更新
当 columnClass 为 Double 时，确认为JTable 上的错误无法将给定的 Object 格式化为 Number（错误 ID：7051636）。随意投票，或者如果您有其他（更好的）解决方法，请将其作为对报告的评论发布。
我正在使用扩展 AbstractTableModel 的自定义表模型构建 JTable。我的模型需要支持空行显示和排序。所以我按照这篇文章来实现它，现在工作得很好。
JTable 中的格式化字段仍然存在问题。假设我有以下模型：
public class MyModel extends AbstractTableModel{
public Object[] types= {new Integer(0), ""};
public static final Object EMPTY_ROW = "";
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
return this.EMPTY_ROW;
}
public Class<? extends Object> getColumnClass(int c) {
if (c > this.types.length - 1)
return null;
else
return this.types[c].getClass();
}
}
一切正常。但是如果我有一个 Double 而不是一个整数：
public class MyModel extends AbstractTableModel{
public Object[] types= {new Double(0.0), ""};
.......
我会得到一个非法参数异常：
编辑：@Aaron Digulla 建议后的新堆栈跟踪输出
线程“AWT-EventQueue-0”java.lang.IllegalArgumentException 中的异常：无法在 java.text.DecimalFormat.format(DecimalFormat.java:487) 处将给定对象格式化为 java.text.Format.format(Format.java) :140) 在 javax.swing.JTable$DoubleRenderer.setValue(JTable.java:5352) 在 javax.swing.table.DefaultTableCellRenderer.getTableCellRendererComponent(DefaultTableCellRenderer.java:237) 在 javax.swing.JTable.prepareRenderer(JTable.java: 5720) 在 javax.swing.plaf.basic.BasicTableUI.paintCell(BasicTableUI.java:2072) 在 javax.swing.plaf.basic.BasicTableUI.paintCells(BasicTableUI.java:1974) 在 javax.swing.plaf.basic.BasicTableUI .paint(BasicTableUI.java:1770) 在 javax.swing.plaf.ComponentUI.update(ComponentUI.java:143) 在 javax.swing.JComponent.paintComponent(JComponent.java:752) 在 javax.swing.JComponent.paint(JComponent.java:1029) 在 javax.swing.JComponent.paintChildren(JComponent.java:862) 在 javax.swing.JComponent.paint(JComponent.java:1038) 在 javax. swing.JViewport.paint(JViewport.java:747) at javax.swing.JComponent.paintChildren(JComponent.java:862) at javax.swing.JComponent.paint(JComponent.java:1038) at javax.swing.JComponent.paintChildren (JComponent.java:862) 在 javax.swing.JComponent.paint(JComponent.java:1038) 在 javax.swing.JComponent.paintChildren(JComponent.java:862) 在 javax.swing.JComponent.paint(JComponent.java: 1038) 在 javax.swing.JLayeredPane.paint(JLayeredPane.java:567) 在 javax.swing.JComponent.paintChildren(JComponent.java:862) 在 javax.swing.JComponent.paintToOffscreen(JComponent.java:5131) 在 javax。摇摆。BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:278) at javax.swing.RepaintManager.paint(RepaintManager.java:1224) at javax.swing.JComponent.paint(JComponent.java:1015) at java.awt.GraphicsCallback$PaintCallback.run (GraphicsCallback.java:21) 在 sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:60) 在 sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:97) 在 java.awt.Container.paint(Container.java: 1780) 在 java.awt.Window.paint(Window.java:3375) 在 javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:796) 在 javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713) 在 javax。 swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693) 在 javax.swing.SystemEventQueueUtilities$ComponentWorkRequest。在 java.awt.EventQueue.dispatchEvent(EventQueue.java:597) 在 java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread) 在 java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209) 运行(SystemEventQueueUtilities.java:125) .java:269) 在 java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) 在 java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) 在 java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)在 java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) 在 java.awt.EventDispatchThread.run(EventDispatchThread.java:122)597) 在 java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) 在 java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) 在 java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) 在 java. awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) 在 java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) 在 