我是 Java Swing 的新手,我正在尝试学习如何关闭一帧而不使用按钮关闭另一帧。例如,我有一个frame1/窗口,其中只有一个名为“登录”的按钮。单击登录按钮后,会出现另一个窗口frame2。在第 2 帧上,我只有一个示例 JLabel“Hello And Welcome”,按钮名为“注销”。我希望能够单击框架 2 上的“注销”按钮,框架 2 窗口应该关闭,但框架 1 窗口显示仍然打开。我尝试过 setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE),但只有当我单击 Frame2 窗口右上角的 x 图标时它才有效。有谁知道单击按钮时关闭框架的方法吗?
public class Frame1 extends JFrame implements ActionListener{
private static JButton login = new JButton("Login");
private static JFrame f = new JFrame("Login");
Frame1(){
f.setSize(1000,750);
f.setLocation(750, 250);
login.setBounds(250, 350, 150, 30);
f.add(login);
f.setLayout(null);
f.setVisible(true);
login.addActionListener(this);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent e){
if (e.getSource() == login){
Frame2.frame2windown();
}
}
public static void main(String [] args){
Frame1 login1 = new Frame1();
}
}
public class Frame2 extends JFrame implements ActionListener{
private static JButton logout = new JButton("Logout");
private static JLabel jb1 = new JLabel ("Hello And Welcome");
private static JFrame f = new JFrame("Log Out");
Frame2(){
f.setSize(1000,750);
f.setLocation(750, 250);
jb1.setBounds(250, 150, 350, 30);
logout.setBounds(250, 350, 150, 30);
f.add(logout);
f.add(jb1);
f.setLayout(null);
f.setVisible(true);
logout.addActionListener(this);
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}
public void actionPerformed(ActionEvent a){
if(a.getSource() == logout){
dispose();
WindowEvent closeWindow = new WindowEvent(this, JFrame.DISPOSE_ON_CLOSE);
Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(closeWindow);
}
}
public static void frame2windown(){
Frame2 f2 = new Frame2();
}
}
因此,您需要尝试和学习一大堆概念。
JFrame
)。您不会向它们添加任何新功能;它们是复杂的复合组件;您将自己锁定在单个用例中(如果您想将 UI 包含在另一个 UI 中或使用对话框而不是框架,会发生什么?!)布局管理器是一个绝对必需的功能,您确实需要花时间来学习它们,请参阅在容器内布局组件了解更多详细信息。
所以,这是一个使用
CardLayout
和基本“观察者模式”的快速示例,它可以解耦和分离责任。
import java.awt.CardLayout;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.EventListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame();
frame.add(new NavigationPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class NavigationPane extends JPanel {
protected enum NavigationTarget {
LOGIN, MAIN;
}
private LoginPane loginPane;
private MainPane mainPane;
private CardLayout cardLayout;
public NavigationPane() {
cardLayout = new CardLayout();
setLayout(cardLayout);
loginPane = new LoginPane();
loginPane.addLoginListener(new LoginPane.LoginListener() {
@Override
public void loginDidFail(LoginPane source) {
JOptionPane.showMessageDialog(NavigationPane.this, "You are not unauthroised", "Error", JOptionPane.ERROR_MESSAGE);
}
@Override
public void loginWasSuccessful(LoginPane source) {
navigateTo(NavigationTarget.MAIN);
}
});
mainPane = new MainPane();
add(loginPane, NavigationTarget.LOGIN.name());
add(mainPane, NavigationTarget.MAIN.name());
navigateTo(NavigationTarget.LOGIN);
}
protected void navigateTo(NavigationTarget target) {
cardLayout.show(this, target.name());
}
}
public static class LoginPane extends JPanel {
public static interface LoginListener extends EventListener {
public void loginDidFail(LoginPane source);
public void loginWasSuccessful(LoginPane source);
}
public LoginPane() {
setBorder(new EmptyBorder(10, 10, 10, 10));
setLayout(new GridBagLayout());
JButton btn = new JButton("Login");
btn.addActionListener(new ActionListener() {
private Random rnd = new Random();
@Override
public void actionPerformed(ActionEvent e) {
// Do some logic here
if (rnd.nextBoolean()) {
fireLoginWasSuccessful();
} else {
fireLoginDidFail();
}
}
});
add(btn);
}
public void addLoginListener(LoginListener listener) {
listenerList.add(LoginListener.class, listener);
}
public void removeLoginListener(LoginListener listener) {
listenerList.remove(LoginListener.class, listener);
}
protected void fireLoginDidFail() {
LoginListener[] listeners = listenerList.getListeners(LoginListener.class);
for (LoginListener listener : listeners) {
listener.loginDidFail(this);
}
}
protected void fireLoginWasSuccessful() {
LoginListener[] listeners = listenerList.getListeners(LoginListener.class);
for (LoginListener listener : listeners) {
listener.loginWasSuccessful(this);
}
}
}
public static class MainPane extends JPanel {
public MainPane() {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(10, 10, 10, 10));
add(new JLabel("Welcome"));
}
}
}
JDialog
