java - 如何在 java 中有效地使用 cardlayout 以便使用各种面板构造函数中的按钮从面板切换

Question

我是使用卡片布局的新手，我有几个关于如何实现它的问题。我首先想知道实现卡片布局的最佳方式，以便我可以在面板之间切换。我的主要问题是如何使用面板构造函数中的按钮在面板之间切换。我今天才开始从事这个项目，所以您会看到一些未完成或没有意义的代码。我首先尝试让我的所有类都扩展 JFrame，但这导致了多个不需要的窗口。如果我能得到一些关于如何有效使用卡片布局以及如何使用我的其他面板构造函数中的按钮切换面板的示例。我尝试使用 cardlayout 仅适用于我在 gui 类中创建的按钮，但这不是我想要的结果。如果可以，请提供帮助，并提前致谢。

这是我的主课。

public class controller{
    public static void main(String[] args){

        new Gui();


    }
}

这是我的 gui 类。

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

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

public class Gui extends JFrame{
    homePage home = new homePage();
    public JPanel loginPanel = new textEmailLog(), 
    registerPanel = new Register(),
    homePanel = new homePage(), viewPanel  = new emailView(),
    loadPanel = new loadEmail(), contentPanel = new JPanel(new CardLayout());
    CardLayout cardLayout = new CardLayout();


    public Gui(){
        super("Email Database Program");
        setSize(700,700);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        contentPanel.setLayout(cardLayout);

        contentPanel.add(loginPanel, "Login");
        contentPanel.add(registerPanel, "Register");
        contentPanel.add(homePanel, "Home");
        contentPanel.add(viewPanel, "View");
        contentPanel.add(loadPanel, "Load");
        this.setContentPane(contentPanel);

        cardLayout.show(contentPanel, "Login");


        setVisible(true);


    }

我的登录面板类

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

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

//panel has been added
public class textEmailLog extends JPanel{
        JPanel logGui = null;
        JButton registerBut, logBut;
        JTextField Login;

    public textEmailLog(){
        //default characteristics
        setSize(700,700);
        setName("Email Database");
        //setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


        //Labels for username and password
        JLabel userLab = new JLabel("Username");
        JLabel pwLab = new JLabel("Password");

        //textfields for username and password
        Login = new JTextField("", 15);
        JPasswordField Password = new JPasswordField("", 15);
        Password.setEchoChar('*');

        //login button that confirms username and password
        logBut = new JButton("Login");
        logBut.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                //needs regex checks prior to logging in 

                if(e.getSource() == logBut){
                    /* Change the panel to the homepage
                    if(Login.getText().equals() && Password.getText().equals()){

                    }
                */  
                    new homePage();
                }


            }
        });

        registerBut = new JButton("Register");
        registerBut.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == registerBut){
                    //Change the panel to the register panel
                }
            }

        });

        //Box layout for organization of jcomponents
        Box verticalContainer = Box.createVerticalBox();
        Box horizontalContainer = Box.createHorizontalBox();
        Box mergerContainer = Box.createVerticalBox();


        //add to panel
        verticalContainer.add(Box.createVerticalStrut(300));//begin relative to the center
        verticalContainer.add(userLab);//Login label and text
        verticalContainer.add(Login);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(pwLab);//password label and text
        verticalContainer.add(Password);
        verticalContainer.add(Box.createVerticalStrut(5));
        horizontalContainer.add(registerBut);//register button
        horizontalContainer.add(Box.createHorizontalStrut(5));
        horizontalContainer.add(logBut);//login button

        //combines both the vertical and horizontal container
        mergerContainer.add(verticalContainer);
        mergerContainer.add(horizontalContainer);
        add(mergerContainer);
        //this.add(logGui);
        setVisible(true);

    }

我的注册面板类

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

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

    //No Panel addition
    public class Register extends JPanel{
            JButton submit, previous;
            JLabel firstLab, lastLab, userLab, passwordLab, repassLab, address, emailAdd, errorLabel;
            JTextField firstText, lastText, userText, addText, emailAddText;
            JPasswordField passwordText, repassText;

        public Register(){
            setSize(700,700);
            //setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


            //register values and their labels and textfields
            firstLab = new JLabel("First Name: ");
            firstText = new JTextField("", 25);
            lastLab = new JLabel("Last Name: ");
            lastText = new JTextField("", 40);
            userLab = new JLabel("Username: ");
            userText = new JTextField("", 25);
            passwordLab = new JLabel("Password: ");
            passwordText = new JPasswordField("", 25);
            passwordText.setEchoChar('*');
            repassLab = new JLabel("Confirm Password");
            repassText = new JPasswordField("", 25);
            repassText.setEchoChar('*');
            address = new JLabel("Address: ");
            addText = new JTextField("", 50);
            emailAdd = new JLabel("Email Address: ");
            emailAddText = new JTextField("", 50);

