在我的一个程序中,我希望在用户尝试退出应用程序时显示一个Dialog。然后,用户必须选择保存程序的某些状态,而不是保存或取消退出操作。
我写这篇文章是为了首先找到解决方案,然后实现它:
import javax.swing.*;
import java.awt.Dimension;
import java.awt.event.*;
class WL implements WindowListener
{
private boolean statussaved;
private JFrame tframe;
WL (JFrame frame)
{
statussaved = false;
tframe = frame;
}
@Override public void windowActivated (WindowEvent w) { }
@Override public void windowClosed (WindowEvent w) { }
@Override public void windowDeactivated (WindowEvent w) { }
@Override public void windowDeiconified (WindowEvent w) { }
@Override public void windowIconified (WindowEvent w) { }
@Override public void windowOpened (WindowEvent w) { }
@Override public void windowClosing (WindowEvent w)
{
if (statussaved)
{
return;
}
final JDialog diag = new JDialog (tframe, "Save Progress", true);
diag.setPreferredSize (new Dimension (500, 100));
diag.setResizable (false);
diag.setDefaultCloseOperation (JDialog.DISPOSE_ON_CLOSE);
JPanel notifypanel = new JPanel ();
notifypanel.add (new JLabel ("Do you want to save the current status ?"));
JButton yesbutton = new JButton ("Yes");
JButton nobutton = new JButton ("No");
JButton cancelbutton = new JButton ("Cancel");
yesbutton.addActionListener (new ActionListener ()
{
@Override public void actionPerformed (ActionEvent a)
{
//SAVE THE STATUS
System.out.println ("Saving status...");
statussaved = true;
diag.dispose ();
tframe.dispose ();
}
});
nobutton.addActionListener (new ActionListener ()
{
@Override public void actionPerformed (ActionEvent a)
{
//just exit/close the application
diag.dispose ();
tframe.dispose ();
}
});
cancelbutton.addActionListener (new ActionListener ()
{
@Override public void actionPerformed (ActionEvent a)
{
//DON'T EXIT !!!
diag.dispose ();
}
});
notifypanel.add (yesbutton);
notifypanel.add (nobutton);
notifypanel.add (cancelbutton);
diag.setContentPane (notifypanel);
diag.pack ();
diag.setVisible (true);
}
}
public class SaveTest
{
public static void main (String[] args)
{
SwingUtilities.invokeLater (new Runnable ()
{
@Override public void run ()
{
JFrame frame = new JFrame ("Save Test");
frame.setDefaultCloseOperation (JFrame.DISPOSE_ON_CLOSE);
frame.addWindowListener (new WL (frame));
JLabel lab = new JLabel ("just some information");
frame.setPreferredSize (new Dimension (400, 300));
frame.setResizable (false);
frame.add (lab);
frame.pack ();
frame.setVisible (true);
}
});
}
}
它编译并运行而不做任何更改,因此您可以对其进行测试。
“是”和“否”选项按预期工作,但我完全不知道在“取消”按钮的ActionListener
中写什么。我想要的是,当用户点击“取消”按钮时,对话框消失,但主窗口仍然可见(即程序继续运行)。
现在,由于所有这些都是在windowClosing
方法中实现的,因此很明显发送了某种处理信号以销毁JFrame
。这意味着在当前的设计中可能无法做到这一点。我不介意重新组织/重新设计所有这些以使其工作。它只是......我不知道如何。
有什么想法吗?
答案 0 :(得分:9)
替换
mainframe.setDefaultCloseOperation (JFrame.DISPOSE_ON_CLOSE);
带
mainframe.setDefaultCloseOperation (JFrame.DO_NOTHING_ON_CLOSE);
如果用户取消关闭 - 什么都不做。如果同意 - 手动调用dispose()
。
答案 1 :(得分:6)
查看JOptionPane,它可以为您处理大部分内容,例如
JOptionPane.showConfirmDialog(frame, "please choose one",
"information",
OptionPane.YES_NO_CANCEL_OPTION,
JOptionPane.INFORMATION_MESSAGE);
您的DefaultCloseOperation
需要DO_NOTHING_ON_CLOSE
,以便您的对话框可以处理事情 - 否则窗口将在用户取消之前被处理掉。然后根据用户的选择手动关闭窗口或退出应用程序。