将JLabel / ImageIcon放置在另一个JLabel / ImageIcon之上

Question

I am trying to create my own small platformer and the problem I am having is putting the character onto the screen. How I have the background loaded on is by using BufferedImages to put a png onto the screen. I convert the BufferedImages to ImageIcons and add to the screen. Like this:

File f = new File("Path Of File");
BufferedImage d = ImageIO.read(f);
JLabel l = new JLabel(new ImageIcon(d));
c.gridx = tile; // Tile is set to the corresponding position on an int array
c.gridy = line; // ^^ So is line
c.insets = new Insets(0, 0, 0, 0);
panel.add(l, c);

And what I am trying to do, is set the image of the character on top of one of those tiles. Here is an example of what I am trying to get to work:

File f = new File(cPath);
    BufferedImage c1 = ImageIO.read(f);
    JLabel l = new JLabel(new ImageIcon(c1));
    l.setLocation(x, y);
    p2.add(l);`

p2 is a JPanel. The layout was set to null:

p2.setLayout(null);

panel is a JPanel. The layout was to to GridBagLayout when it was created:

JPanel panel = new JPanel(new GridBagLayout());

Both panels were added to the JFrame like so:

frame.getContentPane().add(panel, BorderLayout.NORTH);
frame.getContentPane().add(p2);

So if anyone could let me know how to put the JLabel/ImageIcon on top of another JLabel/ImageIcon, it would be greatly appreciated.

EDIT: If you have any questions about what I am trying to achieve, please let me know.

Answer 1

By default components have a size of (0, 0).

So if you use a null layout you are responsible for setting the size of each label you add to the parent label.

So the basic logic is:

JLabel child = new JLabel( new ImageIcon() );
child.setSize( child.getPreferredSize() );
child.setLocation(...);
JLabel parent = new JLabel( new ImageIcon(...) );
parent.add( child );
frame.add( parent );

Or another option is to use layout managers. For example you can center the child on the parent using:

parent.setLayout( new GridBagLayout() );
parent.add(child, new GridBagConstraints());

Now there is no need to play with the size/location of the child since the layout manager will look after this.