            //error message for reigstration issues
            errorLabel = new JLabel();
            errorLabel.setForeground(Color.red);

            submit = new JButton("Submit");

            submit.addActionListener(new ActionListener(){

                @SuppressWarnings("deprecation")
                public void actionPerformed(ActionEvent e) {
                    // TODO Auto-generated method stub
                    if(e.getSource() == submit){
                        //confirm with regex methods and if statements that have been created and need to be created
                        if(firstText.getText().length() == 0){
                            errorLabel.setText("*You have not entered a first name!");
                        }else
                        if(lastText.getText().length() == 0){
                            errorLabel.setText("*You have not entered a last name!");
                        }else
                        if(userText.getText().length() == 0){
                            errorLabel.setText("*You have not entered a username!");
                        }else
                        if(passwordText.toString().length() == 0){
                            errorLabel.setText("*You have not entered a Password!");
                        }else
                        if(repassText.toString().length() == 0){    
                            errorLabel.setText("*You have not matched your password!");
                        }
                        if(addText.getText().length() == 0){
                            errorLabel.setText("*You have not entered an address!");
                        }else
                        if(emailAddText.getText().length() == 0){
                            errorLabel.setText("*You have not entered an Email address!");
                        }else
                        if(userText.getText().length() < 8){
                            errorLabel.setText("*Username is too short!");
                        }
                        else
                        if(!(passwordText.toString().matches(repassText.toString()))){
                            errorLabel.setText("Passwords do not match!");
                        }
                        else
                        if(!isValidEmailAddress(emailAddText.getText())){
                            errorLabel.setText("*Invalid Email!");
                        }
                        else
                        if(!isValidAddress(addText.getText())){
                            errorLabel.setText("*Invalid Address!");
                        }
                    }
                }

            });
            //returns to the previous page
            previous = new JButton("Previous Page");
            previous.addActionListener(new ActionListener(){

                public void actionPerformed(ActionEvent e) {
                    // TODO Auto-generated method stub
                    if(e.getSource() == previous){
                        //card.show(login panel);
                    }
                }

            });
            Box verticalContainer = Box.createVerticalBox();
            Box horizontalContainer = Box.createHorizontalBox();
            Box mergerContainer = Box.createVerticalBox();

            verticalContainer.add(Box.createVerticalStrut(150));
            verticalContainer.add(firstLab);
            verticalContainer.add(firstText);
            verticalContainer.add(Box.createVerticalStrut(5));
            verticalContainer.add(lastLab);
            verticalContainer.add(lastText);
            verticalContainer.add(Box.createVerticalStrut(5));
            verticalContainer.add(userLab);
            verticalContainer.add(userText);
            verticalContainer.add(Box.createVerticalStrut(5));
            verticalContainer.add(passwordLab);
            verticalContainer.add(passwordText);
            verticalContainer.add(Box.createVerticalStrut(5));
            verticalContainer.add(repassLab); 
            verticalContainer.add(repassText);  
            verticalContainer.add(Box.createVerticalStrut(5));
            verticalContainer.add(address); 
            verticalContainer.add(addText);
            verticalContainer.add(Box.createVerticalStrut(5));
            verticalContainer.add(emailAdd);
            verticalContainer.add(emailAddText);    
            verticalContainer.add(Box.createVerticalStrut(5));

            //horizontal
            verticalContainer.add(Box.createVerticalStrut(5));
            horizontalContainer.add(submit);
            horizontalContainer.add(Box.createHorizontalStrut(5));
            horizontalContainer.add(previous);

            //merger
            mergerContainer.add(verticalContainer);
            mergerContainer.add(horizontalContainer);

            add(mergerContainer);
            setVisible(true);
        }

        //regex check for valid Email
    public boolean isValidEmailAddress(String email){
            java.util.regex.Pattern p = java.util.regex.Pattern.compile("[A-Za-z0-9._\\%-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}");
            java.util.regex.Matcher m = p.matcher(email);
            return m.matches();

        }
    //regex check for valid Address
    public boolean isValidAddress(String address){
        java.util.regex.Pattern p = java.util.regex.Pattern.compile("\\d{1,3}.?\\d{0,3}\\s[a-zA-Z]{2,30}\\s[a-zA-Z]{2,15}");
        java.util.regex.Matcher m = p.matcher(address);
        return m.matches();

