等到按下按钮

Question

There are a lot questions on this, but they weren't able to help me or I didn't understand it..

Basically I want user to press the button before system goes back to main method. In this case if system goes back to main method, system will quit.

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class test123 implements ActionListener{


JTable table;
JButton button;
JFrame frame; 

public test123 (){

    frame = new JFrame();
    frame.setLayout(null);

    button = new JButton("Finish");
    button.setBounds(200, 10, 70, 40);
    button.addActionListener(this);

    frame.add(button);


    frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
    frame.setSize(600, 200);
    frame.setVisible(true);
    frame.setTitle("TEst123");  
}


public void actionPerformed(ActionEvent e){
    if(e.getSource() == button){
        System.out.println("message....");
    }
}

public static void main(String arg[]){
    test123 gui = new test123();

    System.exit(0);

}
}

Sorry if it was just me lacking the understanding and thank you for help.

EDIT: Maybe I explained this incorrectly or displayed it incorrectly. Lets say if the system goes back to main system it will do something I don't want, therefor I want the user to press the button to go back to the main system or do "the thing". Sorry for bad explanation, including this one.

This class is separate from my work and I just used it to test stuff... In my project, user can choose from several buttons (lets say main method is the menu in this case). The user presses a button goes to a new window/frame, if the program doesn't pause or waits for button to be pressed, it will go back to main method.

Answer 1

The quick answer is what Andrew Thompson wrote in his comment:

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTable;

public class test123 implements ActionListener {

    JTable table;
    JButton button;
    JFrame frame;

    public test123() {

        frame = new JFrame();
        frame.setLayout(null);

        button = new JButton("Finish");
        button.setBounds(200, 10, 70, 40);
        button.addActionListener(this);

        frame.add(button);

        frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
        frame.setSize(600, 200);
        frame.setVisible(true);
        frame.setTitle("TEst123");
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == button) {
            System.out.println("message....");
//          System.exit(0);
            frame.dispose(); // better than exit
        }
    }

    public static void main(String arg[]) {
        test123 gui = new test123();
    }

}

but Java class name should start with upper case test123 -> Test123 (but you can find a lot better name for sure).

Why not to extend JFrame also?

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;

public class Test123 extends JFrame implements ActionListener {

    private static final long serialVersionUID = 3378774311250822914L;

//  private JTable table;
    private JButton button;
//  JFrame frame;

    public Test123() {

//      frame = new JFrame();
        this.setLayout(null);

        button = new JButton("Finish");
        button.setBounds(200, 10, 70, 40);
        button.addActionListener(this);

        this.add(button);

        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        this.setSize(600, 200);
        this.setTitle("Test123");
        this.setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == button) {
            System.out.println("message....");
//          System.exit(0);
            this.dispose();
        }
    }

    public static void main(String arg[]) {
        Test123 gui = new Test123();
    }

}

Read more in Concurrency in Swing tutorial to find out how to deal with long running tasks out of dispatch thread...

---

From your question it seems, that you do not know how swing application behaves. You create a GUI and the you are waiting for user's input. So basically you do not care what was your program executing, when user pressed the button... (and therefore it doesn't matter where it returns to)