Second JFrame doesn't show from first JFrame

Question

This is a simple JFrame application. It basically creates a new Frame on basis of the user choice. The first frame starts but the new one doesn't show up! It show the errors- ie1 cannot be resolved & ie2 cannot be resolved . I want to see the new Frame .

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

class Test2 {
    public static void main(String[] args) {
        JFrame jf = new JFrame("Java test");
        Container c = jf.getContentPane();
        jf.setBounds(450, 180, 450, 450);
        jf.setVisible(true);
        jf.setDefaultCloseOperation(jf.EXIT_ON_CLOSE);
        JPanel jp = new JPanel();
        c.add(jp);
        JLabel jl = new JLabel("This is a text in a label",SwingConstants.CENTER);
        jp.add(jl);
        JComboBox jcb1 = new JComboBox();
        jp.add(jcb1);
        jcb1.addItemListener(new ItemListener() {
            public void itemStateChanged(final ItemEvent ie1) {
                ie1.getItem();
            }
        });
        jcb1.addItem("       Select the Size       ");
        jcb1.addItem("100 x 100");
        jcb1.addItem("200 x 200");
        jcb1.addItem("300 x 300");
        jcb1.addItem("400 x 400");
        jcb1.addItem("500 x 500");
        jcb1.addItem("600 x 600");
        JComboBox jcb2 = new JComboBox();
        jp.add(jcb2);
        jcb2.addItemListener(new ItemListener() {
            public void itemStateChanged(final ItemEvent ie2) {
                ie2.getItem();
            }
        });
        jcb2.addItem("       Select the Colour     ");
        jcb2.addItem("Blue");
        jcb2.addItem("Red");
        jcb2.addItem("Black");
        jcb2.addItem("White");
        jcb2.addItem("Yellow");
        jcb2.addItem("Green");
        JButton jb = new JButton("Create a new Frame");
        jp.add(jb);
        jb.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                final JFrame jf1 = new JFrame("New Frame");
                Container c = jf1.getContentPane();
                jf1.setVisible(true);
                jf1.setDefaultCloseOperation(jf1.EXIT_ON_CLOSE);
                // The Size of the frame
                if (ie1.getItem().equals("       Select the Size       ")) {
                    JOptionPane.showMessageDialog(null, "Please select the size of the Frame");
                }
                if (ie1.getItem().equals("100 x 100"))
                    ;
                {
                    jf1.setBounds(450, 180, 100, 100);
                }
                if (ie1.getItem().equals("200 x 200"))
                    ;
                {
                    jf1.setBounds(450, 180, 200, 200);
                }
                if (ie1.getItem().equals("300 x 300"))
                    ;
                {
                    jf1.setBounds(450, 180, 300, 300);
                }
                if (ie1.getItem().equals("400 x 400"))
                    ;
                {
                    jf1.setBounds(450, 180, 400, 400);
                }
                if (ie1.getItem().equals("500 x 500"))
                    ;
                {
                    jf1.setBounds(450, 180, 500, 500);
                }
                if (ie1.getItem().equals("600 x 600"))
                    ;
                {
                    jf1.setBounds(450, 180, 600, 600);
                }
                // The size of the Frame ends

                // The colour of the frame
                if (ie2.getItem().equals("       Select the Colour     ")) {
                    JOptionPane.showMessageDialog(null, "Please select the colour of the Frame");
                }
                final JPanel jp1 = new JPanel();
                c.add(jp1);
                if (ie2.getItem().equals("Blue")) {
                    jp1.setBackground(Color.blue);
                }
                if (ie2.getItem().equals("Red")) {
                    jp1.setBackground(Color.red);
                }
                if (ie2.getItem().equals("Black")) {
                    jp1.setBackground(Color.black);
                }
                if (ie2.getItem().equals("White")) {
                    jp1.setBackground(Color.white);
                }
                if (ie2.getItem().equals("Yellow")) {
                    jp1.setBackground(Color.yellow);
                }
                if (ie2.getItem().equals("Green")) {
                    jp1.setBackground(Color.green);
                }
                // the colour of the frame ends
            }
        });

    }
}

Answer 1

You are not instantiating, nor initializing the ie1 and ie2 variables anywhere. I can see these represent ItemEvent references, but their scope is limited to the ItemListener 'changed' method.

If you are using Eclipse, it should provide you with a quick fix. But if I were you, I would start reading on Java for Beginners first, and after that move onto the AWT/Swing and SWT/JFace stuff.

Try starting with more basic stuff. It occurs to me that the code above is a bit overwhelming for you. Good luck lil programmer.

Answer 2

Several things: You don't need ItemListeners to get the selected value of the combo boxes, instead just do

Object ie1 = jcb1.getSelectedItem();
Object ie2 = jcb2.getSelectedItem();

right above

if(ie1.equals("       Select the Size       "))
{
    JOptionPane.showMessageDialog(null,"Please select the size of the Frame");
}

And since you're using an anonymous inner class, you'll need to make sure jcb1 and jcb2 are declared final , like so:

final JComboBox jcb1 = new JComboBox();

Also, change ie1.getItem().equals(...) to just ie1.equals(...) , and do the same for ie2 .

On another note, don't put semicolons after if statements.

Right:

if(ie1.equals("100 x 100")) 
{
    ...
}

Wrong:

if(ie1.equals("100 x 100"));
{                        //^
    ...
}

So remove the semicolons that you have after those if statements.

With all that said, I would definitely recommend going with GGrec's advice, and start reading some Java tutorials .