GridLayout and number of rows and columns

Question

Does GridLayout ever not honor the number of rows and columns you've specified if you don't fill it completely?

I'm creating a GridLayout with 3 rows and 4 columns. However, I'm only adding 9 components. It ends up showing me these 9 components in a 3x3 grid, rather than a 3x4 grid (with only 1 component on the third row (and two blanks)).

Answer 1

rather than a 3x4 grid (with only 1 component on the third row (and two blanks)).

Then you should be creating your GridLayout using:

setLayout(new GridLayout(0,4)); 

It tell the layout that you don't know how many rows you have, but you want 4 columns. So the columns will be filled up before moving to the next row.

No need for empty components.

Answer 2

Just fill empty cells with empty items (like a JLabel), eg:

class MyFrame extends JFrame
{
    MyFrame()
    {
        setLayout(new GridLayout(3,4));

        for (int i = 0; i < 9; ++i)
            this.getContentPane().add(new JLabel(""+i));
        for (int i = 0; i < 3; ++i)
            getContentPane().add(new JLabel());

        pack();
        setVisible(true);
    }
}

This layouts them as

0 1 2 3
4 5 6 7
9