Question

我想在打开另一个之前完全关闭一个JFrame。

考虑代码：

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.net.InetAddress;
import javax.swing.*;
import javax.swing.border.EmptyBorder;


/**
 * 
 * @author X
 *
 */
class ServerConnect extends JFrame implements ActionListener
{
    private static final long serialVersionUID = 1L;
    private JTextField m_serverIP;
    private JTextField m_serverPort; // you can use also JPasswordField
    private JButton m_submitButton;

    // location of the jframe
    private final int m_centerX = 500;
    private final int m_centerY = 300;

    // dimensions of the jframe
    private final int m_sizeX = 1650;
    private final int m_sizeY = 150;


    /**
     * Ctor
     */
    ServerConnect()
    {
        this.setTitle("Sever Side Listener");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        m_serverIP = new JTextField(20);
        m_serverPort = new JTextField(20);

        JPanel gui = new JPanel(new BorderLayout(3,3));
        gui.setBorder(new EmptyBorder(5,5,5,5));
        gui.setSize(m_sizeX , m_sizeY);
        this.setContentPane(gui);

        JPanel labels = new JPanel(new GridLayout(0,1));
        JPanel controls = new JPanel(new GridLayout(0,1));
        gui.add(labels, BorderLayout.WEST);
        gui.add(controls, BorderLayout.CENTER);

        labels.add(new JLabel("Server IP: "));
        controls.add(m_serverIP);
        labels.add(new JLabel("Server Port: "));
        controls.add(m_serverPort);
        m_submitButton = new JButton("Start Listening");
        m_submitButton.addActionListener(this);

        gui.add(m_submitButton, BorderLayout.SOUTH);
        this.setLocation(m_centerX , m_centerY);
        this.setSize(m_sizeX , m_sizeY);
        this.pack();
        this.setVisible(true);
    }

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

    @Override
    public void actionPerformed(ActionEvent event) {

        Object object = event.getSource();
        if (object == this.m_submitButton)
        {
            // grab all values from the connection box 
            // if one of them is missing then display an alert message 

            String ip = this.m_serverIP.getText().trim();
            String port = this.m_serverPort.getText().trim();

            if (ip.length() == 0)
            {
                JOptionPane.showMessageDialog(null, "Please enter IP address !");
                return;
            }

            if (port.length() == 0)
            {
                JOptionPane.showMessageDialog(null, "Please enter Port number!");
                return;
            }

            int s_port = 0;

            try
            {
                // try parse the Port number 
                // throws exception when an incorrect IP address 
                // is entered , and caught in the catch block 
                s_port = Integer.parseInt(port);
            }

            catch(Exception exp)
            {
                JOptionPane.showMessageDialog(null, "Port number is incorrect!");
                return;
            }

            try
            {
                // try parse the IP address 
                // throws exception when an incorrect IP address 
                // is entered , and caught in the catch block 
                InetAddress.getByName(ip);
            }

            catch(Exception exp)
            {
                JOptionPane.showMessageDialog(null, "IP address is incorrect!");
                return;
            }
            this.setVisible(false);
            new ServerGUI(ip , s_port);
        }
    }
}

在用户输入IP号码和端口后的actionPerformed()中，我将窗口设置为false，即：

        this.setVisible(false);      // don't show the current window
        new ServerGUI(ip , s_port);  // open another JFrame

我想完全关闭当前JFrame，而不是将其可见性设置为false。

我该怎么做？

此致

Answer 1

您的问题似乎是，如果您在JFrame上调用close，程序将退出，因为您已将其setDefaultCloseOperation设置为setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);。

选项：

使用不同的defaultCloseOperation，一个不关闭应用程序的，可能是JFrame.DISPOSE_ON_CLOSE。
最初使用JDialog而不是JFrame。这些类型的Windows 无法关闭应用程序。这是JDialog and JOptionPane Tutorial
根本不要交换JFrame，而是使用CardLayout交换视图。 The CardLayout Tutorial link

我自己的偏好是尽可能多地使用CardLayout，以避免让那些通常不喜欢把一堆窗户扔给他的用户烦恼。当我想以模态方式从用户那里获取信息时，我也使用模态JDialogs，即，在用户提供所请求的信息之前应用程序绝对不能向前移动，而非模态对话框为用户呈现程序状态监视信息。我几乎从不在一个应用程序中使用多个JFrame。

修改
顺便说一句，我几乎从不创建扩展JFrame或任何顶级窗口的类，因为我发现它太受限制了。相反，我的大多数GUI类型都面向创建JPanels。这样做的好处是我可以决定何时何地放置JPanel，并且可以随时改变主意。它可以进入JFrame，JDialog，JOptionPane，是一个在CardLayout中交换的卡，......在任何地方。

