我用一个ok按钮创建了一个框架。如果单击此按钮，框架窗口应关闭并销毁框架窗口的内存，之后它将打开另一个框架，同时单击该确定按钮。
以下代码是否正确？
public class GlobalVariableClass1 extends javax.swing.JFrame {
public static String GVar;
public GlobalVariableClass1() {
initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel2 = new javax.swing.JPanel();
Cmd01 = new javax.swing.JButton();
jPanel1 = new javax.swing.JPanel();
Txt01 = new javax.swing.JTextField();
Lbl02 = new javax.swing.JLabel();
Lbl01 = new javax.swing.JLabel();
Lbl03 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
addWindowListener(new java.awt.event.WindowAdapter() {
public void windowClosing(java.awt.event.WindowEvent evt) {
formWindowClosing(evt);
}
});
getContentPane().setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jPanel2.setBorder(javax.swing.BorderFactory.createTitledBorder(javax.swing.BorderFactory.createMatteBorder(1, 1, 1, 1, java.awt.Color.darkGray), "Commands", javax.swing.border.TitledBorder.DEFAULT_JUSTIFICATION, javax.swing.border.TitledBorder.DEFAULT_POSITION, new java.awt.Font("Arial", 0, 12))); // NOI18N
jPanel2.setFont(new java.awt.Font("Arial", 0, 12)); // NOI18N
Cmd01.setText("Class B");
Cmd01.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
Cmd01ActionPerformed(evt);
}
});
javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGap(20, 20, 20)
.addComponent(Cmd01)
.addContainerGap(33, Short.MAX_VALUE))
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addContainerGap()
.addComponent(Cmd01, javax.swing.GroupLayout.DEFAULT_SIZE, 33, Short.MAX_VALUE)
.addContainerGap())
);
getContentPane().add(jPanel2, new org.netbeans.lib.awtextra.AbsoluteConstraints(250, 10, 130, 80));
jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder(javax.swing.BorderFactory.createMatteBorder(1, 1, 1, 1, java.awt.Color.darkGray), "GlobalValue", javax.swing.border.TitledBorder.DEFAULT_JUSTIFICATION, javax.swing.border.TitledBorder.DEFAULT_POSITION, new java.awt.Font("Arial", 0, 12))); // NOI18N
Txt01.setFont(new java.awt.Font("Arial", 0, 12)); // NOI18N
Lbl01.setText("Value Entered in C");
Lbl03.setText("Enter Value");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addComponent(Lbl03, javax.swing.GroupLayout.DEFAULT_SIZE, 74, Short.MAX_VALUE)
.addGap(43, 43, 43)
.addComponent(Txt01, javax.swing.GroupLayout.PREFERRED_SIZE, 94, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(29, 29, 29))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addComponent(Lbl01, javax.swing.GroupLayout.DEFAULT_SIZE, 121, Short.MAX_VALUE)
.addGap(18, 18, 18)
.addComponent(Lbl02, javax.swing.GroupLayout.PREFERRED_SIZE, 91, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap())))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addComponent(Lbl02, javax.swing.GroupLayout.DEFAULT_SIZE, 25, Short.MAX_VALUE))
.addComponent(Lbl01, javax.swing.GroupLayout.DEFAULT_SIZE, 36, Short.MAX_VALUE))
.addGap(34, 34, 34)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(Lbl03, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(Txt01, javax.swing.GroupLayout.PREFERRED_SIZE, 29, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(36, 36, 36))
);
getContentPane().add(jPanel1, new org.netbeans.lib.awtextra.AbsoluteConstraints(20, 120, 260, 160));
pack();
}// </editor-fold>
// ** this is the way i used, is it correct:**
private void Cmd01ActionPerformed(java.awt.event.ActionEvent evt) {
GVar=Txt01.getText();
dispose();
new GlobalVariableClass2().setVisible(true);
}
private void formWindowClosing(java.awt.event.WindowEvent evt) {
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new GlobalVariableClass1().setVisible(true);
}
});
}
答案 0 :(得分：1)
如果您从未将GlobalVariableClass1的实例分配给其他类中的任何变量或字段，dispose()将执行您想要的操作。例如：
new GlobalVariableClass1().setVisible(true);
将创建一个临时变量来保存new的结果，然后使用临时变量来调用setVisible()。由于变量只是暂时的，因此只要Java看到;（可以这么说）就会忘记它。
这将切断与new创建的实例的所有联系，GC将能够收集它（=释放内存）。
如果你仍然感到困惑，那么GC就是这样的：
当然，2012年GC的使用寿命要复杂得多，但就简单来说，这就是GC始终如何运作。