Java GUI 只接受某些名称

Question

I'm currently working on a GUI where you enter your name and it tells you whether or not it has been accepted. Say that if the names "John" or "Jane" are entered then you get a "Verified" message or "Unverified" message if you type any other name. Here's what I have so far, just really unsure how to add the IF statement for detecting the certain names. Thanks.

NamePrompt.java

import java.awt.BorderLayout;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class NamePrompt extends JFrame{

    private static final long serialVersionUID = 1L;

    String name;

    public NamePrompt(){

        setLayout(new BorderLayout());

        JLabel enterYourName = new JLabel("Enter Your Name Here:");
        JTextField textBoxToEnterName = new JTextField(21);
        JPanel panelTop = new JPanel();
        panelTop.add(enterYourName);
        panelTop.add(textBoxToEnterName);

        JButton submit = new JButton("Submit");
        submit.addActionListener(new SubmitButton(textBoxToEnterName));
        JPanel panelBottom = new JPanel();
        panelBottom.add(submit);

        //Add panelTop to JFrame
        add(panelTop, BorderLayout.NORTH);
        add(panelBottom, BorderLayout.SOUTH);

        //JFrame set-up
        setTitle("Name Prompt Program");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        pack();
        setLocationRelativeTo(null);

   }

    public static void main(String[] args) {
        NamePrompt promptForName = new NamePrompt();
        promptForName.setVisible(true); 
    }

}

SubmitButton.java

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

import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;


public class SubmitButton implements ActionListener {

    JTextField nameInput;

    public SubmitButton(JTextField textfield){
        nameInput = textfield;
    }

    @Override
    public void actionPerformed(ActionEvent submitClicked) {
        Component frame = new JFrame();
        JOptionPane.showMessageDialog(frame , "You've Submitted the name " + nameInput.getText() + " which is allowed.");
    }


}

Answer 1

As mentioned in another answer, this should be handled in the actionPerformed method. However, going based on what you've presented to the community, here's something that should work;

if the names are case sensitive, your modification would be as such:

public SubmitButton(JTextField textfield){
    nameInput = textfield;
    if (nameInput.equals("InsertCaseSensitiveName")) {
        //TODO: Verified Name
    } else {
        //TODO: Unverified Name
    }
}

if case insensitive:

public SubmitButton(JTextField textfield){
    nameInput = textfield;
    if (nameInput.equalsIgnoreCase("InsertCaseSensitiveName")) {
        //TODO: Verified Name
    } else {
        //TODO: Unverified Name
    }
}

To use a list:

//initialize your list (formed so backwards compatible)
List<String> valid = new java.util.concurrent.CopyOnWriteArrayList<String>();
//Within a function, add all names to the list in lowercase (java.lang.String.toLowerCase())

    public SubmitButton(JTextField textfield){
        nameInput = textfield;
        if (valid.contains(nameInput.toLowerCase()) {
            //TODO: Verified Name
        } else {
            //TODO: Unverified Name
        }
    }

References:

conditional if statements

java.lang.String.equals

java.lang.String.equalsIgnoreCase

java.lang.String.toLowerCase

java.util.List

java.util.concurrent.CopyOnWriteArrayList

Answer 2

The actionPerformed method is called after clicking the submit button.

public void actionPerformed(ActionEvent submitClicked) {
    Component frame = new JFrame();
    JOptionPane.showMessageDialog(frame , "You've Submitted the name " + nameInput.getText() + " which is allowed.");

    // You can store the value of whatever the user enters.
    String inputName = nameInput.getText();

    // And add the if statements:
    if(inputName.equals("John") {
        JOptionPane.showMessageDialog(frame, "Verified");
    }
}

Alternatively you can create a List of Strings that contains all the names that is accepted. Example:

List<String> acceptedNames = Arrays.asList(new String[]{"John", "Jane"});
// and check
if acceptedNames.contains(inputName) {
    // verified.
}