如何在java.swing JTextField中存储字符串或整数？

Question

Hello I am working on this project to store student names and record their grades. I have the entire program mapped out and all I need to do now is record the integers and strings from the user input and call it from different classes. I am having trouble with this. Do I use an array? How do I call from another class? Thank you.

    package gradebook;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.util.Scanner;
import java.awt.event.ActionEvent;
import javax.swing.JTextArea;

public class Student extends JFrame {
    private JFrame studentFrame;
    private JPanel contentPane;
    private JTextField studentNameTextField;
    protected Component frame;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Student frame = new Student();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public Student() {

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JLabel gradebookLabel = new JLabel("Gradebook");
        gradebookLabel.setBounds(189, 6, 68, 16);
        contentPane.add(gradebookLabel);

        JLabel lblPleaseEnterThe = new JLabel("Please enter the student name");
        lblPleaseEnterThe.setBounds(130, 105, 194, 16);
        contentPane.add(lblPleaseEnterThe);

        studentNameTextField = new JTextField("Enter here");
        String stdname = studentNameTextField.getText();
        studentNameTextField.setBounds(130, 133, 194, 26);
        contentPane.add(studentNameTextField);
        studentNameTextField.setColumns(10);

        JButton continueButton = new JButton("Continue");
        continueButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent a) {
                if(continueButton.isEnabled()){
                Student.this.dispose();
                    Student studentScreen = new Student();
                    studentScreen.dispose();

                    AddGrades addGradesScreen = new AddGrades();
                    addGradesScreen.setVisible(true);


                }
            }
        });
        continueButton.setBounds(327, 243, 117, 29);
        contentPane.add(continueButton);

        JButton cancelButton = new JButton("Cancel");
        cancelButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent a) {


                if(cancelButton.isEnabled()){




                    MainScreen mainScreenScreen = new MainScreen();
                    mainScreenScreen.setVisible(true);
                    contentPane.setVisible(false);
                    contentPane.disable();


                }
            }
        });


        cancelButton.setBounds(207, 243, 117, 29);
        contentPane.add(cancelButton);
    }

    private void initizalize() {
        // TODO Auto-generated method stub

    }
}

Is it something along the lines of this?

studentNameTextField = new JTextField("Enter here");
        String stdname = studentNameTextField.getText();

I know this would be storing it but how do I call that in a different class so I can make it appear on a different Frame?

Update: Okay so I've done this

Student frame = new Student();
        String stdname = frame.studentNameTextField.getText();
        JLabel addgradesLabel = new JLabel("Add grades for" + frame.studentNameTextField);
        addgradesLabel.setBounds(139, 34, 167, 29);
        contentPane.add(addgradesLabel);

And it's still not working. I believe I'm not implementing this correctly. I'm trying to title the label with what the user inputs for the name. So it would but "Add grades for" + stdname But it's not calling it correctly. How can I fix this?

Here is my code from the AddStudentName class

studentNameTextField = new JTextField();
        studentNameTextField.setBounds(130, 133, 194, 26);
        contentPane.add(studentNameTextField);
        studentNameTextField.setColumns(10);

        JButton continueButton = new JButton("Continue");
        continueButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent a) {
                if(continueButton.isEnabled()){
                Student.this.dispose();
                    Student studentScreen = new Student();
                    studentScreen.dispose();


                    AddGrades addGradesScreen = new AddGrades();
                    addGradesScreen.setVisible(true);




                }
            }
        });

What should I add here to save the input that the user is inputting into the JTextField? Thanks for the help

Here's the full code for the classes:

package gradebook;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.util.Scanner;
import java.awt.event.ActionEvent;
import javax.swing.JTextArea;

public class Student extends JFrame {
    private JFrame studentFrame;
    private JPanel contentPane;
    public JTextField studentNameTextField;
    protected Component frame;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Student frame = new Student();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public Student() {

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JLabel gradebookLabel = new JLabel("Gradebook");
        gradebookLabel.setBounds(189, 6, 68, 16);
        contentPane.add(gradebookLabel);

        JLabel lblPleaseEnterThe = new JLabel("Please enter the student name");
        lblPleaseEnterThe.setBounds(130, 105, 194, 16);
        contentPane.add(lblPleaseEnterThe);


        JTextField studentNameTextField = new JTextField();

        studentNameTextField.setBounds(130, 133, 194, 26);
        contentPane.add(studentNameTextField);
        studentNameTextField.setColumns(10);

        JButton continueButton = new JButton("Continue");
        continueButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent a) {
                if(continueButton.isEnabled()){

                    Student studentScreen = new Student();
                    studentScreen.dispose();

                    AddGrades addGradesScreen = new AddGrades();
                    addGradesScreen.setVisible(true);



                }
            }
        });


        continueButton.setBounds(327, 243, 117, 29);
        contentPane.add(continueButton);

        JButton cancelButton = new JButton("Cancel");
        cancelButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent a) {


                if(cancelButton.isEnabled()){




                    MainScreen mainScreenScreen = new MainScreen();
                    mainScreenScreen.setVisible(true);
                    contentPane.setVisible(false);
                    contentPane.disable();


                }
            }
        });


        cancelButton.setBounds(207, 243, 117, 29);
        contentPane.add(cancelButton);
    }

    private void initizalize() {
        // TODO Auto-generated method stub

    }
}

and:

package gradebook;