基于登录工作流程import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.EmptyBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
NavigationPane navigationPane = new NavigationPane();
JFrame frame = new JFrame();
frame.add(navigationPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
if (LoginPane.showLoginDialog(navigationPane)) {
navigationPane.didLogin();
} else {
frame.dispose();
}
}
});
}
public static class NavigationPane extends JPanel {
protected enum NavigationTarget {
SPLASH, MAIN;
}
private SplashPane splashPane;
private MainPane mainPane;
private CardLayout cardLayout;
public NavigationPane() {
cardLayout = new CardLayout();
setLayout(cardLayout);
mainPane = new MainPane();
splashPane = new SplashPane();
add(splashPane, NavigationTarget.SPLASH.name());
add(mainPane, NavigationTarget.MAIN.name());
navigateTo(NavigationTarget.SPLASH);
}
protected void navigateTo(NavigationTarget target) {
cardLayout.show(this, target.name());
}
public void didLogin() {
navigateTo(NavigationTarget.MAIN);
}
}
public static class LoginPane extends JPanel {
private Random rnd = new Random();
private boolean isAuthorised = false;
public LoginPane() {
setBorder(new EmptyBorder(10, 10, 10, 10));
setLayout(new GridBagLayout());
add(new JLabel("User name and password fields go here"));
}
protected void authenticate() {
// Authenticate
isAuthorised = rnd.nextBoolean();
if (!isAuthorised) {
JOptionPane.showMessageDialog(this, "You are not authorised", "Error", JOptionPane.ERROR_MESSAGE);
}
}
// So this should return some kind of "session" or something so
// can identify the user, but for now, we'll just use
// a boolean
public boolean isAuthorised() {
return isAuthorised;
}
public static boolean showLoginDialog(Component parent) {
LoginPane loginPane = new LoginPane();
JPanel panel = new JPanel(new BorderLayout());
JPanel buttonPane = new JPanel(new GridBagLayout());
JButton okayButton = new JButton("Login");
JButton cancelButton = new JButton("Cancel");
buttonPane.add(okayButton);
buttonPane.add(cancelButton);
panel.add(loginPane);
panel.add(buttonPane, BorderLayout.SOUTH);
JDialog dialog = new JDialog(SwingUtilities.windowForComponent(parent));
dialog.add(panel);
okayButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
loginPane.authenticate();
if (loginPane.isAuthorised()) {
dialog.dispose();
}
}
});
cancelButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
dialog.dispose();
}
});
dialog.setModal(true);
dialog.pack();
dialog.setLocationRelativeTo(parent);
dialog.setVisible(true);
return loginPane.isAuthorised();
}
}
public static class SplashPane extends JPanel {
public SplashPane() {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(10, 10, 10, 10));
add(new JLabel("This is a splash panel, put some nice graphics here"));
}
}
public static class MainPane extends JPanel {
public MainPane() {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(10, 10, 10, 10));
add(new JLabel("Welcome"));
}
}
}
您复制了 JFrame,并在 JFrame 内创建了一个 JFrame 字段
f
。
不要使用按钮等静态组件。
public class Frame1 extends JFrame implements ActionListener {
private final JButton login = new JButton("Login");
Frame1() {
setTitle("Login");
setSize(1000, 750);
setLocation(750, 250);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(null);
login.setBounds(250, 350, 150, 30);
add(login);
login.addActionListener(this);
setVisible(true);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == login) {
Frame2.frame2windown();
}
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
Frame1 login1 = new Frame1();
}
}
}
使用 swing/awt 事件队列 (
invokeLater
),因为在此线程上窗口事件将被进一步处理和分派。
和框架2:
public class Frame2 extends JFrame implements ActionListener {
private JButton logout = new JButton("Logout");
private JLabel jb1 = new JLabel("Hello And Welcome");
Frame2() {
setTitle("Logout");
setSize(1000, 750);
setLocation(750, 250);
setLayout(null);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
jb1.setBounds(250, 150, 350, 30);
logout.setBounds(250, 350, 150, 30);
add(logout);
add(jb1);
logout.addActionListener(this);
setVisible(true);
}
public void actionPerformed(ActionEvent a) {
if (a.getSource() == logout) {
setVisible(false); // <--- ALL
}
}
public static void frame2windown() {
Frame2 f2 = new Frame2();
}
}
JFrame.setVisible
做到了这一切。特别是 setVisible(true)
甚至应该在调用构造函数之后完成,所以它总是最后一个。
另一句话,快速深入布局管理器。绝对布局(空)是 PITA。
我通过使用解决了这个问题 setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE) 您希望在不影响其他帧的情况下关闭哪个帧