How do I invoke a method to an ActionListener

**susan28** · April 27th, 2019, 05:41 PM

Hi, I'm new to Java and I am trying to write the code required for function roll to be called when rollButton is pressed and I have no idea how to do this. So I would appreciate if someone could help me. Thanks

i

mport javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.util.Random;
 
 
[CODE][CODE][CODE][CODE]public class Dice extends JFrame implements ActionListener {
    private JButton rollButton;
    private JLabel leftDice,rightDice;
    private Random randomGen;
    public Dice()   {
        super("Dice machine");
        rollButton= new JButton("Roll!");
        leftDice=new JLabel("",JLabel.CENTER);
        rightDice=new JLabel("",JLabel.CENTER);
        Container pane=this.getContentPane();
        pane.add(leftDice,BorderLayout.NORTH);
        pane.add(rightDice,BorderLayout.CENTER);
        pane.add(rollButton,BorderLayout.SOUTH);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(300,100);
        setVisible(true);
        randomGen=new Random(); // init number generator
        roll();
}
    private void roll() {
        // generate random numbers between 1 and 6
        int left=randomGen.nextInt(5)+1;
        int right=randomGen.nextInt(5)+1;
        leftDice.setText(""+left);
        rightDice.setText(""+right);
}
 
    public void actionPerformed(ActionEvent e){
     //not sure what to write here exactly
 
 
    }
    public static void main (String[] args) {
        new Dice();

[/CODE][/CODE][/CODE][/CODE]

**jim829** · April 27th, 2019, 09:09 PM

You don't invoke an actionListener directly. It is done for you. Here is an example.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class ActionListenerDemo implements ActionListener {
   JFrame frame	= new JFrame("ActionLIstener Demo");
   JPanel panel	= new JPanel();
 
   public static void main(String[] args) {
	  SwingUtilities.invokeLater(() -> new ActionListenerDemo());
   }
 
   public ActionListenerDemo() {
	  panel.setPreferredSize(new Dimension(400, 200));
	  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	  frame.add(panel);
	  JButton button = new JButton("Button1");
          // listener using method - supported from the beginning.
	  button.addActionListener(this);
          // listener using lambdas - supported in java 8+
	  button.addActionListener(
	        (ae) -> System.out.println("Button pressed - handled from lambda"));
	  panel.add(button);
 
	  frame.pack();
	  frame.setLocationRelativeTo(null); // center on screen
	  frame.setVisible(true);
   }
 
   public void actionPerformed(ActionEvent ae) {
	  System.out.println("Button pressed - handled from method");
   }
}

The code that goes in the listener is what you want the button to do.

Regards,
Jim

Thread: How do I invoke a method to an ActionListener

LinkBack

Thread Tools

Display

How do I invoke a method to an ActionListener

Re: How do I invoke a method to an ActionListener

Similar Threads

API to Invoke the TERMINAL in UBUNTU

Invoke methods

method not passing across actionlistener interface

Timer expires invoke method

how to invoke a method?????

Tags for this Thread