Question

INTRO:
I created a java application using JFrame. I have a JMenuBar at the top and under that I’d like to display rows of text.

PURPOSE:
When I have 50 rows and only 20 are displayable at once, I’d like to be able to scroll down and back up again.

PROBLEM:
Of course, my theory doesn’t wanna work as it should. My problem is that I don’t know how to add a vertical scroll properly.

QUESTION:
How should I change this code to reach my goal?

public void display(){

    Container content = this.window.getContentPane();
    content.setLayout(new BorderLayout());
    Border border = LineBorder.createGrayLineBorder();

    //this is just a sample 
    for(int i = 0;i<50;i++){
        JLabel lab = new JLabel("lonyaladek");
        lab.setSize(570, 20);
        lab.setBorder(border);
        lab.setLocation(10, 20+(i*25));
        content.add(lab);
    }

    //scroll
    JScrollBar sb = new JScrollBar(JScrollBar.VERTICAL, 0, 0, 0, 0);
    content.add(sb);
}

Answer 1

First you need to start with a layout manager that allows you to add multiple components to the container. Maybe a GridLayout is the best place to start.

Then you add this container to the scrollPane and then you add the scrollpane to the window.

So the basic code would be:

JPanel panel = new JPanel( new GridLayout(0, 1) );
panel.add(...);
panel.add(...);
JScrollPane scrollPane = new JScrollPane( panel );
window.add(scrollPane, BorderLayout.CENTER);

I suggest you read the section from the Swing tutorial on How to Use Scroll Panes for more info.