我可以将ActionListener添加到jFrame中的按钮，并将actionPerformed方法添加到其他类中吗？

Question

I have a jFrame where a user enters their data and a controller class where I would like to enter that data into a new object. At the moment I have added a listener to the button in the jFrame but cannot get it to recognise the actionPerformed method in the controller class.

The 'this' part of the listener is stating that it is leaking into the constructor and the class itself is stating:

"CreateAccountGUI is not abstract and does not override abstract method actionPerformed(actionEvent) in Action Listener"

I do have other buttons but they use the default constructor provided when double clicking the controls.

Heres the code for the jFrame constructor:

public class CreateAccountGUI extends javax.swing.JFrame implements ActionListener{

/**
 * Creates new form CreateAccountGUI
 */
public CreateAccountGUI() {
    initComponents();
    cboAccountType.setVisible(false);
    lblAccountType.setVisible(false);
    btnCreateAccount.addActionListener(this);
} 

And heres the code I currently have in the class where I want the actionPerformed method to reside:

public class AccountStrategyController implements ActionListener, Observer{

private CreateAccountGUI view = null;

public void setView(CreateAccountGUI view){
    this.view = view;
    view.setVisible(true);//Show the account creation form
}

@Override
public void actionPerformed(ActionEvent e) {

}

I don't have any errors in this class at the moment.

I've looked online and it seems that you can have the added listener and the actionPerformed in different classes, I just can't seem to get my head round it.

Any help is really appreciated :)

Answer 1

You could do:

public class CreateAccountGUI extends javax.swing.JFrame {

    public CreateAccountGUI() {
        /**/
        JButton btnCreateAccount = new JButton("Create");
        AccountStrategyController controller = new AccountStrategyController();
        controller.setView(this);
        btnCreateAccount.addActionListener(controller);
    }
}

class AccountStrategyController implements ActionListener{

    private CreateAccountGUI view = null;

    public void setView(CreateAccountGUI view){
        this.view = view;
        view.setVisible(true);//Show the account creation form
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        //respond to button click 
    }
}

Or better:

public class CreateAccountGUI extends javax.swing.JFrame {

    public CreateAccountGUI() {
        /**/
        JButton btnCreateAccount = new JButton("Create");
        AccountStrategyController controller = new AccountStrategyController();
        controller.setView(this);
        btnCreateAccount.addActionListener(controller.createAccountListener());
    }
}

class AccountStrategyController{

    private CreateAccountGUI view = null;

    public void setView(CreateAccountGUI view){
        this.view = view;
        view.setVisible(true);//Show the account creation form
    }

    public  ActionListener createAccountListener(){     
        return new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                //respond to button click 
            }
        };
    }   
}

createAccountListener can be written using lambdas:

public  ActionListener createAccountListener(){     
    return e -> {
        //respond to button click 
    };
}   

Answer 2

I would recommend to do this: 1. First of all, as you are working with an MVC (model-view-controller) structure, you must differentiate files. For example, your first code is a class that extends from a JFrame. This class goes to the view package and can't implement ActionListener. ActionListener is for controllers. To link JFrame class with controllers you will have to create a method in the 'CreateAccountGUI' like this:

public void registerControllers(AccountStrategyController controller) {
    jButton.setActionCommand("JBUTTON");
    jButton.addActionListener(controller);
}

Then, in the actionPerformed() method you must write this:

public void actionPerformed(ActionEvent e) {
    switch(e.getActionCommand()) {
        case "JBUTTON":
            //Your code goes here
            break;
    }
}

And to make this work, in the Main class where you init the GUI you must write something like this:

public static void main(String[] args) {
    // Elements de la interfície gràfica
    CreateAccountGUI gui = new CreateAccountGUI();
    AccountStrategyController asc = new AccountStrategyController();
    gui.registerControllers(asc);   
}

Hope it helps you