我试图在单击combox时获取当前行数据。 我的问题是，如果我尝试获取有关单击组合框的详细信息，则检索到的数据是错误的。
这正在填充集合中的无效数据。请按照下面提到的确切步骤进行复制。
请运行代码以复制问题，因为该问题仅在初始选择期间有效，而在之后才有效。
注意：请仅在第二列上单击脏话
Step 1: Click on Second Column of Row 1
Step 2: Select- Item 1
Step 3: Click on Second Column of Row 2
Step 4: Select- Item 2
Step 5: Click on Second Column of Row 3
Step 6: Select- Item 3
WORKS Fine till here :)
Step 7 : Click on Second column of Row 1 and do not change an selection leave it as it is (Just click on the combobox twice)
Step 8 : Click on Second column of Row 2, DO NO CHANGES
Step 9 : Click on Second column of Row 3, DO NO CHANGES
Step 10: NOW randomly click on any of the second columns of rows(1,2,3) and see the output datamap. It really wierd why the event is
下面是示例代码：
import java.awt.Cursor;
import java.awt.FlowLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Vector;
import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.ListSelectionModel;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
public class TestJCombo extends JFrame {
public TestJCombo() {
initialize();
}
JTable jTable;
JComboBox comboBox;
Map<Integer, String> dataMap;
private void initialize() {
setSize(300, 300);
setLayout(new FlowLayout(FlowLayout.LEFT));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JTextField field = new JTextField();
field.setSize(50000, 25);
field.setText(" ");
jTable = new JTable();
comboBox = new JComboBox();
comboBox.setEditable(true);
comboBox.addItem("item 1");
comboBox.addItem("item 2");
comboBox.addItem("item 3");
comboBox.setEditable(false);
dataMap = new LinkedHashMap();
comboBox.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent e) {
if (e.getStateChange() == ItemEvent.SELECTED) {
Object selected = comboBox.getSelectedItem();
int selectedRow = jTable.getSelectedRow();
selectedRow = jTable.convertRowIndexToModel(selectedRow);
if (selectedRow != -1) {
String user = (String) jTable.getValueAt(selectedRow, 0);
String data = "Row: " + (selectedRow + 1) + " :::: " + user + " , "
+ comboBox.getSelectedItem();
dataMap.put(selectedRow + 1, "[" + user + " - " + comboBox.getSelectedItem() + "]");
if (selected != null) {
field.setText(data);
}
System.out.println("Current data map:: " + dataMap);
}
}
}
});
jTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
jTable.setRowHeight(30);
jTable.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
DefaultTableModel myTableMdl = new DefaultTableModel();
myTableMdl.addColumn("User");
myTableMdl.addColumn("Role");
jTable.setModel(myTableMdl);
jTable.getColumn("Role").setCellEditor(new DefaultCellEditor(comboBox));
Vector tableData;
for (int i = 1; i <= 7; i++) {
tableData = new Vector();
tableData.add("User " + i);
myTableMdl.addRow(tableData);
}
getContentPane().add(jTable);
getContentPane().add(field);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TestJCombo().setVisible(true);
}
});
}
}
答案 0 :(得分：0)
问题是您在错误的组件上使用了错误的侦听器。您不应将侦听器添加到组合框。使用编辑器的目的是编辑数据并更新TableModel。您不应引用组合框进行进一步处理。
因此，您应该将TableModelListener添加到TableModel。然后，只要更改第2列中的值，就会生成TableModelEvent。 TableModelEvent将包含已更改的单元格的行/列信息。
您可以签出：JTable -> TableModeListener，了解使用TableModelListener的基本示例。您需要检查第二列是否发生更改，然后更新地图。
还请注意，您错误地使用了convertRowIndexToModel（）方法：
selectedRow = jTable.convertRowIndexToModel(selectedRow);
...
String user = (String) jTable.getValueAt(selectedRow, 0);
首先，如果对表视图进行排序或过滤，则只需要担心覆盖行索引。在提供的代码中，您也不执行任何操作，因此无需转换索引。
但是，如果您曾经对视图进行过某种过滤，则需要将视图行转换为模型行，然后必须从模型而不是视图访问数据。因此代码将是：
String user = (String) jTable.getModel().getValueAt(selectedRow, 0);
答案 1 :(得分：-1)
问题是您要创建一个JComboBox，然后将其放在列中的所有单元格上。您引用的是JComboBox，而不是为每个单元格创建一个新的单元格。这就是为什么当您按照提到的 10个步骤进行操作时，获得的结果是愚蠢和毫无意义的。
这是解决方法，为列1（角色列）中的所有单元格创建自定义TableCellEditor。目标是为每个单元格创建一个全新的JComboBox。这是通过将JTable的声明更改为jtable = new JTable(){...};来覆盖getCellEditor(...){...}方法来实现的。此外，方法private JComboBox createComboBox() {...}是创建全新JComboBox所需要的。
现在，我们将取出addItemListener并将其替换为addActionListener。这是必需的，因为如果用户选择已选择的项目，则itemStateChanged中的ItemListener将不会被调用。我们需要稍微重复一下两次鼠标，一次单击显示下拉列表，第二次选择项目（如果不需要，可以跳过此步骤）。
我还编辑了您的代码，以使其更具可读性和效率。
这是MVCE：
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.table.TableCellEditor;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Vector;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.ListSelectionModel;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
public class TestJCombo extends JFrame {
JTable jTable;
//JComboBox comboBox;//not needed, replaced by the createComboBox() method.
