在运行时更新Jtable? [英] Update the Jtable at Runtime?

问题描述

当用户进行编辑并在其中输入新值时，我正在尝试更新JTable，但是出现转换错误.

I am trying to update a JTable when a users edit and enters new values into it, but I am getting casting error.

到目前为止编码:

import java.io.*;
import java.awt.*;
import java.util.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.table.*;

 public class Stackq extends AbstractTableModel {
    Vector data;
    Vector columns;

    public Stackq() {
  String line;
  data = new Vector();
 columns = new Vector();
  int count = 0;


  try {
FileInputStream fis = new FileInputStream("D:/joy/text/registration.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
StringTokenizer st1 = new StringTokenizer(br.readLine(), "\t");
while (st1.hasMoreTokens()) {
columns.addElement(st1.nextToken());
count++;
}
while ((line = br.readLine()) != null) {
StringTokenizer st2 = new StringTokenizer(line, "\t");
for (int i = 0; i < count; i++) {
    if (st2.hasMoreTokens())
    data.addElement(st2.nextToken());
    else
    data.addElement("");
 }
 }
 br.close();
 } catch (Exception e) {
 e.printStackTrace();
  }
   }



  public void setValueAt(Object value, int row, int col){
 ((Vector) data.get(row)).setElementAt(value, col);
 fireTableCellUpdated(row,col);
 }

 public boolean isCellEditable(int row, int col){
 //if (4 == col){
 return true;
 }
 //else {
// return false;
// }
 //}

 public void insertData(Object[] values){
 data.add(new Vector());
 for(int i =0; i<values.length; i++){
 ((Vector) data.get(data.size()-1)).add(values[i]);
       }
 fireTableDataChanged();
 }

 public void removeRow(int row){
 data.removeElementAt(row);
 fireTableDataChanged();
 }


    public int getRowCount() {
            return data.size() / getColumnCount();
    }

    public int getColumnCount() {
            return columns.size();
    }

    public Object getValueAt(int rowIndex, int columnIndex) {
            return (String) data.elementAt((rowIndex * getColumnCount())
                            + columnIndex);
    }

      public String getColumnName(int i){
      return (String)columns.get(i);
         }


    public static void main(String s[]) {
           Stackq model = new Stackq();
            JTable table = new JTable();
            table.setModel(model);



           JScrollPane scrollpane = new JScrollPane(table);
            JPanel panel = new JPanel();
            panel.add(scrollpane);
            JFrame frame = new JFrame();
            frame.add(panel, "Center");
            frame.pack();
            frame.setVisible(true);


     }
   }

错误消息:

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Vector
        at Stackq.setValueAt(Stackq.java:45)
        at javax.swing.JTable.setValueAt(JTable.java:2709)
        at javax.swing.JTable.editingStopped(JTable.java:4711)
        at javax.swing.AbstractCellEditor.fireEditingStopped(AbstractCellEditor.java:125)
        at javax.swing.DefaultCellEditor$EditorDelegate.stopCellEditing(DefaultCellEditor.java:350)
        at javax.swing.DefaultCellEditor.stopCellEditing(DefaultCellEditor.java:215)
        at javax.swing.JTable$GenericEditor.stopCellEditing(JTable.java:5465)
        at javax.swing.plaf.basic.BasicTableUI$Handler.mousePressed(BasicTableUI.java:980)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:263)
        at java.awt.Component.processMouseEvent(Component.java:6260)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)

推荐答案

您的data实例是Vector.在这行上，

Your data instance is a Vector. On this line,

((Vector) data.get(row)).setElementAt(value, col);

您可以使用data.get(row)从向量中获取单个元素，在您的情况下为String.现在，您正在尝试将String转换为带有(Vector)的Vector，这显然是行不通的.

you fetch a single element from the vector with data.get(row), which in your case is a String. Now you are trying to convert that String into a Vector with (Vector) which obviously doesn't work.

是否要确保向量中的向量安全以生成表格?也许定义通用向量的类型将有助于您发现问题，例如Vector<Vector<String>> data.

Do you want to safe a vector in a vector to produce a table? Maybe defining the type of the generic vector will help you find your problem, e.g. Vector<Vector<String>> data.

这篇关于在运行时更新Jtable?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！