    }
    }

首页面板类

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

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

//NO Panel Yet
@SuppressWarnings("serial")
public class homePage extends JPanel{

        JButton uploadEmail, viewEmail;
    public homePage(){
        setSize(700,700);
        uploadEmail = new JButton("Upload Your Email");
        uploadEmail.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == uploadEmail){
                    new loadEmail();
                }
            }

        });
        viewEmail = new JButton("View An Email");
        viewEmail.addActionListener(new ActionListener(){       

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == viewEmail){
                    new emailView();
                }
            }

        });

        add(uploadEmail);
        add(viewEmail);
        setVisible(true);
    }
}

我的查看电子邮件面板

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

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTable;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class emailView extends JPanel{
        JPanel viewPanel;
        JButton logout, delete, homepage;
        JTable emailList;

        //Cannot be edited or may be in a new panel
        /*
        JLabel fileLab, toLab, fromLab, subjectLab,topicLab, emailLab, notesLab, attachLab;
        JTextField fileText, toText, fromText, subjectText, topicText;
        JTextArea emailText, notesText, attachText;
        */
    public emailView(){
        setSize(700,700);
        setVisible(true);

        emailList = new JTable();
        logout = new JButton("Logout");
        logout.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == logout){
                    new textEmailLog();
                }
            }

        });
        delete = new JButton("Delete");
        delete.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == delete){

                }
            }

        });
        homepage = new JButton("HomePage");
        homepage.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == homepage){
                    new homePage();
                }

            }

        });
        Box horizontalContainer = Box.createHorizontalBox();
        Box verticalContainer = Box.createVerticalBox();
        Box mergerContainer = Box.createVerticalBox();

        horizontalContainer.add(logout);
        horizontalContainer.add(Box.createHorizontalStrut(5));
        horizontalContainer.add(homepage);
        horizontalContainer.add(Box.createHorizontalStrut(5));
        horizontalContainer.add(delete);
        horizontalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(emailList);
        mergerContainer.add(horizontalContainer);
        mergerContainer.add(verticalContainer);
        add(mergerContainer);

        setVisible(true);
    }
}

我的上传邮件面板

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

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


public class loadEmail extends JPanel{
        JPanel loadPanel;
        JLabel fileLab, toLab, fromLab, subjectLab, topicLab, emailLab, notesLab, attachLab;
        JTextField fileText, toText, fromText, subjectText, topicText;
        JTextArea emailText, notesText, attachText; //attachment text will be changed
        JButton cancel, complete, enter;//enter may not be necessary
    public loadEmail(){
        setSize(700,700);

        fileLab = new JLabel("Enter a new File: ");
        fileText = new JTextField();
        enter = new JButton("Enter");
        enter.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == enter){
                    //opens file directory window
                }
            }

        });
        toLab = new JLabel("To: ");
        toText = new JTextField();
        toText.setSize(5, 30);
        fromLab = new JLabel("From: ");
        fromText = new JTextField();
        subjectLab = new JLabel("Subject: ");
        subjectText = new JTextField();
        topicLab = new JLabel("Topic: ");
        topicText = new JTextField();
        emailLab = new JLabel("Email Content: ");
        emailText = new JTextArea();
        notesLab = new JLabel("Comments: ");
        notesText = new JTextArea();
        attachLab = new JLabel("Attachments");
        attachText = new JTextArea();
        cancel = new JButton("Cancel");
        cancel.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == cancel){
                    //dispose page
                }
            }

        });
        complete = new JButton("Complete");
        complete.addActionListener(new ActionListener(){

            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                if(e.getSource() == complete){
                    //store in database, prompt user for new email to enter in other wise return to homepage

                }
            }

        });

        Box verticalContainer = Box.createVerticalBox();
        Box horizontalContainer = Box.createHorizontalBox();
        Box mergerContainer = Box.createVerticalBox();

        verticalContainer.add(fileLab);
        verticalContainer.add(fileText);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(Box.createHorizontalStrut(50));
        verticalContainer.add(enter);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(toLab);
        verticalContainer.add(toText);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(fromLab);
        verticalContainer.add(fromText);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(subjectLab);
        verticalContainer.add(subjectText);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(topicLab);
        verticalContainer.add(topicText);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(emailLab);
        verticalContainer.add(emailText);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(notesLab);
        verticalContainer.add(notesText);
        verticalContainer.add(Box.createVerticalStrut(5));
        verticalContainer.add(attachLab);
        verticalContainer.add(attachText);
        verticalContainer.add(Box.createVerticalStrut(5));

        horizontalContainer.add(cancel);
        horizontalContainer.add(Box.createHorizontalStrut(5));
        horizontalContainer.add(complete);

        mergerContainer.add(verticalContainer);
        mergerContainer.add(horizontalContainer);
        add(mergerContainer);
        setVisible(true);

    }

}

Answer 1

简短的回答是不要。这样做的原因是您最终不得不将父容器和 CardLayout 暴露给您的所有子组件，这不仅将您的应用程序的某些部分暴露给潜在的滥用，而且它与导航紧密耦合，使其变得困难将来添加/删除步骤...