Map<Integer, String> dataMap;
final JTextField FIELD = new JTextField(25);//must put this globally.
//Since it is final, it should be all in upper case
//It is a good practice to put the global variables on top and constructor(s) below.
public TestJCombo() {
initialize();
}
private void initialize() {
//use pack(); instead setSize(...); I used it at the end of this method.
//setSize(300, 300);
setLayout(new FlowLayout(FlowLayout.LEFT));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
//both lines not needed, it has been taken care of when FIELD was declared.
//FIELD.setSize(50000, 25);
//FIELD.setText(" "
// + " ");
//Must create a seperate TableCellEditor for each cell in the table.
jTable = new JTable() {
public TableCellEditor getCellEditor(int row, int column) {
int modelColumn = convertColumnIndexToModel(column);
//if the cell lies in the second column, create a custom cell editor.
if (modelColumn == 1) {
return (TableCellEditor) new DefaultCellEditor(createComboBox());
} else {
return super.getCellEditor(row, column);
}
}
};
//comboBox = new JComboBox();
//comboBox.setEditable(true);
//comboBox.addItem("item 1");
//comboBox.addItem("item 2");
//comboBox.addItem("item 3");
//comboBox.setEditable(false);
dataMap = new LinkedHashMap();
jTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
jTable.setRowHeight(30);
jTable.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
DefaultTableModel myTableMdl = new DefaultTableModel();
myTableMdl.addColumn("User");
myTableMdl.addColumn("Role");
jTable.setModel(myTableMdl);
//we have our own custom CellEditor, this is not needed
//jTable.getColumn("Role").setCellEditor(new DefaultCellEditor(comboBox));
Vector tableData;
for (int i = 1; i <= 7; i++) {
tableData = new Vector();
tableData.add("User " + i);
myTableMdl.addRow(tableData);
}
//It is better practice to add everything to a
//panel and then add that panel to the frame.
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.add(jTable);
panel.add(Box.createRigidArea(new Dimension(0, 10)));//add some space
panel.add(FIELD);
getContentPane().add(panel, BorderLayout.CENTER);
pack();//should use this.
}
private JComboBox createComboBox() {
JComboBox comboBox = new JComboBox();
comboBox.setEditable(true);
comboBox.addItem("item 1");
comboBox.addItem("item 2");
comboBox.addItem("item 3");
comboBox.setEditable(false);
//Add an ActionListener so that it would also detect if the user selects
//the same item. The itemStateChanged in the ItemListener will not be
//invoked if the user selects the item that is already selected.
comboBox.addActionListener(new ActionListener() {
//To update the result everytime the user selects an item
//(regardless if it was selected or not), we need to "mock"
//a two-click operation. The first click will show the
//drop-down list to select from and the second will
//allow the user to select the desired choice to be selected.
boolean doubleClick = false;
@Override
public void actionPerformed(ActionEvent ae) {
if (doubleClick) {
int selectedRow = jTable.getSelectedRow();
selectedRow = jTable.convertRowIndexToModel(selectedRow);
Object selected = comboBox.getSelectedItem();
if (selectedRow != -1 && selected != null) {
String user = (String) jTable.getValueAt(selectedRow, 0);
String data = "Row: " + (selectedRow + 1) + " :::: " + user + " , "
+ comboBox.getSelectedItem();
dataMap.put(selectedRow + 1, "[" + user + " - "
+ comboBox.getSelectedItem() + "]");
FIELD.setText(data);
System.out.println("Current data map:: " + dataMap);
}
doubleClick = false;
}
doubleClick = true;
}
});
// comboBox.addItemListener(new ItemListener() {
//
// public void itemStateChanged(ItemEvent e) {
// if (e.getStateChange() == ItemEvent.SELECTED) {
//
// Object selected = comboBox.getSelectedItem();
//
// int selectedRow = jTable.getSelectedRow();
// selectedRow = jTable.convertRowIndexToModel(selectedRow);
// if (selectedRow != -1) {
// String user = (String) jTable.getValueAt(selectedRow, 0);
// String data = "Row: " + (selectedRow + 1) + " :::: " + user + " , "
// + comboBox.getSelectedItem();
// dataMap.put(selectedRow + 1, "[" + user + " - "
// + comboBox.getSelectedItem() + "]");
// if (selected != null) {
// FIELD.setText(data);
// }
// System.out.println("Current data map:: " + dataMap);
// }
// }
//
// }
// });
return comboBox;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TestJCombo().setVisible(true);
}
});
}
}