Question

I’m trying to make a login screen for an application. During the login, many SQL calls will be made to a MySQL database, and it may take a few seconds to set everything up. I’d like to display a status screen via Card Layout and update a JLabel while the background thread is running.

Here’s the gist of what I have for my Worker Thread:

public class LoginPrepThread extends Thread {

    private final UIMain parent;

    public LoginPrepThread(UIMain w){
        parent = w;
    }

    public void exec(){
        EventQueue.invokeLater(this);
    }

    public void run(){
        try{
            //SqlHelper sql = SqlHelper.instance;
            sleep(500);
            parent.getLoadingLable().setText("Fetching preferences...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Scanning workbench...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Updating permissions...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Finished...Please wait");
            parent.getMainFrame().revalidate();
            sleep(1000);
            parent.getLayout().show(parent.getMainFrame().getContentPane(), "view.main");
        }catch(Exception e){

        }
    }

}

Here is how I am calling it (Inside the event of a JButton, after authenticating):

setActiveProfile(user);
layout.show(frame.getContentPane(), "view.loading");
frame.repaint();
LoginPrepThread pt = new LoginPrepThread(thisTrick);
pt.exec();

I put some dummy events in for now, but the status label doesn’t change…any suggestions?

Answer 1

A simple swing worker solved it. I guess I wasn’t good enough on my google’ing

public class LoginPrepThread extends SwingWorker<String,String> {

    private final UIMain parent;

    public LoginPrepThread(UIMain w){
        parent = w;
    }

    @Override
    protected String doInBackground() throws Exception {
        try{
            publish("Fetching preferences...");
            Thread.sleep(1000);
            publish("Updating permissions...");
            Thread.sleep(1000);
            publish("Scanning workbench...");
            Thread.sleep(1000);
            publish("Finalizing...");
            Thread.sleep(2000);
            publish("Finished...Please wait");
            Thread.sleep(1000);
            parent.getLayout().show(parent.getMainFrame().getContentPane(), "view.main");
        }catch(Exception e){

        }
        return null;
    }

    protected void process(List<String> item) {
        parent.getLoadingLable().setText(item.get(0));
    }

}