BorderLayout in Swing Java not working correctly

Question

I have created a password generator in Java which works perfectly. My functionality is working (after a lot of tears, sweat and blood :) ), but the only problem that remains is the layout of my GUI.

My approach was the following:

• 1 pane (Top/North) for the title
• 1 pane in the center for the form
• 1 pane (bottom/south) for the buttons and textfield

This is the result

as you can see this is not how I wanted it. But if I look at my code, it should be placed nicely from top to bottom.

Where did it go wrong?

My code:

The constructor (extends from JFrame)

public PasswordGenerator(){
    this.setContentPane(ContentPane());
    this.setSize(500,270);
    this.setResizable(true);
    this.setVisible(true);
}

The panes:

private JPanel ContentPane()
{
    JPanel ContentPane = new JPanel();
    ContentPane.add(getTopPane(), BorderLayout.NORTH);
    ContentPane.add(getCenterPane(),BorderLayout.CENTER);
    ContentPane.add(getSouthPane(),BorderLayout.EAST);
    return ContentPane;
}

private JPanel getTopPane(){
    JPanel TopPane = new JPanel();
    JLabel intro = new JLabel("Password generator V1.0");
    intro.setFont(new Font("TimesRoman",Font.BOLD,20));
    TopPane.setLayout(new GridLayout(1,1));
    TopPane.add(intro);
    return TopPane;
}

private JPanel getCenterPane(){
    JPanel CenterPane = new JPanel();

    CenterPane.add(aantalChars);
    CenterPane.setLayout(new GridLayout(6,3));
    //8,2
    hidden.setVisible(false);
    hiddenL.setVisible(false);
    CenterPane.add(aantalCharsLabel);
    CenterPane.add(hidden);
    CenterPane.add(hidden);
    CenterPane.add(hiddenL);
    CenterPane.add(lowerCase);
    CenterPane.add(lowerCaseLabel);
    CenterPane.add(upperCase);
    CenterPane.add(upperCaseLabel);
    CenterPane.add(numberCase);
    CenterPane.add(numberCaseLabel);
    CenterPane.add(symbolCase);
    CenterPane.add(symbolCaseLabel);


    return CenterPane;
}

Answer 1

You forgot to set the BorderLayout as LayoutManager on your ContentPane . Just using the right constraints is not enough. You can use ContentPane.setLayoutManager() for this, or you can give the LayoutManager directly in the constructor of JPanel .

Answer 2

The default layout manager for JPanel is FlowLayout manager. To use BorederLayout you need to set it specifically :

private JPanel ContentPane()
        {
            JPanel ContentPane = new JPanel();
            //////////////////////////////////////////////
            ContentPane.setLayout(new BorderLayout());
            ////////////////////////////////////////////
            ContentPane.add(getTopPane(), BorderLayout.NORTH);
            ContentPane.add(getCenterPane(),BorderLayout.CENTER);
            ContentPane.add(getSouthPane(),BorderLayout.SOUTH);
            return ContentPane;
        }