CODEWITHSUNDEEP
javamultithreadingswing
Bruhman
Bruhman

Reputation: 33

How to make multithreaded swing gui application start/stop thread with 2 buttons

I have a separate class implementing runnable, but whenever I start the thread, I cannot press the stop button on the GUI. I'm not sure whether I am doing things correctly as I have never done multithreading before in Java project of this scale. I'm already far into the project, and I hadn't tested the stop thread function until now.

I looked into implementing things like this, but I wasn't sure how: https://docs.oracle.com/javase/tutorial/uiswing/concurrency/dispatch.html

These are the bits of code to start and stop the thread

Runnable r;
Thread t1;
String token,proxies,sID,msgC;

JButton btnNewButton_1 = new JButton("Start Thread");
        btnNewButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                token=txtEnterBotToken.getText();
                proxies=textArea.getText();
                sID=txtEnterServerId.getText();
                msgC=textField_1.getText();
                r=null;
                t1=new Thread(r);
                r = new BotFunc(token,proxies,sID,msgC);
                if(!t1.isAlive())t1.start();
                }
            });

JButton btnNewButton_2 = new JButton("Stop Thread");
        btnNewButton_2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                t1.interrupt();
                t1=new Thread(r);
            }
        });

This is what my class which is being initialized in the other thread looks like

public class BotFunc implements Runnable {
    private String token1,proxies1,sID1,msgC1;
    
    public BotFunc(String token,String proxies,String sID,String msgC) {
           token1=token;proxies1=proxies;sID1=sID;msgC1=msgC;
           run();
       }
    
    public void run()
    {
        {
            {
                System.out.println("t1 running");
                //there were about 1000 lines here that I deleted in which I start 2 other threads
            }
        }
    }
}

you can also see where I write "//there were about 1000 lines here that I deleted in which I start 2 other threads." The classes which are initialized are mostly similar to the BotFunc class and I was wondering how I could interrupt these threads as well.

Upvotes: 1

Views: 240

Answers (1)

markspace
markspace

Reputation: 11020

I think the problem is calling run() from the constructor of BotFunc:

public BotFunc(String token,String proxies,String sID,String msgC) {
       token1=token;proxies1=proxies;sID1=sID;msgC1=msgC;
       run();  // <---- DON'T DO THIS!!
   }

Calling run() like this will execute the code body on the main GUI thread, causing the GUI to block. Don't do this.

Just to explain a bit more, Thread.start() calls run() for you, there's no need for you to do it.

/* Fake Thread implementation */
public class Thread {
   public void start() {
     /* starts a new thread, then... */
     run(); // just calls run()
   }
}

Calling run() from the ctor causes the GUI thread to run the body of your Runnable, because it's the GUI thread that calls the ctor, and the body of the ctor is just executing on the GUI thread as a result.

Upvotes: 2

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