java - 如何访问另一个类中的 JTextField 内容

Question

登录类中初始化的Jtextfield需要在Clayout中访问 当单击登录按钮时。我想将 JTextfield 的数据与某些字符串进行比较并执行一些操作。
但它正在经历异常

“TextField未定义”任何人都可以帮助我吗

import java.awt.CardLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.JLabel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

public class CLayout {

    JFrame frame = new JFrame("CardLayout demo");
    JPanel panelCont = new JPanel();
    JPanel log = new LoginView();
    JPanel Img = new ImageGallery();
    CardLayout cl = new CardLayout();

    public CLayout() {
        final String user = CLayout.getFieldText();
        panelCont.setLayout(cl);
        log.setLayout(new BoxLayout(log, BoxLayout.PAGE_AXIS));
        Img.setLayout(new BoxLayout(Img, BoxLayout.PAGE_AXIS));
        JButton loginButton = new JButton("login");
        JButton registerButton = new JButton("register");
        JTextField field2 = new JTextField(20);
        loginButton.setBounds(10, 80, 80, 25);
        log.add(loginButton);
        registerButton.setBounds(180, 80, 80, 25);
        log.add(registerButton);
        panelCont.add(log, "1");
        panelCont.add(Img, "2");
        cl.show(panelCont, "1");
        loginButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                if (user == "imagegallery") {
                    cl.show(panelCont, "2");
                }
            }
        });
        registerButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                cl.show(panelCont, "1");
            }
        });
        frame.add(panelCont);
        frame.setSize(800, 600);
        frame.setTitle("     Image Gallery    ");
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new CLayout();
            }
        });
    }
}

class ImageGallery extends JPanel {

    private ImageIcon myImage1 = new ImageIcon("Chrysanthemum.jpg");
    private ImageIcon myImage2 = new ImageIcon("Desert.jpg");
    private ImageIcon myImage3 = new ImageIcon("Jellyfish.jpg");
    private ImageIcon myImage4 = new ImageIcon("principal.jpg");
    private ImageIcon myImage5 = new ImageIcon("student.jpg");
    private ImageIcon myImage6 = new ImageIcon("library.jpg");
    private ImageIcon myImage7 = new ImageIcon("sports.jpg");
    private ImageIcon myImage8 = new ImageIcon("class.jpg");
    JPanel ImageGallery = new JPanel();
    private ImageIcon[] myImages = new ImageIcon[8];
    private int curImageIndex = 0;

    public ImageGallery() {
        ImageGallery.add(new JLabel(myImage1));
        myImages[0] = myImage1;
        myImages[1] = myImage2;
        myImages[2] = myImage3;
        myImages[3] = myImage4;
        myImages[4] = myImage5;
        myImages[5] = myImage6;
        myImages[6] = myImage7;
        myImages[7] = myImage8;
        add(ImageGallery, BorderLayout.CENTER);
        JButton PREVIOUS = new JButton("Previous");
        JButton FILE = new JButton("File");
        JButton EDIT = new JButton("Edit");
        JButton NEXT = new JButton("Next");
        JButton HELP = new JButton("Help");
        JPanel Menu = new JPanel();
        Menu.setLayout(new GridLayout(1, 5));
        Menu.add(FILE);
        Menu.add(EDIT);
        Menu.add(PREVIOUS);
        Menu.add(NEXT);
        Menu.add(HELP);
        add(Menu, BorderLayout.NORTH);
        //register listener
        PreviousButtonListener PreviousButton = new PreviousButtonListener();
        NextButtonListener NextButton = new NextButtonListener();
        //add listeners to corresponding componenets 
        PREVIOUS.addActionListener(PreviousButton);
        NEXT.addActionListener(NextButton);
    }

    class PreviousButtonListener implements ActionListener {

        public void actionPerformed(ActionEvent e) {
            if (curImageIndex > 0 && curImageIndex <= 5) {
                ImageGallery.remove(0);
                curImageIndex = curImageIndex - 1;
                ImageIcon TheImage = myImages[curImageIndex];
                ImageGallery.add(new JLabel(TheImage));
                ImageGallery.validate();
                ImageGallery.repaint();
            } else {
                ImageGallery.remove(0);
                ImageGallery.add(new JLabel(myImage6));
                curImageIndex = 5;
                ImageGallery.validate();
                ImageGallery.repaint();
            }
        }
    }

    class NextButtonListener implements ActionListener {

        public void actionPerformed(ActionEvent e) {

            if (curImageIndex >= 0 && curImageIndex < 5) {
                ImageGallery.remove(0);
                curImageIndex = curImageIndex + 1;
                ImageIcon TheImage = myImages[curImageIndex];
                ImageGallery.add(new JLabel(TheImage));
                ImageGallery.validate();
                ImageGallery.repaint();
            } else {
                ImageGallery.remove(0);
                ImageGallery.add(new JLabel(myImage1));
                curImageIndex = 0;
                ImageGallery.validate();
                ImageGallery.repaint();
            }

        }
    }
}

class LoginView extends JPanel {

    JLabel userLabel = new JLabel("User");
    JTextField userText = new JTextField(20);
    JLabel passwordLabel = new JLabel("Password");
    JPasswordField passwordText = new JPasswordField(20);

    public LoginView() {
        userLabel.setBounds(10, 10, 80, 25);
        add(userLabel);
        userText.setBounds(100, 10, 160, 25);
        add(userText);
        passwordLabel.setBounds(10, 40, 80, 25);
        add(passwordLabel);
        passwordText.setBounds(100, 40, 160, 25);
        add(passwordText);
    }

    String getFieldText()
       return userText.getText().toString();
}

Answer 1

你可以为它编写一个 setter/getter :

public String getTextFromTextField(){
  return jTextField1.getText();
}

并简单地调用它。