我想将自定义JComboBox实现为JTable的CellEditor。我采用了原始Java示例并通过实现体育课程
对其进行了修改请运行源代码，单击JComboBox，您将注意到ComboBox打开时不再选择所选项目。 我想将renderered项目保留在组合框选择中。
原文：http://docs.oracle.com/javase/tutorial/uiswing/components/table.html#combobox
public class Sport {
private Integer id;
private String name;
public Sport(String name){
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String toString() {
return this.name;
}
}
public class TableRenderDemo extends JPanel {
private boolean DEBUG = false;
public TableRenderDemo() {
super(new GridLayout(1,0));
JTable table = new JTable(new MyTableModel());
table.setPreferredScrollableViewportSize(new Dimension(500, 70));
table.setFillsViewportHeight(true);
//Create the scroll pane and add the table to it.
JScrollPane scrollPane = new JScrollPane(table);
//Set up column sizes.
initColumnSizes(table);
//Fiddle with the Sport column's cell editors/renderers.
setUpSportColumn(table, table.getColumnModel().getColumn(2));
//Add the scroll pane to this panel.
add(scrollPane);
}
/*
* This method picks good column sizes.
* If all column heads are wider than the column's cells'
* contents, then you can just use column.sizeWidthToFit().
*/
private void initColumnSizes(JTable table) {
MyTableModel model = (MyTableModel)table.getModel();
TableColumn column = null;
Component comp = null;
int headerWidth = 0;
int cellWidth = 0;
Object[] longValues = model.longValues;
TableCellRenderer headerRenderer =
table.getTableHeader().getDefaultRenderer();
for (int i = 0; i < 5; i++) {
column = table.getColumnModel().getColumn(i);
comp = headerRenderer.getTableCellRendererComponent(
null, column.getHeaderValue(),
false, false, 0, 0);
headerWidth = comp.getPreferredSize().width;
comp = table.getDefaultRenderer(model.getColumnClass(i)).
getTableCellRendererComponent(
table, longValues[i],
false, false, 0, i);
cellWidth = comp.getPreferredSize().width;
if (DEBUG) {
System.out.println("Initializing width of column "
+ i + ". "
+ "headerWidth = " + headerWidth
+ "; cellWidth = " + cellWidth);
}
column.setPreferredWidth(Math.max(headerWidth, cellWidth));
}
}
public void setUpSportColumn(JTable table,
TableColumn sportColumn) {
//Set up the editor for the sport cells.
JComboBox comboBox = new JComboBox();
comboBox.addItem("Snowboarding");
comboBox.addItem("Rowing");
comboBox.addItem("Knitting");
comboBox.addItem("Speed reading");
comboBox.addItem("Pool");
comboBox.addItem("None of the above");
sportColumn.setCellEditor(new DefaultCellEditor(comboBox));
//Set up tool tips for the sport cells.
DefaultTableCellRenderer renderer =
new DefaultTableCellRenderer();
renderer.setToolTipText("Click for combo box");
sportColumn.setCellRenderer(renderer);
}
class MyTableModel extends AbstractTableModel {
private String[] columnNames = {"First Name",
"Last Name",
"Sport",
"# of Years",
"Vegetarian"};
private Object[][] data = {
{"Kathy", "Smith",new Sport("Snowboarding"),
new Integer(5), new Boolean(false)},
{"John", "Doe",
new Sport("Rowing"), new Integer(3), new Boolean(true)},
{"Sue", "Black",
new Sport("Knitting"), new Integer(2), new Boolean(false)},
{"Jane", "White",
new Sport("Speed reading"), new Integer(20), new Boolean(true)},
{"Joe", "Brown",
new Sport("Pool"), new Integer(10), new Boolean(false)}
};
public final Object[] longValues = {"Jane", "Kathy",
"None of the above",
new Integer(20), Boolean.TRUE};
public int getColumnCount() {
return columnNames.length;
}
public int getRowCount() {
return data.length;
}
public String getColumnName(int col) {
return columnNames[col];
}
public Object getValueAt(int row, int col) {
return data[row][col];
}
/*
* 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 getColumnClass(int c) {
return getValueAt(0, c).getClass();
}
/*
* 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[row][col] = value;
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[i][j]);
}
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("TableRenderDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
TableRenderDemo newContentPane = new TableRenderDemo();
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();
}
});
}
}
好的我包括以下内容，但仍然存在同样的问题：
public void setUpSportColumn(JTable table,
TableColumn sportColumn) {
//Set up the editor for the sport cells.
JComboBox<Sport> comboBox = new JComboBox();
comboBox.addItem(new Sport("Snowboarding"));
comboBox.addItem(new Sport("Rowing"));
comboBox.addItem(new Sport("Knitting"));
comboBox.addItem(new Sport("Speed reading"));
comboBox.addItem(new Sport("Pool"));
comboBox.addItem(new Sport("None of the above"));
sportColumn.setCellEditor(new DefaultCellEditor(comboBox));
//Set up tool tips for the sport cells.
DefaultTableCellRenderer renderer =
new DefaultTableCellRenderer();
renderer.setToolTipText("Click for combo box");
sportColumn.setCellRenderer(renderer);
// sportColumn.setCellEditor(new MyCellEditor());
}
答案 0 :(得分：2)
您的模型包含Sport类的实例，但JCombobox包含字符串。这就是设置选择无法找到适当值的原因。
尝试添加这样的运动
comboBox.addItem(new Sport("Rowing"));
并且重写Sport类的toString（）方法以返回名称（更简单的方法）。或者将自定义渲染器添加到运动组合框中。
答案 1 :(得分：2)
您还需要覆盖Sport类的equals(...)和hashcode(...)方法。 Java Collection方法依赖于这些方法来确定对象实例在进行搜索时的相等性。
@Override
public boolean equals(Object object)
{
Sport sport = (Sport)object;
return this.name.equals( sport.getName() );
}
@Override
public int hashCode()
{
return name.hashCode();
}
另外，请阅读Object API以获取有关这些方法的更多信息。