自从我学习了C ++以来，我不禁想到C ++方面的一些其他编程语言（即Java）中的某些特性。这可能是因为我根本不相信他们100％（我认为相信任何100％是愚蠢的），而关于JFrame的东西只能证实我的担忧。我记得在某个地方读过JFrames请求的内存必须在不再使用时返回给系统，这可以通过JFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);来完成我想知道是否有一个类是JFrame在C ++中，使用delete this;类的close()方法调用System.out.print()来进行处理。
我试过这个，并让类实现WindowListener。然后我在windowClosed()，windowClosing()中添加了一些import java.awt.GridLayout;
import java.awt.HeadlessException;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.WindowListener;
import java.awt.event.WindowEvent;
import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
public class ItemListenerDemo extends JFrame implements WindowListener,ItemListener
{
private JRadioButton buttonA, buttonB;
private ButtonGroup radioButtonGroup;
private JLabel buttonSelectionLabel;
private JPanel buttonPanel;
private GridLayout gridLayout;
public ItemListenerDemo(String title) throws HeadlessException
{
super(title);
//setting up the buttons
buttonA = new JRadioButton("Option A", true);
buttonB = new JRadioButton("Option B", false);
//adding itemListeners
buttonA.addItemListener(this);
buttonB.addItemListener(this);
//adding the buttons to the radioButtonGroup
radioButtonGroup = new ButtonGroup();
radioButtonGroup.add(buttonA);
radioButtonGroup.add(buttonB);
//adding buttons to JPanel
buttonPanel = new JPanel();
buttonPanel.add(buttonA);
buttonPanel.add(buttonB);
//making the buttonSelectionLabel
buttonSelectionLabel = new JLabel("some text");
//setting up the gridLayout
gridLayout = new GridLayout(2,1);
//setting the layout of the demo to the gridLayout
setLayout(gridLayout);
//adding components to demo
add(buttonSelectionLabel);
add(buttonPanel);
//setting up the demo
setSize(200,200);
setVisible(true);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}
/**
* @param args
*/
public static void main(String[] args)
{
ItemListenerDemo demo = new ItemListenerDemo("Item Listener Example");
}
@Override
public void itemStateChanged(ItemEvent e) {
// TODO Auto-generated method stub
buttonSelectionLabel.setText("You selected " +
((JRadioButton)e.getItem()).getText());
}
@Override
public void windowActivated(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowClosed(WindowEvent e) {
// TODO Auto-generated method stub
System.out.println(this.toString() + " was deleted");
}
@Override
public void windowClosing(WindowEvent e) {
// TODO Auto-generated method stub
System.out.println(this.toString() + " was deleted");
}
@Override
public void windowDeactivated(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowDeiconified(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowIconified(WindowEvent e) {
// TODO Auto-generated method stub
}
@Override
public void windowOpened(WindowEvent e) {
// TODO Auto-generated method stub
}
方法，并且在关闭JFrame时没有发生任何问题！
我做了类似的事情：
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}
是的，我最后向你展示了我的所有代码
答案 0 :(得分：1)
您似乎忘记添加窗口侦听器：
addWindowListener(this);