'Blocking' calls like dialog forms in .NET

Hey,

I need to show a 'level select' window in my game, and it's only purpose is to select a level from a list of available levels, and return the filename of that level.

In .NET, I would have made a dialog form, display it with ShowDialog such that the calling code would halt until the form returned, and then used a property to communicate which level was selected. For example, in C# this could look like

csharp Code:

string levelPath = String.Empty;
frmLevelSelect f = new frmLevelSelect();
if (f.ShowDialog() == DialogResult.OK)
{
    levelPath = f.SelectedLevel;
}
 
if (levelPath != String.Empty)
{
    // ... load level
}

The ShowDialog call waits until the DialogResult has been set in the frmLevelSelect form, so we can be sure that, if the user pressed OK, he has actually selected a level.

If I try the same in java, replacing ShowDialog with setVisible(true), then it does not block, but it returns immediately, and obviously the user has had no chance to select a level yet.



How can I do this? Or is there no built-in mechanism for this and should I use threads?

Use the JDialog. it works the same. Just make sure this JDialog is a modal

Code:

---

import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class Test extends JFrame
{
        private static final long serialVersionUID = 1L;
        private final JButton button;

        public Test()
        {
                super("Test");
                button = new JButton("Click");
                button.addActionListener(new ActionListener()
                {
                        public void actionPerformed(final ActionEvent e)
                        {
                                new TestDialog(Test.this);
                                JOptionPane.showMessageDialog(Test.this, "Hello World!");
                        }
                });
                this.add(button);
                this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                pack();
        }

        public static void main(final String[] args)
        {
                new Test().setVisible(true);
        }
}

class TestDialog extends JDialog
{
        private static final long serialVersionUID = 1L;

        public TestDialog(final Frame owner)
        {
                super(owner, true);
                this.add(new JTextField("Hello World!"));
                setLocationRelativeTo(owner);
                pack();
                setVisible(true);
        }
}

---

Cool, didn't know that. Let me try it out.