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class AddGrades extends JFrame {

    private JPanel contentPane;
    private JTextField Assignment1;
    private JTextField Assignment2;
    private JTextField Assignment3;
    private JTextField Assignment4;
    private JLabel testsLabel;
    private JTextField Test1;
    private JTextField Test2;
    public JTextField Test3;
    public JTextField Test4;

    /**
     * Launch the application.
     */
    public JFrame frame;
    public JButton continueButton;
    public JButton exitButton;
    public static void main(String[] args) {
        AddGrades frame = new AddGrades();
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    AddGrades frame = new AddGrades();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public AddGrades() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JLabel gradebookLabel = new JLabel("Gradebook");
        gradebookLabel.setBounds(189, 6, 68, 16);
        contentPane.add(gradebookLabel);


        JLabel addgradesLabel = new JLabel("Add grades for" + stdname);
        addgradesLabel.setBounds(139, 34, 167, 29);
        contentPane.add(addgradesLabel);

        JLabel assignmentsLabel = new JLabel("Assignments:");
        assignmentsLabel.setBounds(19, 75, 86, 16);
        contentPane.add(assignmentsLabel);

        Assignment1 = new JTextField();
        Assignment1.setBounds(54, 91, 130, 26);
        contentPane.add(Assignment1);
        Assignment1.setColumns(10);

        Assignment2 = new JTextField();
        Assignment2.setBounds(54, 129, 130, 26);
        contentPane.add(Assignment2);
        Assignment2.setColumns(10);

        Assignment3 = new JTextField();
        Assignment3.setBounds(54, 167, 130, 26);
        contentPane.add(Assignment3);
        Assignment3.setColumns(10);

        Assignment4 = new JTextField();
        Assignment4.setBounds(54, 205, 130, 26);
        contentPane.add(Assignment4);
        Assignment4.setColumns(10);

        testsLabel = new JLabel("Tests:");
        testsLabel.setBounds(243, 75, 38, 16);
        contentPane.add(testsLabel);

        Test1 = new JTextField();
        Test1.setBounds(262, 91, 130, 26);
        contentPane.add(Test1);
        Test1.setColumns(10);

        Test2 = new JTextField();
        Test2.setBounds(262, 129, 130, 26);
        contentPane.add(Test2);
        Test2.setColumns(10);

        Test3 = new JTextField();
        Test3.setBounds(262, 167, 130, 26);
        contentPane.add(Test3);
        Test3.setColumns(10);

        Test4 = new JTextField();
        Test4.setBounds(262, 205, 130, 26);
        contentPane.add(Test4);
        Test4.setColumns(10);

        continueButton = new JButton("Continue");
        continueButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent a){
                if (continueButton.isEnabled()){

                    MainScreen mainScreenScreen = new MainScreen();
                    mainScreenScreen.setVisible(true);

                }


            }
        });
        continueButton.setBounds(327, 243, 117, 29);
        contentPane.add(continueButton);

        exitButton = new JButton("Exit");

        exitButton.setBounds(208, 243, 117, 29);
        contentPane.add(exitButton);
    }
}

I'm trying to take the input from the JTextField

JTextField studentNameTextField = new JTextField();

and set it on the label

JLabel addgradesLabel = new JLabel("Add grades for" + stdname);

Where stdname would be the user input from the JTextField.

Now I'm getting errors from

public static void main(String[] args) {
        AddGrades frame = new AddGrades();
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    AddGrades frame = new AddGrades();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

AddGrades frame = new AddGrades(); gives me error Add argument to match AddGrades(String)

The constructor AddGrades() is undefined

Answer 1

Edit: The best way to do this is to pass an argument to your newly created AddGrades class. See below:

public AddGrades(String stdname) {
    JLabel addgradesLabel = new JLabel("Add grades for " + stdname);
}

You will need to modify your code to pass a string to your AddGrades class wherever you create it:

JButton continueButton = new JButton("Continue");
continueButton.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent a) {
        if(continueButton.isEnabled()){

            Student studentScreen = new Student();
            studentScreen.dispose();

            AddGrades addGradesScreen = new AddGrades(studentNameTextField.getText());
            addGradesScreen.setVisible(true);
        }
    }
});

That worked for me - I downloaded your code and tested it.

Answer 2

JSpinner or JFormattedTextField would be my first thought, but if you can't do that then you could use Integer.parseInt to parse a String to int and a NumberFormat to format the numbers to String s

Maybe have a look at How to Use Spinners and How to Use Formatted Text Fields for starters

I know this would be storing it but how do I call that in a different class so I can make it appear on a different JFrame?

That's a open question with little context. You might use some kind of "model" which represented one or more Student values; you might use a Observer Pattern to allow the editor to generate events to interested parties which would tell them that something has changed; you might use a Model-View-Controller ; you might use a modal dialog and when it's closed, ask the editor for the values via getters.

Have a look at How to Make Dialogs for more details

One of things you want to keep in mind is "responsibility" and "encapsulation". You don't want outside parties to have uncontrolled access into your editor or model, this could allow them to modify the state in an uncontrolled way leading to inconsistencies in your data or UI.

You need to decide who is actually responsible for modifying the state of the model. There's no "right" answer, for example, you could have the editor either be capable of editing existing student objects or creating new ones based on how it's configured, equally, you could also have the editor be "dumb" and simply use setters to setup the editor and getters to get the values.

There are lots of options available to you, which you would use would be based on the context in which you want to use it. My gut feeling is start with an observer pattern and a modal dialog.