JButton events

Hi,
Im still relatively new to GUI. Ive seen a lot of tutorials out there, but none of them really explain what im doing, and just show examples. Im trying to learn how to make a JButton do something when you click on it.
Ive seen few examples that say to to make a new function like this:

Code :

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private void jButton1ActionPerformed(java.awt.event.ActionEvent evt){

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but i dont really understand how that helps. Could someone tell me how to give a JButton a function, and explain what is happening in the code.
Thanks
Pottsie

Have you worked through this?
Lesson: Writing Event Listeners (The Java™ Tutorials > Creating a GUI With JFC/Swing)

Ive looked at it, but i havent been able to do what theyve done. I try this:

Code :

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import javax.swing.*;
import java.awt.*;
 
public class LessonOne {
 
    public static void main(String[] args) {
        GridLayout myLayout = new GridLayout(2, 3);
        JFrame frame = new JFrame( "Working with JButtons");
        frame.setSize(100,100);        
        JPanel myPanel = new JPanel();
        myPanel.setLayout(myLayout);
        JButton newButton = new JButton ("Click Me"); 
        newButton.addActionListener(this);
        newButton.setToolTipText("This button does nothing...");
        myPanel.add(newButton);
        frame.getContentPane().add(myPanel);
        frame.setVisible(true);
 
    }
 
     public void actionPerformed(ActionEvent e) {
        Toolkit.getDefaultToolkit().beep();
    }
}

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and i get the error "cannot find symbol - class ActionEvent"

You haven't told javac where to look for the class ActionEvent with an import statement. Have a look at the list of imports at the top of the Beeper.java example.

http://download.oracle.com/javase/tu...nts/intro.html
http://download.oracle.com/javase/tu...ts/Beeper.java

Do i have to write the code the way they did, writing the class as an extension of JPanel? I added in the imports they had, and i get "non-static variable this cannot be referenced from a static context"...

Quote:

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Originally Posted by pottsiex5

Do i have to write the code the way they did, writing the class as an extension of JPanel? I added in the imports they had, and i get "non-static variable this cannot be referenced from a static context"...

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You don't need to extend JPanel, but you do need an instance (I'm assuming of ActionListener) to pass into the method. Do that by implementing ActionListener in a class you actually instantiate or by using an anonymous inner class.

Hey,
So i put implement ActionListener into the class line like this:

Code :

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public static void main implements ActionListener (String[] args) {

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but i get a red line under "main" and "implements ActionListener (String[] args)". I also tried putting it after (String[] args) but it gave me a red line under implements.

So what i have all together is:

Code :

---

import javax.swing.*;
import java.awt.*;
 
public class LessonOne {
 
	public static void main (String[] args) implements ActionListener {
		GridLayout myLayout = new GridLayout(2, 3);
		JFrame frame = new JFrame( "Hello World");
		frame.setSize(100,100);
		JPanel myPanel = new JPanel();
		myPanel.setLayout(myLayout);
		JButton button = new JButton ("Hello");
		startButton.addActionListener(this);
		myPanel.add(button);
		frame.getContentPane().add(myPanel);
		frame.setVisible(true);
 
	}
 
	public void actionPerformed(ActionEvent a) {
			System.out.println("hello");
	}
 
}

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Well, that's not valid syntax, and that's not what I suggested. Recommended reading: Lesson: Writing Event Listeners (The Java™ Tutorials > Creating a GUI With JFC/Swing)

Edit- I see Sean4u already gave you this advice.

I cant find any syntax other than
"public class ClassName extends JPanel
implements ActionListener {"
which doesnt help me...

You could use an anonymous inner class, as stated above. Did you do any googling of that? Something like:

Code java:

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ActionListener al = new ActionListener(){
   public void actionPerformed(ActionEvent e){
      System.out.println("clicked");
   }
}
 
button.addActionListener(al);

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