供的（更新的）示例有效......除了......在特定的操作序列下，抛出“IndexOutOfBoundsException”。这是我的代码：
package tableexample;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.AbstractTableModel;
public final class TableExample extends JFrame {
List<REItem> REList;
JTable tblREList;
JButton btnAddInsertRE, btnDeleteRE;
JScrollPane spMain;
JFrame frame;
Container pane;
public TableExample() {
// create and populate the ArrayList
REList = new ArrayList<>();
REList.add(new REItem("Template1", "Comment1"));
REList.add(new REItem("Template2", "Comment2"));
RETableModel retm = new RETableModel(REList); // Connect the List to the TableModel
// create GUI components
frame = new JFrame ("Table Example");
btnAddInsertRE = new JButton("Add/Insert");
btnDeleteRE = new JButton("Delete");
tblREList = new JTable(retm);
tblREList.setAutoCreateRowSorter(true);
spMain = new JScrollPane(tblREList);
// add button ActionListeners
btnAddInsertRE.addActionListener((ActionEvent evt) -> { btnAddInsertREActionPerformed(evt); });
btnDeleteRE.addActionListener((ActionEvent evt) -> { btnDeleteREActionPerformed(evt); });
// place GUI components and make the GUI visible
pane = frame.getContentPane();
pane.setLayout (null);
pane.add(btnAddInsertRE);
pane.add(btnDeleteRE);
pane.add(spMain);
btnAddInsertRE.setBounds (10, 10, 100, 25);
btnDeleteRE.setBounds (120, 10, 100, 25);
spMain.setBounds (10, 45, spMain.getPreferredSize().width, spMain.getPreferredSize().height);
frame.setSize(spMain.getWidth() + 40, spMain.getHeight() + 95);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
} // end TableExample constructor
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
TableExample notUsed = new TableExample();
});
} //end main
private void btnAddInsertREActionPerformed(ActionEvent evt) {
// Add a FileSelection object to the ArrayList
int r = tblREList.getSelectedRow(); // get row selection, if any
if (r < 0) { // no row selected
REList.add(new REItem("NewTemplate", "NewComment")); // append new item to end
r = REList.size()-1; // get index to new item
} else { // else no row selected
REList.add(r, new REItem("NewTemplate", "NewComment")); // insert above selected row
} // row selected or not
spMain.setViewportView(tblREList); // repaint the updated table
tblREList.getSelectionModel().setSelectionInterval(r, r); // select the new row
}
private void btnDeleteREActionPerformed(ActionEvent evt) {
int[] selRows = tblREList.getSelectedRows(); // see if any rows are selected
if (selRows.length>0) { // at least one row is selected
for (int r=selRows.length-1; r>=0; r--) { // delete each row, from the bottom up,
REList.remove(r); // so that indexes are correct and
} // don't change with each delete
tblREList.clearSelection(); // clear the row selection data
spMain.setViewportView(tblREList); // repaint the updated table
} else { // else no row(s) selected
JOptionPane.showMessageDialog(null, "Must select at least one item to delete");
} // no row selected
} // end btnDeleteREActionPerformed
public final class REItem {
String template;
String comment;
public REItem(String tmp, String cmt) {
this.template = tmp;
this.comment = cmt;
}
} // end class REItem
public class RETableModel extends AbstractTableModel {
private List<REItem> reList = new ArrayList();
private final String[] columnNames = { "Template", "Comment" };
public RETableModel(List<REItem> list){
this.reList = list;
}
@Override
public String getColumnName(int column){
return columnNames[column];
}
@Override
public int getRowCount() {
return reList.size();
}
@Override
public int getColumnCount() {
return columnNames.length;
}
@Override
public Object getValueAt(int row, int column) {
switch (column) {
case 0: return reList.get(row).template;
case 1: return reList.get(row).comment;
}
return null; // default case
}
@Override
public boolean isCellEditable(int row, int column) {
return true;
}
@Override
public Class<?> getColumnClass(int column){
switch (column){
case 0: return String.class;
case 1: return String.class;
}
return null; // default case
}
@Override
public void setValueAt(Object value, int row, int column) {
switch (column) {
case 0: reList.get(row).template = value.toString(); break;
case 1: reList.get(row).comment = value.toString(); break;
}
// uncommenting the below often causes IndexOutOfBoundsException: Invalid range exception
fireTableCellUpdated(row, column);
} // end setValueAt
} // end RETableModel
} // end class TableExample
问题可以重现如下：运行上面的例子，点击“Add/Insert”按钮将新行追加到表格中，点击任一列标题重新排序表格，然后点击“Delete”按钮：抛出“IndexOutOfBoundsException”，表示TableModel的getValueAt方法指定的“行”索引有缺陷。
我认为这个问题与我的 TableModel.getValueAt（可能还有 .setValueAt ???）方法在 TableModel 列索引和 View 列索引之间转换的需要有关，但是，对于我的一生，我可以'不知道如何或在哪里进行转换。此外，这个问题 (Convert modelRowIndex to viewRowIndex for sorted JTable) 表明需要在 TableModel 和 View 行索引之间进行转换，并且表重新排序必须在索引转换完成之前发生。
尽我所能，我无法弄清楚如何进行转换和/或如何确保在表格更新和重新排序后发生转换。我需要听众吗？如果是这样，它应该是什么样子？
您能否提供一些澄清和帮助？
【问题讨论】：