Running JTabbedPanel on for loop in java

Question

Hi I tried to run JTabbedPanel using for loop.. My program is running successfully. But its not creating any Tab file as what i expected. please help me.

public void GenerateGUI() {

    jPanel = new JPanel[3];

    jSplitPane1 = new JSplitPane();
    jTabbedPane1 = new JTabbedPane();

    GroupLayout[] jPanelLayout = new GroupLayout[3];

    for (int i = 0; i <= noOfTerminals; i++) {

        jPanel[i] = new JPanel();

        jPanelLayout[i] = new GroupLayout(jPanel[i]);
        jPanel[i].setLayout(jPanelLayout[i]);

        jPanelLayout[i].setHorizontalGroup(jPanelLayout[i]
                .createParallelGroup(
                        javax.swing.GroupLayout.Alignment.LEADING).addGap(
                        0, 449, Short.MAX_VALUE));
        jPanelLayout[i].setVerticalGroup(jPanelLayout[i]
                .createParallelGroup(
                        javax.swing.GroupLayout.Alignment.LEADING).addGap(
                        0, 250, Short.MAX_VALUE));

        jPanel[i].add(lblOverView);

        jTabbedPane1.addTab("OverView", jPanel[i]);
    }

    setLayout(null);
    add(jTabbedPane1);

    setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
    pack();
    setVisible(true);
    setLocationRelativeTo(null);
}

Answer 1

That happens because you use null LayoutManager. So, remove that line setLayout(null); and all will work, or change that line to not null value, for example:

setLayout(new BorderLayout());.

I recommend you don't use null Layout. Examine LayoutManager tutorial. Try for example BorderLayout or other.

Answer 2

    public GenerateGUI() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 450, 300);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP);
    tabbedPane.setBounds(10, 11, 414, 240);
    contentPane.add(tabbedPane);

    JPanel[] panels = new JPanel[3];

    for (int i = 0; i < 3; i++){
        panels[i] = new JPanel();
        panels[i].setVisible(true);
        tabbedPane.addTab("Tab " + Integer.toString(i), null, panels[i], null);
    }
}

Extend your class with JFrame.