按钮点击时如何关闭框架 [英] how to close a frame when button clicks
问题描述
我是Java Swing的新手。我正在创建一个包含一些组件的框架。
I am new to Java Swing. I am creating a frame with some components.
我必须关闭框架并在单击按钮时打开另一个框架。我曾尝试 setVisible（false）但它只隐藏了框架，而没有关闭它。当我使用 System.exit（0）时，它会关闭所有帧。
I have to close the frame and open another frame when the button is clicked. I had tried setVisible(false) but it only hides the frame, not closing it. When I use System.exit(0), it closed all the frames.
我曾尝试过其他方式，即将所有组件添加到面板，并首先添加面板。当帧必须关闭时，我只需删除actionListener中的那些组件，并为相应的下一个进程添加其他组件。
I had tried in another way, i.e. add all the components to panel, and add the panel at first. When the frame has to close I just remove those components in actionListener and add the other components for the corresponding next process.
我的整个代码如下：
package JavaApp;
import java.awt.Component;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.security.NoSuchAlgorithmException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.IllegalBlockSizeException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class Login extends JFrame {
public static JLabel labelUser;
public static JLabel labelPass;
public static JTextField textFieldUser;
public static JPasswordField passwordField;
public static JButton clear;
public static JButton buttonLogin;
public static JButton ChangePassword;
public static JButton MasterKey;
public static JButton AppKey;
public static JPanel panelGnereate;
public static JPanel panelLogin;
public static JFrame frame;
public static JLabel UserName;
public static JTextField UserTxt;
public static JButton GenerateKey;
public static JPanel panelMaster;
private static void designUI() {
frame = new JFrame("Instalation");
frame.setLayout(new GridLayout(2, 1));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panelLogin = new JPanel();
panelLogin.setLayout(null);
labelUser = new JLabel("Enter UserName");
textFieldUser = new JTextField(10);
labelPass = new JLabel("Enter Password");
passwordField = new JPasswordField(10);
buttonLogin = new JButton("Login");
clear = new JButton("Cancel");
panelLogin.add(buttonLogin);
panelLogin.add(clear);
panelLogin.add(labelUser);
panelLogin.add(textFieldUser);
panelLogin.add(labelPass);
panelLogin.add(passwordField);
textFieldUser.setBounds(200, 120, 100, 20);
labelUser.setBounds(50, 120, 120, 20);
labelPass.setBounds(50, 150, 120, 20);
passwordField.setBounds(200, 150, 100, 20);
buttonLogin.setBounds(70, 180, 100, 20);
clear.setBounds(200, 180, 100, 20);
buttonLogin.addActionListener(actionEvent);
clear.addActionListener(actionEvent);
frame.add(panelLogin);
//Login frame ends...
//Gnereate frame starts here..
panelGnereate = new JPanel();
panelGnereate.setLayout(null);
ChangePassword = new JButton("Change Password");
MasterKey = new JButton("Create Master Key");
AppKey = new JButton("Create Application key");
panelGnereate.add(ChangePassword);
panelGnereate.add(MasterKey);
panelGnereate.add(AppKey);
ChangePassword.setBounds(150, 100, 200, 25);
MasterKey.setBounds(150, 150, 200, 25);
AppKey.setBounds(150, 200, 200, 25);
ChangePassword.addActionListener(actionEvent);
MasterKey.addActionListener(actionEvent);
AppKey.addActionListener(actionEvent);
//Gnerate Frame ends here..
//MasterKey Generate Starts Here..
panelMaster = new JPanel();
panelMaster.setLayout(null);
UserName = new JLabel("Text");
UserTxt = new JTextField(20);
GenerateKey = new JButton("Generate Key");
panelMaster.add(UserName);
panelMaster.add(UserTxt);
panelMaster.add(GenerateKey);
UserName.setBounds(150, 150, 50, 25);
UserTxt.setBounds(220, 150, 100, 25);
GenerateKey.setBounds(180, 180, 150, 25);
GenerateKey.addActionListener(actionEvent);
frame.setSize(500, 500);
frame.setVisible(true);
}
public static void main(String args[]) {
designUI();
}
private static ActionListener actionEvent = new ActionListener() {
public void actionPerformed(ActionEvent e) {
String action = e.getActionCommand();
if ("Login".equals(action)) {
System.out.println("Login action" + e.getActionCommand());
if ("".equals(textFieldUser.getText()) || "".equals(passwordField.getText())) {
JOptionPane.showMessageDialog(null,
"Enter Both UserName and Password");
} else if ("admin".equals(textFieldUser.getText()) && "admin".equals(passwordField.getText())) {
System.out.println("login value" + textFieldUser.getText() + " " + passwordField.getText());
frame.remove(panelLogin);
frame.add(panelGnereate);
frame.setVisible(true);
} else {
JOptionPane.showMessageDialog(null,
"Wrong Password");
}
} else if ("Cancel".equals(action)) {
System.out.println(e.getActionCommand());
System.exit(0);
} else if ("Change Password".equals(action)) {
} else if ("Create Master Key".equals(action)) {
frame.remove(panelGnereate);
frame.add(panelMaster);
frame.setVisible(true);
} else if ("Create Application key".equals(action)) {
System.out.println("Message " + UserTxt.getText());
frame.setVisible(false);
}else if("Generate Key".equals(action))
{
try {
new GenerateTxt(UserTxt.getText());
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
} catch (IllegalBlockSizeException ex) {
Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
}
frame.remove(panelMaster);
frame.add(panelGnereate);
frame.setVisible(true);
}
}
;
};
}
在整个过程中它不起作用。单击genearteKey后单击主键时显示相关文本框，显示相同的面板而不是上一个面板。但当我在那里移动鼠标时，它显示了两个面板的组件。
It's not working for throughout the process. When I click the master key it showing relevant textbox after clicking genearteKey it showing same panel not the previous one. But when I am moving the mouse over there it is showing the components of the both panels.
推荐答案
查看你的代码，你可能需要这样的东西：
looking at your code, you'll probably need something like this:
if(frame == null)
frame = new JFrame();
else {
//remove the previous JFrame
frame.setVisible(false);
frame.dispose();
//create a new one
frame = new JFrame();
}
你必须把它放在actionperformed方法中，这样框架可以被删除..
顺便说一句，根据良好的编程习惯，将你的类变量从公共变为私有是一个gd想法。
you'll have to put this inside the actionperformed method so that the frame can be removed.. btw, it would be a gd idea to change your class variables from public to private, in accordance with good programming practice..
编辑：回答闪烁问题。
您从事件线程外部访问swing组件。摆动小部件通常不是线程安全的。因此，你需要修改你的主要方法：
EDIT: To answer the "flickering" problem. you're accessing the swing component from outside the event thread. swing widgets arent generally thread safe. as such, u need to modify your main method:
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
designUI();
}
});
}
另请参阅 Swing组件在更新时闪烁以进行进一步查询。
also, refer to Swing component flickering when updated a lot for further queries.
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