java.awt.EventDispatchThread.run(EventDispatchThread.java:122)597) 在 java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) 在 java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) 在 java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) 在 java. awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) 在 java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) 在 java.awt.EventDispatchThread.run(EventDispatchThread.java:122)java.awt.EventDispatchThread.run(EventDispatchThread.java:122) 处的 EventDispatchThread.pumpEvents(EventDispatchThread.java:161)java.awt.EventDispatchThread.run(EventDispatchThread.java:122) 处的 EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
为什么这个？
getValueAt 总是返回相同的值来填充所有表条目。这仅用于调试：
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
return this.EMPTY_ROW;
}
例如，如果我更改为：
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
return new Integer(3);
//or return new Double(3.3);
//return new String("foobar"); doesn't work
}
即使表的某些字段是字符串，也一切正常。它向我建议，因为 Integer 和 Double 可以转换为 String，这不会造成问题。无论如何，我想了解为什么像我的 EMPTY_ROW 这样的通用对象可以被接受为声明的 Integer 字段的值，而这不适用于 Double 字段。
编辑2：
如果我在我的表模型中删除 getClass 方法。有用。无论如何，我想解决这个问题而不必删除该方法，即使这会迫使我实现一些自定义渲染方法。
编辑3：
这是一个SSCCE。向表中添加新值时会出现一些错误，但与渲染问题无关。
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Comparator;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SortOrder;
import javax.swing.RowSorter.SortKey;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableRowSorter;
public class TableExample extends JFrame{
public static final Object EMPTY_ROW = "";
public class EmptyRowComparator<COLUMN_TYPE extends Comparable<COLUMN_TYPE>> implements Comparator<Object>{//extends RuleBasedCollator{
private TableRowSorter<? extends AbstractTableMod> sorter;
private int column;
public EmptyRowComparator(TableRowSorter<? extends AbstractTableMod> sorter, int col) throws ParseException {
// super(arg0);
this.sorter = sorter;
this.column = col;
// TODO Auto-generated constructor stub
}
private int getSortOrder() {
SortOrder order = SortOrder.ASCENDING;
// List<? extends SortKey> keys = sorter.getSortKeys();
// sorter.getSortKeys();
//
for (SortKey sortKey : sorter.getSortKeys()) {
if (sortKey.getColumn() == this.column) {
order = sortKey.getSortOrder();
break;
}
}
return order == SortOrder.ASCENDING ? 1 : -1;
}
@Override
public int hashCode() {
// TODO Auto-generated method stub
return 0;
}
@Override
public int compare(Object arg0, Object arg1) {
// TODO Auto-generated method stub
//System.out.println("Comparing Integer arg0 " + arg0 + " arg1 " + arg1);
boolean empty1 = arg0 == EMPTY_ROW;
boolean empty2 = arg1 == EMPTY_ROW;
if (empty1 && empty2) {
return 0;
}
else if (empty1) {
return 1 * getSortOrder();
}
else if (empty2) {
return -1 * getSortOrder();
}
return ((Comparable<COLUMN_TYPE>) (COLUMN_TYPE)arg0).compareTo((COLUMN_TYPE)arg1);
// return 0;
}
}
public class ConcreteTable extends AbstractTableMod{
//
private static final long serialVersionUID = 4672561280810649603L;
private String[] columnNames = {"ID",
"description"};
Class[] types = {Integer.class, String.class};
//Object[] types = {Double.class, String.class};
private int minimumDisplayedRow;
public ConcreteTable(){
//System.out.println("DEBUG ARRAY length " + data.length);
this.minimumDisplayedRow = 10;
this.datas = new ArrayList<ArrayList<Object>>();
for (int i = 0 ; i < this.minimumDisplayedRow ; i++){
this.addEmptyRow();
}
for (int i = 0 ; i < 5 ; i++){
ArrayList<Object> row = new ArrayList<Object>();
row.add(new Integer(i));
row.add(new String("prova " + i));
this.addRow(row);
}
}
public String getColumnName(int col) {
System.out.println("getColumnName " + col + " = " + columnNames[col]);
return columnNames[col];
}
@Override
protected Class[] getTypeArray() {
// TODO Auto-generated method stub
return this.types;
}
@Override
protected ArrayList<Integer> getKeysColumnIndex() {
// TODO Auto-generated method stub
ArrayList<Integer> keys = new ArrayList<Integer>();
keys.add(0);
return keys;
}
public boolean isCellEditable(int row, int col) {
System.out.println("isCellEditable row " + row + " col " + col);
if (col == 1){
System.out.println("TRUE");
return true;
}
return false;
}
/*note: generated keys must be in the same order they appear in the table*/
@Override
protected Object getGeneratedKeys(int col) {
// TODO Auto-generated method stub
if (col != 0 )
return null;
return new Integer(this.rowNumber);
}
@Override
protected int getMinimumDisplayedRow() {
// TODO Auto-generated method stub
return this.minimumDisplayedRow;
}
}
public abstract class AbstractTableMod extends AbstractTableModel {
ArrayList<ArrayList<Object>> datas ;
protected int rowNumber = 0;
protected abstract Class[] getTypeArray();
protected abstract ArrayList<Integer> getKeysColumnIndex();
protected abstract Object getGeneratedKeys(int col);
protected abstract int getMinimumDisplayedRow();
public int getRowCount(){
return this.datas.size() ;
}
@Override
public int getColumnCount() {
return this.getTypeArray().length;
}
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
if (rowIndex >= this.rowNumber ){
return EMPTY_ROW;
}
try{
ArrayList<Object> row = this.datas.get(rowIndex);
if (row == null)
return null;
Object obj = row.get(columnIndex);
return obj;
}catch(IndexOutOfBoundsException e){
return null;
}
}
public void setValueAt(Object value, int row, int col) {
//System.out.println("setValueAt object : " + value.getClass().getName());
Class<? extends Object> targetColClass = this.getColumnClass(col);
if (!targetColClass.isInstance(value))
return;
if (value instanceof String){
String stringVal = (String)value;
if (stringVal.compareTo("") == 0)
return;
}
if (row >= this.rowNumber){
ArrayList<Object> newRow = new ArrayList<Object>();
ArrayList<Integer> keysIndexList = this.getKeysColumnIndex();
for (int i = 0 ; i < this.getColumnCount(); i++){
if (i == col){
newRow.add(value);
}else if (keysIndexList.contains(i)){
newRow.add(this.getGeneratedKeys(i));
}else{
newRow.add(EMPTY_ROW);
}
}
this.addRow(newRow);
}else{
this.datas.get(row).set(col, value);
}
this.fireTableCellUpdated(row, col);
}
public Class<? extends Object> getColumnClass(int c) {
System.out.println("AbstractTable: getColumnClass");
if (c > this.getTypeArray().length - 1)
return null;
else
return this.getTypeArray()[c];
}
public void addEmptyRow(){
ArrayList<Object> emptyRow = new ArrayList<Object>();
for (int i = 0 ; i < this.getTypeArray().length; i++){
emptyRow.add(EMPTY_ROW);
}
this.datas.add(emptyRow);
}
public void addRow(ArrayList<Object> row){
Object[] types = this.getTypeArray();
if (types.length != row.size())
return;
for (int i = 0 ; i < row.size() ; i++){
Class<? extends Object> targetColClass = this.getColumnClass(i);
Object rowItem = row.get(i);
}
this.datas.add(this.rowNumber, row);
this.rowNumber++;
if (this.rowNumber < this.getMinimumDisplayedRow())
this.datas.remove(this.datas.size() -1 );
this.fireTableRowsInserted(this.rowNumber , this.rowNumber );
}
}
public TableExample(){
super("JTable example");
getContentPane().setLayout(new BoxLayout(getContentPane(), BoxLayout.Y_AXIS));
ConcreteTable model = new ConcreteTable();
JTable tab = new JTable(model);
TableRowSorter<ConcreteTable> sorter = new TableRowSorter<ConcreteTable>(model);
try {
sorter.setComparator(0, new EmptyRowComparator<Integer>(sorter,0));
sorter.setComparator(1, new EmptyRowComparator<String>(sorter,1));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
tab.setRowSorter(sorter);
JScrollPane table = new JScrollPane(tab);
this.getContentPane().add(table);
this.setSize(600, 400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
new TableExample();
}
}
如果你尝试改变
Class[] types = {Integer.class, String.class};
和 ：
Class[] types = {Double.class, String.class};
你可以看到问题。