TableModelListener（第87行/ HERE-1）是否干扰了我的JTable的addRow方法（第139行，HERE-2）？如果是这样，我该如何解决？
这段代码会编译但是当我使用＆＃34;添加行＆＃34;时会抛出错误。按钮。 错误是： （堆栈跟踪的时间要长得多，但我已经将它缩减为关于我的类而不是java API的行）
线程中的异常＆＃34; AWT-EventQueue-0＆＃34; java.lang.ArrayIndexOutOfBoundsException：
在HPLC.addRow（HPLC.java:142）
at HPLC.lambda $ new $ 1（HPLC.java:109）
这只是一个问题，因为我已经添加了TableModelListener。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
class HPLC extends JFrame
{
public static void main (String [] args)
{
new HPLC();
}
HPLC()
{
//create window
JFrame frame = new JFrame();
frame.setTitle("HPLC Calculator");
frame.setSize(500,750);
frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new GridBagLayout());
//row 0
JLabel title = new JLabel("HPLC Gradient Calculator");
gridBagAdd(panel, title, 0,0,4,1, GridBagConstraints.CENTER);
//row 1
JLabel flowLabel = new JLabel("Flow rate");
gridBagAdd(panel, flowLabel, 0,1,1,1, GridBagConstraints.CENTER);
JTextField flow = new JTextField(5);
gridBagAdd(panel, flow, 1,1,1,1, GridBagConstraints.CENTER);
JLabel mlMinLabel = new JLabel("ml/min");
gridBagAdd(panel, mlMinLabel, 2,1,1,1, GridBagConstraints.CENTER);
//row 2
JLabel numInjLabel = new JLabel("Number of injections");
gridBagAdd(panel, numInjLabel, 0,2,1,1, GridBagConstraints.CENTER);
JTextField numInj = new JTextField(5);
gridBagAdd(panel, numInj, 1,2,1,1, GridBagConstraints.CENTER);
//row 3
JLabel volALabel = new JLabel("Volume of A");
gridBagAdd(panel, volALabel, 0,3,1,1, GridBagConstraints.CENTER);
JTextField volA = new JTextField(5);
volA.setEditable(false);
gridBagAdd(panel, volA, 1,3,1,1, GridBagConstraints.CENTER);
JLabel volBLabel = new JLabel("Volume of B");
gridBagAdd(panel, volBLabel, 2,3,1,1, GridBagConstraints.CENTER);
JTextField volB = new JTextField(5);
volB.setEditable(false);
gridBagAdd(panel, volB, 3,3,1,1, GridBagConstraints.CENTER);
//row 4
JButton calculate = new JButton("calculate");
gridBagAdd(panel, calculate, 0,4,1,1, GridBagConstraints.CENTER);
JButton addRow = new JButton("add row");
gridBagAdd(panel, addRow, 1,4,1,1, GridBagConstraints.CENTER);
JButton removeRow = new JButton("remove row");
gridBagAdd(panel, removeRow, 2,4,1,1, GridBagConstraints.CENTER);
//the gradient table
String[] columns = {"Time", "%A", "%B"};
DefaultTableModel model = new DefaultTableModel(columns, 2)
{
public boolean isCellEditable(int row, int column)
//this overrides the default method to suit these conditions to make the 3rd column read only
{
if (column == 2)
return false;
return true;
}
};
JTable table = new JTable(model);
table.setFillsViewportHeight(true);
JScrollPane tablePane = new JScrollPane(table);
gridBagAdd(panel, tablePane, 0,5,4,4, GridBagConstraints.CENTER);
table.getModel().addTableModelListener(new TableModelListener()
//HERE-1 {
public void tableChanged(TableModelEvent e)
//overriding the TableModelListener method
{
//the basics in order to get the table cell
int row = e.getFirstRow();
int column = e.getColumn();
TableModel model = (TableModel)e.getSource();
String ColumnName = model.getColumnName(column);
Object data = model.getValueAt(row, column);
//what i do with that cell
volB.setText(data.toString());
}
});
//button methods
calculate.addActionListener(e -> calculate(model, volA));
addRow.addActionListener(e -> addRow(model));
removeRow.addActionListener(e -> removeRow(model));
//make visible
frame.add(panel);
frame.setVisible(true);
}
//method for placement of components
private void gridBagAdd(JPanel p, JComponent c, int x, int y, int width, int height, int align)
{
GridBagConstraints gc = new GridBagConstraints();
gc.gridx = x;
gc.gridy = y;
gc.gridwidth = width;
gc.gridheight = height;
gc.weightx = 100;
gc.weighty = 100;
gc.insets = new Insets(5,5,5,5);
gc.anchor = align;
gc.fill = GridBagConstraints.NONE;
p.add(c, gc);
}
//button method execution
private void calculate(DefaultTableModel model, JTextField volA)
{
int rowCount = model.getRowCount();
String msg = rowCount + " rows";
volA.setText(msg);
}
private void addRow(DefaultTableModel model)
{
int colCount = model.getColumnCount();
//HERE-2 Object [] newRow = new Object[colCount];
model.addRow(newRow);
}
private void removeRow(DefaultTableModel model)
{
int rowCount = model.getRowCount();
if (rowCount > 2)
model.removeRow(rowCount -1);
}
}
我喜欢我的表格，就是根据表格的内容创建一个数组，以便进行计算。已添加TableModelListener，以便％B列自动完成，总计100％。
我自学成才，这是我第一次看到任何代码。如果您对如何改进我的写作方法有任何建议，我很乐意听到。
答案 0 :(得分：2)
您正在添加一个新行，因此TableModelListener将在您的事件中为column属性返回ALL_COLUMNS常量，该值为-1 reference。
int column = e.getColumn(); // here
然后尝试在这里使用-1值：
Object data = model.getValueAt(row, column);
显然无效。
解决方案：在使用之前检查侦听器中的列值。也许您会想要为列值使用int literal。
答案 1 :(得分：2)
已添加TableModelListener，以便％B列自动完成以提供总计100％
该事件将告诉您为何生成它。在我看来，您只想在更改单元格中的值时执行代码。
所以代码应该是这样的：
public void tableChanged(TableModelEvent e)
{
if (e.getType() == TableModelEvent.UPDATE)
{
// add processing here
}
}
有关工作示例，请查看：JTable -> TableModeListener