如何将JPanels逐个添加到JPanel类型的数组中

Question

Currently, I'm facing a problem with this code, I want every time that I add a point to the map to add a JPanel to the array Panels (which is an array of JPanel).

I can't use for statement because I want to add 1 Jpanel per call (addPanel()), and also I'm facing a problem with the action listener,it only recognizes the first element in the array which is normal because the JPanel is not added to the array.

import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.awt.BorderLayout;

public class TestGrid02 extends JPanel  {

   private static final long serialVersionUID = 1L;

   protected static final Color SELECTION_COLOR = Color.pink;
   private Color originalColor = new Color(238,238,238) ;
   private static final Dimension PREF_SIZE = new Dimension(50, 50);
   public JPanel panel_2;
   public JPanel panel_3;
   public JFrame frame;
   public JTextField textField;
   public int maxX =10;
   public int maxY =10;
   public String name;
   JPanel[] panels = new JPanel[100];


   public TestGrid02() {
       initUI();
       createMap(panel_2,maxX ,maxY );

   }

   public final void initUI() {

       setLayout(new BorderLayout(0, 0));

        panel_2 = new JPanel();
        add(panel_2, BorderLayout.WEST);
        panel_2.setLayout(new GridLayout(10, 10, 1, 1));
        panel_2.setBackground(Color.GRAY);

        panel_3 = new JPanel(new BorderLayout(4, 4));
        add(panel_3, BorderLayout.LINE_END);
        panel_3.setBackground(Color.GREEN);

        JPanel controls = new JPanel(new GridLayout(0, 1, 0, 25));
        panel_3.add(controls, BorderLayout.PAGE_START);
        controls.setBackground(Color.CYAN);
        controls.setBorder(new EmptyBorder(40, 20, 20, 20));
        controls.add(new JTextField(10));
        controls.add(new JTextField(10));
        controls.add(new JButton("OK"));
   }


   public void createMap(JPanel a,int maxX,int maxY)  {    

       String [ ][ ] map = new String [maxX][maxY];

      for (int x = maxX-1; x>=0 ; x--) {

          for (int y = 0; y<maxY  ; y++) { 
               int i=x-1;
               int j=y-1;

              map [x][y] =  i + ","+  j ;
              System.out.println( map [x][y]); 
              addPanel(a,i,j);

}}}

   public void addPanel(JPanel a,int c, int d) {
              int i =0;
              panels[i] = new JPanel();        
              a.add(panels[i]);
              panels[i].setPreferredSize(PREF_SIZE);
              name = String.format("[%d, %d]", c,d);
              panels[i].setBackground(originalColor);
              panels[i].setName(name); 
              System.out.println(  "PanelName:"+panels[i].getName());
              //panels[i] =panels[i]; 
              //I need this statement to add the panel to the array panels

              panels[i].addMouseListener(new MouseAdapter() {
                @Override
                public void mouseEntered(MouseEvent e) {
                    panels[i].setBackground(Color.pink);
                    panels[i].add(new JLabel(panels[i].getName()));

                    panels[i].repaint();
                    panels[i].revalidate();

                }

                @Override
                public void mouseExited(MouseEvent e) {
                    panels[i].setBackground(originalColor);
                    panels[i].repaint();
                    panels[i].removeAll();

                }
            });

   }   


   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
             JFrame frame = new JFrame("Astar");
             frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
             frame.getContentPane().add(new TestGrid02());
             frame.setLocationRelativeTo(null);
             frame.pack();
             frame.setVisible(true);     

         }
      });
   }
}

Answer 1

it only recognizes the first element in the array which

That is because all you code references the variable "i" which never seems to change.

When adding (or removing) components from a visible GUI the basic code is:

panel.add(...);
panel.revalidate(); // to invoke the layout manager
panel.repaint();

Don't use an Array to hold the panels. You are restricting yourself to some hardcoded size. Instead use an ArrayList . Or the real question is do you even need an Array to hold the panels for future processing?

Your MouseListener code is wrong. To reference the component that generated the event your code should be:

JPanel panel = (JPanel)e.getSource();
panel.setBackground(...);