更好的解决方案是设计某种 Controller 接口(interface)，它定义每个 View 可以做什么(例如showHome、nextView , previousView), 然后你可以将这个接口(interface)的实现传递给每个 View 。然后，每个 View 都将使用此接口(interface)根据需要请求更改。

Controller 会知道当前 View 、主视图以及如何根据需要在某些 View (下一个/上一个)之间移动。

更新了简单的例子

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.ContainerAdapter;
import java.awt.event.ContainerEvent;
import java.awt.event.HierarchyEvent;
import java.awt.event.HierarchyListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class AllYouViewBelongToMe {

    public static void main(String[] args) {
        new AllYouViewBelongToMe();
    }

    public AllYouViewBelongToMe() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public interface ViewContoller {

        public void goHome();

        public void nextView();

        public void previousView();

    }

    public static class DefaultViewController implements ViewContoller {

        public static final String HOME = "home";

        private Component currentView = null;
        private List<Component> views;
        private Map<Component, String> mapNames;

        private Container parent;
        private CardLayout cardLayout;

        public DefaultViewController(Container parent, CardLayout cardLayout) {
            this.parent = parent;
            this.cardLayout = cardLayout;
            views = new ArrayList<>(25);
            mapNames = new HashMap<>(25);
        }

        public CardLayout getCardLayout() {
            return cardLayout;
        }

        public Container getParent() {
            return parent;
        }

        public void addView(Component comp, String name) {
            if (!HOME.equals(name)) {
                views.add(comp);
            }
            mapNames.put(comp, name);
            getParent().add(comp, name);
        }

        public void removeView(Component comp, String name) {
            views.remove(comp);
            mapNames.remove(comp);
            getParent().remove(comp);
        }

        @Override
        public void goHome() {
            currentView = null;
            getCardLayout().show(getParent(), HOME);
        }

        @Override
        public void nextView() {
            if (views.size() > 0) {
                String name = null;
                if (currentView == null) {
                    currentView = views.get(0);
                    name = mapNames.get(currentView);
                } else {
                    int index = views.indexOf(currentView);
                    index++;
                    if (index >= views.size()) {
                        index = 0;
                    }
                    currentView = views.get(index);
                    name = mapNames.get(currentView);
                }
                getCardLayout().show(getParent(), name);
            }
        }

        @Override
        public void previousView() {
            if (views.size() > 0) {
                String name = null;
                if (currentView == null) {
                    currentView = views.get(views.size() - 1);
                    name = mapNames.get(currentView);
                } else {
                    int index = views.indexOf(currentView);
                    index--;
                    if (index < 0) {
                        index = views.size() - 1;
                    }
                    currentView = views.get(index);
                    name = mapNames.get(currentView);
                }
                getCardLayout().show(getParent(), name);
            }
        }

    }

    public class TestPane extends JPanel {

        public TestPane() {
            setLayout(new BorderLayout());

            CardLayout cardLayout = new CardLayout();
            JPanel view = new JPanel(cardLayout);

            final DefaultViewController controller = new DefaultViewController(view, cardLayout);
            controller.addView(createPane("home"), DefaultViewController.HOME);
            controller.addView(createPane("Page #1"), "View1");
            controller.addView(createPane("Page #2"), "View2");
            controller.addView(createPane("Page #3"), "View3");
            controller.addView(createPane("Page #4"), "View4");

            controller.goHome();

            JPanel controls = new JPanel();
            JButton btnPrev = new JButton("<");
            JButton btnHome = new JButton("Home");
            JButton btnNext = new JButton(">");

            controls.add(btnPrev);
            controls.add(btnHome);
            controls.add(btnNext);

            btnNext.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    controller.nextView();
                }
            });
            btnPrev.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    controller.previousView();
                }
            });
            btnHome.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    controller.goHome();
                }
            });

            add(view);
            add(controls, BorderLayout.SOUTH);

        }

        protected JPanel createPane(String name) {

            JPanel panel = new JPanel(new GridBagLayout());
            panel.add(new JLabel(name));

            return panel;

        }
    }

}