CODEWITHSUNDEEP
javaswingactionactionlistener
user2634655
user2634655

Reputation:

Java Listener- not listening

I'm trying to compile this code (below) but I keep receiving an error message stating

Multiple markers at this line

  • The type qq must implement the inherited abstract method ActionListener.actionPerformed(ActionEvent)
  • The serializable class qq does not declare a static final serialVersionUID field of type long

I'm still quite new to Java and I can't really figure out what's going on, would you all happen to have any insight onto how I might rectify this unfortunate situation?

public class qq extends JFrame implements ActionListener, ItemListener {

    // many fields here

    public qq() {
        // components initializing
        // other code for window closing etc.
    }

    // actionPerformed is ActionListener interface method
    // which responds to action event of selecting
    // combo box or radio button
    public void ationPerformed(ActionEvent e){
        if (e.getSource() instanceof JComboBox){
            System.out.println("Customer shops: " + freqButton.getSelectedItem());
        }
        else if (e.getSource() instanceof JRadioButton){
            if (age1.isSelected() ){
                System.out.println("Customer is under 20");
            }
            else if (age2.isSelected() ){
                System.out.println("Customer is 20 - 39");
            }
            else if (age3.isSelected() ){
                System.out.println("Customer is 39 - 59");
            }
            else if (age4.isSelected() ){
                System.out.println("Customer is over 60");
            }
        }
    }

    // itemStateChanged is ItemListener interface method
    // which responds to item event of clicking checkbox
    public void itemStateChanged (ItemEvent e){
        if (e.getSource() instanceof JCheckBox){
            JCheckBox buttonLabel = (JCheckBox)
                    e.getItemSelectable();
            if (buttonLabel == tradeButton){
                if (e.getStateChange() == e.SELECTED) {
                    System.out.println("Customer is trade");
                }
                else
                {
                    System.out.println("Customer is not trade");
                }
            }
        }
    }

    public static void main(String args[]) {
        qq cd = new qq();
        // other code setting up the window
    }

}

Upvotes: 1

Views: 387

Answers (3)

vishnu viswanath
vishnu viswanath

Reputation: 3854

You have a typo in your method name ationPerformed it should be actionPerformed

Upvotes: 2

Sinkingpoint
Sinkingpoint

Reputation: 7634

You need to implement the actionPerformed method. You seem to have implemented it as ationPerformed thus, you need to fix that spelling. Because you have not correctly implemented the interface, you cannot use the class as an ActionListener.

As to the serializable issue - this is to do with the fact that JFrame implements the Serializable interface, which requires a serialVersionUID. You can compile without one, but the IDE will complain. [For more info, see here]

As a side note, generally you don't want to extend JFrame, instead use an instance in your class.

Upvotes: 2

piet.t
piet.t

Reputation: 11921

Corrrect your typo in public void ationPerformed(ActionEvent e) and add the missing "c" in "action", this will take care of the error message.

You can ignore the warning about the serialVersionUID for, come back to that later when you learn more about Serialization.

Upvotes: 2

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