questions regarding the use of A* with the 15-square puzzle

Question

I\'m trying to build an A* solver for a 15-square puzzle.

The goal is to re-arrange the tiles so that they appear in their natural positions. You can only sli

Answer 1

check this
import javax.swing.*; 
import java.awt.*;
import java.awt.event.*;
import java.lang.Object;

class Puzzle extends JPanel implements ActionListener
{
    JButton[] b = new JButton[16];
    Puzzle()
    {
        b[0] = new JButton("4");
        b[1] = new JButton("11");
        b[2] = new JButton("5");
        b[3] = new JButton("9");
        b[4] = new JButton("1");
        b[5] = new JButton("10");
        b[6] = new JButton("12");
        b[7] = new JButton("13");
        b[8] = new JButton("15");
        b[9] = new JButton("14");
        b[10] = new JButton("3");
        b[11] = new JButton("2"); 
        b[12] = new JButton("7");
        b[13] = new JButton("8");
        b[14] = new JButton("6");
        b[15] = new JButton("");
        GridLayout grid = new GridLayout(4,4);
        setLayout(grid);
        for(int i=0;i<16;i++)
            add(b[i]);
        for(int i=0;i<16;i++)
            b[i].addActionListener(this);
    }
    public void actionPerformed(ActionEvent e)
    {
        /*if(e.getSource()==b[11])
        {
            if(b[15].getText()=="")
            {
                b[15].setText("");
            }
        }
        else if(e.getSource()==b[3])
        {
            if(b[2].getText()=="")
            {
                b[2].setText("");
            }
        }*/
        for(int i=0;i<16;i++)
        {
            System.out.println(e.getSource());
            if(e.getSource()==b[i])
            {
                if(i==5 || i==6 || i==9 || i==10)
                {   
                    if(b[i-1].getText()=="")
                    {
                        b[i-1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i+1].getText()=="")
                    {
                        b[i+1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i-4].getText()=="")
                    {
                        b[i-4].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i+4].getText()=="")
                    {
                        b[i+4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
                else if(i==4 || i==8)
                {   
                    if(b[i+1].getText()=="")
                    {
                        b[i+1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i-4].getText()=="")
                    {
                        b[i-4].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i+4].getText()=="")
                    {
                        b[i+4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
                else if(i==7 || i==11)
                {   
                    if(b[i-1].getText()=="")
                    {
                        b[i-1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i-4].getText()=="")
                    {
                        b[i-4].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i+4].getText()=="")
                    {
                        b[i+4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
                if(i==0)
                {   
                    if(b[i+1].getText()=="")
                    {
                        b[i+1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i+4].getText()=="")
                    {
                        b[i+4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
                if(i==3)
                {   
                    if(b[i-1].getText()=="")
                    {
                        b[i-1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i+4].getText()=="")
                    {
                        b[i+4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
                if(i==15)
                {   
                    if(b[i-1].getText()=="")
                    {
                        b[i-1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i-4].getText()=="")
                    {
                        b[i-4].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i+4].getText()=="")
                    {
                        b[i+4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
                if(i==12)
                {   
                    if(b[i+1].getText()=="")
                    {
                        b[i+1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i-4].getText()=="")
                    {
                        b[i-4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
                if(i==1 || i==2)
                {   
                    if(b[i+1].getText()=="")
                    {
                        b[i+1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i-1].getText()=="")
                    {
                        b[i-1].setText(b[i].getText());
                        b[i].setText("");
                    }                   
                    else if(b[i+4].getText()=="")
                    {
                        b[i+4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
                if(i==13 || i==14)
                {   
                    if(b[i+1].getText()=="")
                    {
                        b[i+1].setText(b[i].getText());
                        b[i].setText("");
                    }
                    else if(b[i-1].getText()=="")
                    {
                        b[i-1].setText(b[i].getText());
                        b[i].setText("");
                    }                   
                    else if(b[i-4].getText()=="")
                    {
                        b[i-4].setText(b[i].getText());
                        b[i].setText("");
                    }
                }
            }
        }
        //System.out.println(e.getActionCommand());
        }

    public static void main(String[] args)
    {
        JFrame frame = new JFrame("15-Puzzle");             

        //frame.setContentPane(panel);

JComponent newContentPane = new Puzzle();
        //newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);





        //panel.add(button);  
        frame.setSize(400,400);


        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}