I am creating an application in Java which retrieves some information from a MySQL database and then displays it in a JTable on the screen.
The code I am using to get and put the information into a DefaultListModel<> is shown below. The DefaultListModel<> is then fed to the JTable which displays the information onto the screen.
SwingWorker<Void, Void> worker = new SwingWorker< Void, Void>() {
@Override
public Void doInBackground() {
String SQL = "SELECT * FROM AddABill";
try {
Statement stmt = GlobalVars.conn.createStatement();
ResultSet rs = stmt.executeQuery(SQL);
menuOptions.clear();
while(rs.next()){
menuOptions.addElement(rs.getString(1) + " - " + rs.getString(2));
}
rs.close();
stmt.close();
}
catch (SQLException e) {
System.out.println("An Error Was Detected! :/");
}
return null;
}
@Override
public void done(){
loadingGif.setVisible(false);
}
};
worker.execute();
The issue I am having is that sometimes the information is displayed onto the screen and sometimes it isn't. Since there is no change in the query used I am assuming it is something to do with the MySQL connection.
The JTable and MenuOptions are setup like this
menuOptions = new DefaultListModel<>();
menuOptions.addElement("");
menuList = new JList<>(menuOptions);
menuList.setFont(new Font("Myriad Hebrew", Font.PLAIN, 32));
menuList.setBackground(Color.decode("#005952"));
menuList.setForeground(Color.decode("#BEC423"));
menuList.setSelectionBackground(Color.decode("#660033"));
menuList.setSelectionForeground(Color.decode("#FFFFFF"));
So the question I am wondering is how can I make sure that the information is always displayed on the screen. A picture of when it is displayed and not displayed is shown below.
Displayed:
Not Displayed:
On a final note to get the information to show I have to keep on re-running the code until it is eventually shown.
I have solved the issue by adding the information into the table from the done() function. The code is below
SwingWorker<Void, Void> worker = new SwingWorker< Void, Void>() {
String[] billItems = null;
@Override
public Void doInBackground() {
String SQL = "SELECT * FROM AddABill";
try {
Statement stmt = GlobalVars.conn.createStatement();
ResultSet rs = stmt.executeQuery(SQL);
//Set The Cursor To Last Position
rs.last();
int totalRows = rs.getRow();
billItems = new String[totalRows];
//Set The Cursor Back To The Start
rs.beforeFirst();
while(rs.next()){
int rowNum = rs.getRow() - 1;
billItems[rowNum] = rs.getString(1) + " - " + rs.getString(2);
}
rs.close();
stmt.close();
}
catch (SQLException e) {
System.out.println("An Error Was Detected! :/");
}
return null;
}
@Override
public void done(){
menuOptions.clear();
for(int i = 0; i < billItems.length; i++){
menuOptions.addElement(billItems[i]);
}
loadingGif.setVisible(false);
}
};