How to change the value of a JLabel in runtime?
- by user365465
I want to change the image a JLabel is viewing during runtime, but I keep getting NullPointerExceptions or nothing happens when I press the magic button that's supposed to do things. Is it even possible in Java?
Here is my code in its entirety:
import java.text.*;
import javax.swing.text.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class Shell implements ActionListener, MenuKeyListener
{
JFrame frame;
JWindow window;
JButton PSubmit;
JPanel pane1, pane2;
JRadioButton R1, R2, R3;
ButtonGroup PGroup;
JTabbedPane layout;
String result;
String border = "Border.png";
String DF = "Frame.png";
String list [];
Driver driver;
public Shell()
{
driver = new Driver();
list = new String [6];
}
public void setFrame()
{
frame = new JFrame("Pokemon Program 3 by Systems Ready");
frame.setSize(600, 600);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.getContentPane().setLayout(new BorderLayout());
}
public void frameLayout()
{
layout = new JTabbedPane();
JPanel pane1 = new JPanel();
JPanel pane2 = new JPanel();
JLabel label = new JLabel("Please choose the restrictions:");
JLabel imgLabel1 = new JLabel(new ImageIcon(border));
JLabel notiLabel1 = new JLabel("The Pokemon chosen with these restrictions are: ");
JLabel notiLabel2 = new JLabel("'No Restrictions': No restrictions for the kind of Pokemon chosen based on species or items.");
JLabel notiLabel3 = new JLabel("'Battle Revolution': All Pokemon must have unique items.");
JLabel notiLabel4 = new JLabel("'Battle Tower': All Pokemon must have unique items, Uber and Event Legendaries banned.");
JLabel label2 = new JLabel("Please choose possible Pokemon:");
pane1.add(label);
pearlButtons();
pane1.add(R1);
pane1.add(R2);
pane1.add(R3);
pane1.add(PSubmit);
pane1.add(notiLabel2);
pane1.add(notiLabel3);
pane1.add(notiLabel4);
pane1.add(imgLabel1);
pane1.add(notiLabel1);
JLabel pokeLabel1 = new JLabel(new ImageIcon(DF));
JLabel pokeLabel2 = new JLabel(new ImageIcon(DF));
JLabel pokeLabel3 = new JLabel(new ImageIcon(DF));
JLabel pokeLabel4 = new JLabel(new ImageIcon(DF));
JLabel pokeLabel5 = new JLabel(new ImageIcon(DF));
JLabel pokeLabel6 = new JLabel(new ImageIcon(DF));
pane1.add(pokeLabel1);
pane1.add(pokeLabel2);
pane1.add(pokeLabel3);
pane1.add(pokeLabel4);
pane1.add(pokeLabel5);
pane1.add(pokeLabel6);
pane2.add(label2);
layout.add("Pearl Version", pane1);
layout.add("SoulSilver Version", pane2);
frame.add(layout);
}
public void pearlButtons()
{
PGroup = new ButtonGroup();
R1 = new JRadioButton("No Restrictions", true);
R1.setActionCommand("N");
R1.setVisible(true);
R2 = new JRadioButton("Battle Revolution");
R2.setActionCommand("BR");
R2.setVisible(true);
R3 = new JRadioButton("Battle Tower");
R3.setActionCommand("B");
R3.setVisible(true);
PGroup.add(R1);
PGroup.add(R2);
PGroup.add(R3);
PSubmit = new JButton("Submit");
PSubmit.setActionCommand("pstart");
PSubmit.setVisible(true);
PSubmit.addActionListener(this);
}
public void pearlProcessing()
{
//The "list" array has a bunch of string names that get .png affixed to them (and I named the image files as such when I name them)
String file1 = list[0] + ".png";
String file2 = list[1] + ".png";
String file3 = list[2] + ".png";
String file4 = list[3] + ".png";
String file5 = list[4] + ".png";
String file6 = list[5] + ".png";
/*-------------------------------------------------------------------------------//
This is where the method's supposed to go to change the image...
I've tried pokeLabel = new JLabel(new ImageIcon(file1));, but that yields a NullPointerException.
//-----------------------------------------------------------------------------------*/
}
public static void main(String[] args)
{
Shell test = new Shell();
test.setFrame();
test.frameLayout();
test.frame.setVisible(true);
}
public void actionPerformed(ActionEvent e)
{
if ("pstart".equals(e.getActionCommand()))
{
result = PGroup.getSelection().getActionCommand();
if (result.equals("N"))
{
list = driver.Prandom();
pearlProcessing();
}
else
System.out.println("Not done yet! ;)");
}
}
public void menuKeyPressed(MenuKeyEvent e)
{
System.out.println("pressed");
}
public void menuKeyReleased(MenuKeyEvent e)
{
System.out.println("menuKeyReleased");
}
public void menuKeyTyped(MenuKeyEvent e)
{
System.out.println("menuKeyTyped");
}
}
