CODEWITHSUNDEEP
javaswing
Karan Nagpal
Karan Nagpal

Reputation: 25

Java - setVisible(true)

I made a simple JDialog which contains a label and a button, its basically an equivalent of information dialog. So in the dialog, there is a method display() in which I called setVisible(true) five times.

From my knowledge, when this display method is called it should only display the dialog once but it actually created 5 dialogs, Why did it create 5 dialogs?

Edit1: My problem is more similar to this :

import java.awt.event.*;import java.awt.*;import javax.swing.*;
class Demo implements ActionListener
{
JFrame f;
JButton b;  
DisplayDialog dialog;
public Demo() 
{
    f = new JFrame();
    f.setSize(200,200);

    b = new JButton("Click me");

    f.add(b);
    dialog = new DisplayDialog();

    b.addActionListener(this);
    f.setVisible(true);
}

public void actionPerformed(ActionEvent e)
{
    Object o = e.getSource();

    if(o==b)
    {
        dialog.display("Hello");
        dialog.display("Hello");
        dialog.display("Hello");
        dialog.display("Hello");
        dialog.display("Hello5");
    }
}

public static void main(String args[])
{
    Demo d = new Demo();
}

class DisplayDialog implements ActionListener
{
        JDialog dg;
        JLabel l;
        JButton b;
        Font myfont;

        public DisplayDialog()
        {
            dg = new JDialog(f,"Alert!",true);
            dg.setSize(300,150);
            l = new JLabel("Message");
            b = new JButton("OK");

            myfont = new Font("Serif",Font.BOLD,12);
            l.setFont(myfont);

            dg.add(l);
            dg.add(b,"South");

            dg.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);

            b.addActionListener(this);
        }

        public void actionPerformed(ActionEvent e)
        {
            Object o = e.getSource();
            if(o==b)
            {
                dg.setVisible(false);
            }
        }

        public void display(String str)
        {
            l.setText(str);
            dg.setVisible(true);

        }
  } 
}

Edit2 : Now a situation like this is occurring in my program and rather than displaying the dialog 5 times, I want it to display the last one, what can i do to achieve this?

Upvotes: 2

Views: 24673

Answers (3)

Antoniossss
Antoniossss

Reputation: 32507

As to your edit: What is your problem then?

Change

if (o == b) {
    dialog.display("Hello");
    dialog.display("Hello");
    dialog.display("Hello");
    dialog.display("Hello");
    dialog.display("Hello5");
}

to

    if (o == b) {
        dialog.display("Hello");
    }

Upvotes: 0

Code-Apprentice
Code-Apprentice

Reputation: 83527

You only create one dialog instance with

dg = new JDialog(f,"Alert!",true);

Then you display this same dialog five times with the multiple calls to setVisible(true).

Upvotes: 0

Antoniossss
Antoniossss

Reputation: 32507

Ok so basicly it is not showing 5 times at once only it is shown 5 times in a row.

JDialog.setVisible(true) is a blocking operation and blocks until dialog is closed.

So one dialog pops up and app blocks on setVisible(true) when you close it, another serVisible(true) is invoked and so on.

Upvotes: 4

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