updating a gameBoard (JPanel filled with JLabels)

[Bloitz]

Hello again,

My GUI is finished and working (ignoring some minor flaws) but my displayBoard method seems to be extremely inefficient. I made this on my desktop PC and I didn't really notice how CPU or memory intensive it was until our french presentation today. A colleague showed the game on his laptop (which wasn't rubbish or old at all and should definitely be able to cope with a 'game' like this) and it 'lagged' terribly. It took around 1-2 secs to see the player change position.

TL;DR:
The method displayBoard() is called whenever a change occurs to the gameboard (a player moves or an opponent is defeated, opponents don't move and everything else remains the same). The only way I got this to work is by removing all the components (removeAll() ) and readding them with a double for-loop.

This is the inner class I made for the BoardPanel:

private class BoardPanel extends JPanel {

		private LblFinish lblFinish;
		private LblEmpty lblEmpty;
		private LblObst lblObst;
		private LblPlayer lblPlayer;
		private LblDeserter lblDes;
		private LblAlien lblAlien;
		private LblMercenary lblMerc;
		private LblSmuggler lblSmug;

		public BoardPanel() {
			super();
			initBoard();
		}

		private void initBoard() {
			domeinController.startSpel();
			this.setBackground(Color.darkGray);
			displayBoard();
		}
		public String[][] getBoard(){
			return domeinController.getSpelbord(); // gets the board from the domainController as a 2D String Array
		}
		public void displayBoard() {
			this.removeAll();
			String[][] spelbord = getBoard();

			GridLayout grid = new GridLayout(spelbord.length, spelbord.length);
			int w = grid.getColumns() * 30;
			int h = grid.getRows() * 30;
			this.setSize(w, h);
			this.setLayout(grid);

			for (int row = 0; row < spelbord.length; row++) {
				for (int col = 0; col < spelbord[0].length; col++) {
					if (row == spelbord.length - 2
							&& col == spelbord[row].length - 2) {
						lblFinish = new LblFinish();
						this.add(lblFinish);
					} else {
						if (spelbord[row][col].equals("  ")) {
							lblEmpty = new LblEmpty();
							this.add(lblEmpty);
						} else
						if (spelbord[row][col].equals(" O")) {
							lblObst = new LblObst();
							this.add(lblObst);
						} else
						if (spelbord[row][col].equals(" H")) {
							lblMerc = new LblMercenary();
							this.add(lblMerc);
						} else
						if (spelbord[row][col].equals(" A")) {
							lblAlien = new LblAlien();
							this.add(lblAlien);
						} else
						if (spelbord[row][col].equals(" S")) {
							lblSmug = new LblSmuggler();
							this.add(lblSmug);
						} else
						if (spelbord[row][col].equals(" D")) {
							lblDes = new LblDeserter();
							this.add(lblDes);
						} else
						if (spelbord[row][col].equals(" P")) {
							lblPlayer = new LblPlayer();
							this.add(lblPlayer);
						}

					}
				}
			}
			this.validate();
		}
		
	}

My question:
I would create a second method updateBoard() to update the board without removing all of the components and re-adding them. (changes to the board are made outside of this class or the parent-class)
Is there a way to somehow only modify the player JLabel and opponent JLabel and update the gameBoard?

I was thinking along the lines of a double for-loop again that checks for the player/opponent?
Or should I look for a solution with getComponent() method and the like?

I know this isn't a 'Finish my homework plz plz plz' forum but I'm a bit stumped on how to approach this because I only got 3 hours of sleep and the project is due tomorrow so I really don't have a lot of time to start experimenting.

Any help, pointers in the right direction, suggestions, anything would be greatly appreciated.

Best regards,

Bloitz

[camickr]

I have no idea what your game does or what all your custom classes are but I would guess you can just use label.setIcon(...) method to update your board.

When you move a player, you would use label.setIcon(null) at the old position and then label.setIcon(player) at the new position. Then only those two labels will be repainted since nothing else in the game changes.

[mkjp2011]

Try this!

private void initBoard() {
			domeinController.startSpel();
			this.setBackground(Color.darkGray);
			displayBoard();
                        setVisible(true);
		}

[mkjp2011]

Anytime that you add components to a container you have to revalidate it