我制作了一个JFrame表单，其中包含很少的按钮和文本字段。
在小窗户上跑步时看起来很完美。但是当我最大化它时，所有按钮和文本字段都会分散并且不会居中。
即使窗口最大化，框架是否有任何方式看起来居中？
package studentsmarks;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.swing.JOptionPane;
public class LoginCheck extends javax.swing.JFrame {
/**
* Creates new form LoginCheck
*/
public LoginCheck() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
username = new javax.swing.JTextField();
password = new javax.swing.JPasswordField();
signin = new javax.swing.JButton();
jButton1 = new javax.swing.JButton();
jLabel3 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Username");
jLabel2.setText("Password");
signin.setText("Log In");
signin.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
signinActionPerformed(evt);
}
});
jButton1.setText("Sign Up");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jLabel3.setFont(new java.awt.Font("Times New Roman", 1, 14)); // NOI18N
jLabel3.setText("New User?");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(65, 65, 65)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 95, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 80, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(signin)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(password, javax.swing.GroupLayout.DEFAULT_SIZE, 95, Short.MAX_VALUE)
.addComponent(username))))
.addGroup(layout.createSequentialGroup()
.addGap(193, 193, 193)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jButton1)
.addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 89, javax.swing.GroupLayout.PREFERRED_SIZE))))
.addContainerGap(226, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(71, 71, 71)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(username, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(41, 41, 41)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(password, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(32, 32, 32)
.addComponent(signin)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 62, Short.MAX_VALUE)
.addComponent(jLabel3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton1)
.addContainerGap())
);
setSize(new java.awt.Dimension(524, 365));
setLocationRelativeTo(null);
}// </editor-fold>
private void signinActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
Connection conn = null;
try{
//CLass.forName
conn = DriverManager.getConnection("jdbc:mysql://localhost/autouser","root","");
String sql = "select * from test where username = ? and password = ?";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, username.getText());
pstmt.setString(2, password.getText());
ResultSet rs = pstmt.executeQuery();
if(rs.next()){
JOptionPane.showMessageDialog(null,"Logged In Successfully");
String sql1 ="INSERT INTO login(username,password) VALUES ('"+username.getText()+"','"+password.getText()+"')";
pstmt = conn.prepareStatement(sql1);
int r1 = pstmt.executeUpdate(sql1);
//String sub = textSub.getText();
new SubjectDB().setVisible(true);
this.setVisible(false);
}
else{
JOptionPane.showMessageDialog(null,"username and password not correct");
username.setText("");
password.setText("");
}
conn.close();
}
catch(Exception e){
JOptionPane.showMessageDialog(null,e);
}
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
new signup().setVisible(true);
this.setVisible(false);
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(LoginCheck.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(LoginCheck.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(LoginCheck.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(LoginCheck.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new LoginCheck().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JPasswordField password;
private javax.swing.JButton signin;
private javax.swing.JTextField username;
// End of variables declaration
}