strange refreshing behavior

[diggitydoggz]

Hey guys, been working on my hangman project. I created a method to set the text of two sets of JLabels. The first one I set as an array of JLabels, each label representing one letter the chosen word for the game, and the second one is simply a map<String, JLabel> of the whole alphabet. I added each of these labels to a JPanel with FlowLayout, and then added these to a JPanel with GridLayout which I placed in the southern region of the frame. I added everything to the frame first before adding the JLabels to them because I wanted the whole frame to appear before I prompted for the game word.

However there is a strange problem. Even though I am using repaint on both of the JPanels AND on the frame, the letters do not appear unless I resize the window. I thought repaint was supposed to fix this problem but apparently it doesn't. Why is it that the letters appear after I resize it but not immediately?

Here is my code so far:

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*; //for map

public class Hangman {
  public static void main(String[] args) {
    Hangman hangman = new Hangman();
  }
  
  JFrame frame = new JFrame();
  JLabel winLabel;
  JButton bNew;
  JPanel south1;
  JPanel south2;
  JPanel south3;
  JPanel south4;
  JPanel south;
  JLabel[] wordArray;
  //JLabel[] abcArray;
  Map<String, JLabel> abcMap;
  
  private int tries = 0;
  private int wrong = 0;
  
  public Hangman() {
    HangmanPanel hPanel = new HangmanPanel();
    hPanel.setPreferredSize(new Dimension(400, 300));
    abcMap = new HashMap<String, JLabel>();
    
    winLabel = new JLabel("");
    bNew = new JButton("New");
    
    south1 = new JPanel(new FlowLayout());
    south1.setForeground(Color.WHITE);
    south1.setBackground(Color.WHITE);
    
    south2 = new JPanel(new FlowLayout());
    south2.setBackground(Color.WHITE);
    south2.add(winLabel);
    
    south3 = new JPanel(new FlowLayout());
    south3.setBackground(Color.WHITE);
    
    south4 = new JPanel(new FlowLayout());
    south4.setBackground(Color.GRAY);
    south4.add(bNew);
    
    south = new JPanel(new GridLayout(4, 1));
    
    south.add(south1);
    south.add(south2);
    south.add(south3);
    south.add(south4);
    
    frame.setLayout(new BorderLayout());
    frame.setTitle("Hangman");
    frame.setSize(new Dimension(400,400));
    frame.setLocationRelativeTo(null);
    frame.add(hPanel, BorderLayout.CENTER);
    frame.add(south, BorderLayout.SOUTH);
    
    frame.pack();
    
    frame.setVisible(true);
    
    String gameWord = getWord();
    int length = gameWord.length();
    wordArray = new JLabel[length];
    createBoard(gameWord, length);
  }
  
  private void createBoard(String gameWord, int length) {
    for(int x = 0; x < length; x++) {
      wordArray[x] = new JLabel("" + gameWord.charAt(x));
    }
    
    for(int x = 0; x < 26; x++) {
      //abcArray[x] = new JLabel("" + (char)(x + 97));
      abcMap.put("" + (char)(x + 97), new JLabel("" + (char)(x + 97)));
    }
    
    for(int x = 0; x < length; x++) {
      south1.add(wordArray[x]);
    }
    
    for(int x = 0; x < 26; x++) {
      //south3.add(abcArray[x]);
      south3.add(abcMap.get("" + (char)(x + 97)));
    }
    
    south1.repaint();
    south3.repaint();
    south.repaint();
    frame.repaint();
  }

  private String getWord() {
    return JOptionPane.showInputDialog(frame, "Please enter word.");
  }
}



And here is the other class:



import javax.swing.*;
import java.awt.*;

public class HangmanPanel extends JPanel {
  public void paintComponent(Graphics g) {
    super.paintComponent(g);
    setBackground(Color.WHITE);
  }
}

[Fubarable]

Your posted code is incomplete. You may wish to read up on how to create and post an SSCCE to these forums. This will allow us to compile and run a small program that illustrates your problem.

My other suggestion: have you tried revalidating your JPanels?

edit:
adding this:

class HangmanPanel extends JPanel
{

}

to the bottom of your Hangman class allows your code to be compilable making it an SSCCE. You were almost there. ;)

[Fubarable]

Edit:
and in fact that should work. If you replace:

    south1.repaint();
    south3.repaint();
    south.repaint();
    frame.repaint();

with

    south.revalidate();

you may be pleasantly surprised.

[diggitydoggz]

Code edited.

I just tried revalidate. Thanks man. That worked. Why is it that repaint didn't work in this situation and that revalidate did? The API is so confusing... said something about a deferred automatic layout??

[Fubarable]

repaint just tells the component to repaint itself. revalidate tells the container's layout manager to relayout the components on the container. If you've added or changed components in a container, you should call revalidate else there's nothing there to repaint. repaint is also needed at times, especially if you remove components from a container.