看来今晚将是我完成对 Swing 精神错乱的重新洗礼的夜晚。我确信我的问题是一个常见的、简单的问题，但我似乎找不到合适的答案。
继续我在另一个问题中的早期设计，我现在尝试从我的 MainForm 类（也是另一个 JFrame）中调用一个（NetBeans 设计的）JFrame 类，称为 ExamForm，尽管我尝试过，但它并没有表现出来。我将 setVisible() 设置为 true，并使用 MinimumSize 调用了 validate() & pack()，但它仍然只存在于阴间。
这是我在 MainForm 中的事件代码：
private void MenuItem_NewMouseClicked(java.awt.event.MouseEvent evt) {
// TODO add your handling code here:
ExamForm newForm = new ExamForm();
newForm.setMinimumSize(new Dimension(200, 200));
newForm.pack();
newForm.setVisible(true);
newForm.validate();
}
和 ExamForm 类本身：
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package bakarangerx;
/**
*
* @author Ryan
*/
public class ExamForm extends javax.swing.JFrame {
/**
* Creates new form Exam
*/
public ExamForm() {
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() {
Button_OK = new javax.swing.JButton();
Button_Cancel = new javax.swing.JButton();
jLabel1 = new javax.swing.JLabel();
TextField_Filename = new javax.swing.JTextField();
jLabel2 = new javax.swing.JLabel();
ComboBox_Encoding = new javax.swing.JComboBox();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
Button_OK.setText("OK");
Button_OK.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
Button_OKMouseClicked(evt);
}
});
Button_Cancel.setText("Cancel");
Button_Cancel.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
Button_CancelMouseClicked(evt);
}
});
jLabel1.setText("Filename");
jLabel2.setText("Encoding");
ComboBox_Encoding.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(Button_OK, javax.swing.GroupLayout.PREFERRED_SIZE, 93, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(Button_Cancel, javax.swing.GroupLayout.PREFERRED_SIZE, 95, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(379, 379, 379))
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 56, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(TextField_Filename, javax.swing.GroupLayout.PREFERRED_SIZE, 400, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(406, 406, 406))
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 56, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(ComboBox_Encoding, javax.swing.GroupLayout.PREFERRED_SIZE, 183, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(633, 633, 633))))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(TextField_Filename, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 22, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 23, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(ComboBox_Encoding, javax.swing.GroupLayout.PREFERRED_SIZE, 28, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(379, 379, 379)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(Button_Cancel)
.addComponent(Button_OK))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void Button_OKMouseClicked(java.awt.event.MouseEvent evt) {
// TODO add your handling code here:
}
private void Button_CancelMouseClicked(java.awt.event.MouseEvent evt) {
this.setVisible(false);
this.dispose();
}
/**
* @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(ExamForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(ExamForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(ExamForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(ExamForm.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 ExamForm().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton Button_Cancel;
private javax.swing.JButton Button_OK;
private javax.swing.JComboBox ComboBox_Encoding;
private javax.swing.JTextField TextField_Filename;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
// End of variables declaration
}
也许你们中的一个人可以善良，帮助我发现我错过了什么？