Redrawing JFrame lag/pop-in

Question

I have an issue with redrawing a JFrame that contains hundreds of JFrames inside it. I have an application that draws a "tile based" map and each tile is a JFrame. When I try to revalidate and redraw the JFrame you can visibly see random tiles appearing.

To combat this I have created a JPanel (blinds) that goes over the oldmap, and then the old map gets removed. Only then do I redraw. Then I add the new map and remove the "blind" and then re-draw again.

Is there a better way to do this. Some pop-in is still visible.

public void refreshMap(){
    JPanel blinds = new JPanel();
    blinds.setBackground(oCreator.getColorLight());
    blinds.setBounds(0, 0, length, height);
    add(blinds);
    if(currentMap != null){
        remove(currentMap);
    }
    revalidate();
    repaint();
    JPanel newMap = addMapPanel(map);
    newMap.setBounds(((length-absoluteMapLength)/2), ((height-absoluteMapHeight)/2), absoluteMapLength, absoluteMapHeight);
    remove(blinds);
    revalidate();
    repaint();
    add(newMap);
    currentMap = newMap;
}

Answer 1

If done right, there should be minimal delay in your change of tiles, but I'm not sure that your code and explanation can currently tell us where you're stuck. For example, run this code (my minimal example program) to see tiles changing color with minimal delay and no artifacts.

import java.awt.Color;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.*;

public class SquareGridTest extends JPanel {
   public static final Color[] COLORS = { Color.blue, Color.red, Color.yellow,
         Color.orange, Color.green, Color.cyan, Color.lightGray, Color.magenta,
         Color.white, Color.black };
   private static final Icon[] ICONS = new Icon[COLORS.length];
   private static final int ROWS = 20;
   private static final int COLS = 30;
   private static final int BI_WIDTH = 20;
   private static final int BI_HEIGHT = BI_WIDTH;
   private static final int TIMER_DELAY = 15;
   protected static final int NUMBER_TO_SWAP = 15;
   private JLabel[][] grid = new JLabel[ROWS][COLS];
   private Random random = new Random();

   static {
      for (int i = 0; i < ICONS.length; i++) {
         BufferedImage img = new BufferedImage(BI_WIDTH, BI_HEIGHT, BufferedImage.TYPE_INT_ARGB);
         Graphics g = img.getGraphics();
         g.setColor(COLORS[i]);
         g.fillRect(0, 0, BI_WIDTH, BI_HEIGHT);
         g.dispose();
         ICONS[i] = new ImageIcon(img);
      }
   }

   public SquareGridTest() {
      setLayout(new GridLayout(ROWS, COLS));
      for (int row = 0; row < grid.length; row++) {
         for (int col = 0; col < grid[row].length; col++) {
            JLabel label = new JLabel();
            int index = random.nextInt(COLORS.length);
            label.setIcon(ICONS[index]);
            add(label);
            grid[row][col] = label;            
         }
      }

      new Timer(TIMER_DELAY, new ActionListener() {

         @Override
         public void actionPerformed(ActionEvent evt) {
            for (int i = 0; i < NUMBER_TO_SWAP; i++) {
               int row = random.nextInt(ROWS);
               int col = random.nextInt(COLS);
               int iconIndex = random.nextInt(ICONS.length);
               grid[row][col].setIcon(ICONS[iconIndex]);
            }
         }
      }).start();
   }

   private static void createAndShowGui() {
      SquareGridTest mainPanel = new SquareGridTest();

      JFrame frame = new JFrame("SquareGridTest");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

---

For more detailed help with your code, and to help us better understand your problem, consider creating and posting your own minimal example program.