修改2

例如，这是一个使用您的代码的小程序，略有修改，并将其放入JDialog中：

我的代码：

import java.awt.Dialog.ModalityType; import java.awt.Window; import java.awt.event.ActionEvent; import java.awt.event.KeyEvent; import javax.swing.*; public class MyServerMain extends JPanel { private JTextField serverIp = new JTextField(8); private JTextField serverPort = new JTextField(8); private ServerConnect serverConnect = new ServerConnect(); private JDialog serverConnectDialog = null; public MyServerMain() { serverIp.setFocusable(false); serverPort.setFocusable(false); add(new JLabel("Server IP:")); add(serverIp); add(new JLabel("Server Port:")); add(serverPort); add(new JButton(new SetUpServerAction("Set Up Server", KeyEvent.VK_S))); } private class SetUpServerAction extends AbstractAction { public SetUpServerAction(String name, int keyCode) { super(name); putValue(MNEMONIC_KEY, keyCode); } @Override public void actionPerformed(ActionEvent evt) { if (serverConnectDialog == null) { Window owner = SwingUtilities.getWindowAncestor(MyServerMain.this); serverConnectDialog = new JDialog(owner, "Server Set Up", ModalityType.APPLICATION_MODAL); serverConnectDialog.getContentPane().add(serverConnect); serverConnectDialog.pack(); serverConnectDialog.setLocationRelativeTo(owner); } serverConnectDialog.setVisible(true); // when here, the dialog is no longer visible // so extract information from the serverConnect object serverIp.setText(serverConnect.getServerIp()); serverPort.setText(serverConnect.getServerPort()); } } private static void createAndShowGui() { MyServerMain mainPanel = new MyServerMain(); JFrame frame = new JFrame("My Server Main"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(mainPanel); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGui(); } }); } }

您修改过的代码：

import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.net.InetAddress; import javax.swing.*; import javax.swing.border.EmptyBorder; class ServerConnect extends JPanel implements ActionListener { private static final long serialVersionUID = 1L; private JTextField m_serverIP; private JTextField m_serverPort; // you can use also JPasswordField private JButton m_submitButton; // location of the jframe private final int m_centerX = 500; private final int m_centerY = 300; // dimensions of the jframe private final int m_sizeX = 1650; private final int m_sizeY = 150; ServerConnect() { m_serverIP = new JTextField(20); m_serverPort = new JTextField(20); JPanel gui = new JPanel(new BorderLayout(3, 3)); gui.setBorder(new EmptyBorder(5, 5, 5, 5)); gui.setSize(m_sizeX, m_sizeY); setLayout(new BorderLayout()); // !! add(gui, BorderLayout.CENTER); JPanel labels = new JPanel(new GridLayout(0, 1)); JPanel controls = new JPanel(new GridLayout(0, 1)); gui.add(labels, BorderLayout.WEST); gui.add(controls, BorderLayout.CENTER); labels.add(new JLabel("Server IP: ")); controls.add(m_serverIP); labels.add(new JLabel("Server Port: ")); controls.add(m_serverPort); m_submitButton = new JButton("Start Listening"); m_submitButton.addActionListener(this); gui.add(m_submitButton, BorderLayout.SOUTH); this.setLocation(m_centerX, m_centerY); this.setSize(m_sizeX, m_sizeY); // !! this.pack(); // !! this.setVisible(true); } public static void main(String[] args) { new ServerConnect(); } @Override public void actionPerformed(ActionEvent event) { Object object = event.getSource(); if (object == this.m_submitButton) { // grab all values from the connection box // if one of them is missing then display an alert message String ip = this.m_serverIP.getText().trim(); String port = this.m_serverPort.getText().trim(); if (ip.length() == 0) { JOptionPane.showMessageDialog(null, "Please enter IP address !"); return; } if (port.length() == 0) { JOptionPane.showMessageDialog(null, "Please enter Port number!"); return; } int s_port = 0; try { // try parse the Port number // throws exception when an incorrect IP address // is entered , and caught in the catch block s_port = Integer.parseInt(port); } catch (Exception exp) { JOptionPane.showMessageDialog(null, "Port number is incorrect!"); return; } try { // try parse the IP address // throws exception when an incorrect IP address // is entered , and caught in the catch block InetAddress.getByName(ip); } catch (Exception exp) { JOptionPane.showMessageDialog(null, "IP address is incorrect!"); return; } // !! this.setVisible(false); // !! new ServerGUI(ip , s_port); // !! Window ownerWindow = SwingUtilities.getWindowAncestor(this); ownerWindow.dispose(); } } // !! public String getServerIp() { return m_serverIP.getText(); } // !! public String getServerPort() { return m_serverPort.getText(); } }

Answer 2

希望这个another_Frame frm = new another_Frame(); frm.setVisible(true); this.dispose();// this represent the fram to close

在打开另一个JFrame之前关闭一个JFrame

2 个答案: