Question

The concept of my code is that, it will initially retrieve distinct names from a column ‘tname’ of my access database table ‘try’. It will add those items in a combobox. Once we select an item in the combo box, the data of the row containing tname as the selected item is retrieved and showed in textfields. Then I will make some changes to the text field content. After that, if I click ‘Save’ button, then all the data of the row containing tname as the selected combobox item must be updated with the new content in the textfields.

Everything goes fine, except the last one. When I click ‘save’ it considers only the previous text(the one intially retrieved from the database when we select combobox) and not the changes made to it. Kindly help me to diagnose the problem.

Thanks in advance.

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
import java.util.Date;
import java.sql.*;
import java.text.*;

public class gut implements ActionListener
{
JComboBox ctn;
JTextField cm,exd,stk,cst,sup,snum,r;
String stn,scm,sexd,sst,scst,ssup,ssnum,sr,icm,iexd,istk,icst,isup,isnum,ir;
JLabel lt,lc,le,ls,lcs,lsp,lspn,lr;
JButton s;
JFrame gp=new JFrame();

public gut()
{
gp.setSize(500,500);
gp.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

gp.setLayout(null);

lt=new JLabel("Tablet Name",JLabel.RIGHT);
lc=new JLabel("Composition",JLabel.RIGHT);
le=new JLabel("Expiry Date (dd/mm/yyyy)",JLabel.RIGHT);
ls=new JLabel("Stock",JLabel.RIGHT);
lcs=new JLabel("Cost",JLabel.RIGHT);
lsp=new JLabel("Supplier",JLabel.RIGHT);
lspn=new JLabel("Supplier Number",JLabel.RIGHT);
lr=new JLabel("Rack",JLabel.RIGHT);

lt.setBounds(100,120,120,20);
lc.setBounds(100,140,120,20);
le.setBounds(60,160,160,20);
ls.setBounds(100,180,120,20);
lcs.setBounds(100,200,120,20);
lsp.setBounds(100,220,120,20);
lspn.setBounds(100,240,120,20);
lr.setBounds(100,260,120,20);

ctn=new JComboBox();
cm=new JTextField();
exd=new JTextField();
stk=new JTextField();
cst=new JTextField();
sup=new JTextField();
snum=new JTextField();
r=new JTextField();


ctn.setBounds(240,120,120,20);
cm.setBounds(240,140,120,20);
exd.setBounds(240,160,120,20);
stk.setBounds(240,180,120,20);
cst.setBounds(240,200,120,20);
sup.setBounds(240,220,120,20);
snum.setBounds(240,240,120,20);
r.setBounds(240,260,120,20);

try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn=DriverManager.getConnection("jdbc:odbc:vasantham","","");
Statement st=conn.createStatement();
ResultSet rs=st.executeQuery("select DISTINCT tname from try");

while(rs.next())
{
 ctn.addItem(rs.getString("tname"));
}

conn.close();
}
catch(Exception e)
{
}

gp.add(lt);gp.add(ctn);
gp.add(lc);gp.add(cm);
gp.add(le);gp.add(exd);
gp.add(ls);gp.add(stk);
gp.add(lcs);gp.add(cst);
gp.add(lsp);gp.add(sup);
gp.add(lspn);gp.add(snum);
gp.add(lr);gp.add(r);

ctn.addActionListener(this);
s=new JButton("Save");
s.setBounds(200,300,100,20);
gp.add(s);
s.addActionListener(this);




gp.setVisible(true);
}
public void actionPerformed(ActionEvent evt)
{
String act=evt.getActionCommand();

String scb=(String)ctn.getSelectedItem();
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn=DriverManager.getConnection("jdbc:odbc:vasantham","","");
Statement st=conn.createStatement();
ResultSet rs=st.executeQuery("select * from try where tname='"+scb+"'");
SimpleDateFormat formatter=new SimpleDateFormat("dd/MM/yyyy");

while(rs.next())
{
icm=rs.getString("composition");
iexd=formatter.format(rs.getDate("exdate"));
istk=Integer.toString(rs.getInt("stock"));
icst=rs.getString("cost");
isup=rs.getString("sup");
isnum=rs.getString("supnum");
ir=rs.getString("rack");
}

cm.setText(icm);
exd.setText(iexd);
stk.setText(istk);
cst.setText(icst);
sup.setText(isup);
snum.setText(isnum);
r.setText(ir);


conn.close();
}
catch(Exception e)
{
System.out.println(e);
}


if(act.equals("Save"))
{
scm=cm.getText();
sexd=exd.getText();
sst=stk.getText();
scst=cst.getText();
ssup=sup.getText();
ssnum=snum.getText();
sr=r.getText();
System.out.println(scm+","+sexd+","+sst+","+scst+","+ssup+","+ssnum+","+sr);
try
{

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn=DriverManager.getConnection("jdbc:odbc:vasantham","","");
PreparedStatement ps=conn.prepareStatement("UPDATE try set composition=?,exdate=?,stock=?,cost=?,sup=?,supnum=?,rack=? where 

tname=?");

ps.setString(1,scm);
ps.setString(2,sexd);
ps.setString(3,sst);
ps.setString(4,scst);
ps.setString(5,ssup);
ps.setString(6,ssnum);
ps.setString(7,sr);
ps.setString(8,scb);

ps.executeUpdate();

JOptionPane.showMessageDialog(null,"Your entry has been stored successfully!!!");

}
catch(Exception e)
{
JOptionPane.showMessageDialog(null,"Error!Try again!");
System.out.println(e);

}
}
}
public static void main(String[] args)
{
new gut();
}

}

Answer 1

On top of what everybody else has already said, if you REALLY want to use a single action listener, you are going to need to work out which action has actually occurred.

You could check the source of the ActionEvent (evt.getSource()) or, more appropriately, you could assign a action command to each component using the action listener.

Check out JComboBox.setActionCommand(…) and JButton.setActionCommand(…)

After that, it’s a simple case of checking the ActionEvent.getActionCommand() property to determine the correct action to take.