Open and display image in MVC layout

Question

Hello!
I cant figure out how I shall do this in an MVC layout:
The program request user to open an image file that are then displayed in a JLabel
My setup at the moment resolve in a nullpointerexeption because it dont get any actual image file, but I dont understand what I have missed.
I can not post the whole code fo you to run because it is to big, so I post the part that are the most important. please have a look.
PicturePanel
//Import Java library
import javax.swing.*;
import java.awt.*;
public class PicturePanel extends JPanel {
     //Variables
     private ImageIcon picture;
     //Method to get information of the selected file
     PicturePanel (String fileName) {
          picture = new ImageIcon (fileName); //Get the filename
          int w = picture.getIconWidth(); //Get the image with
          int h = picture.getIconHeight(); //Get the image height
          //Set preferable size for the image (Use the properties for the selected image)
          setPreferredSize(new Dimension(w, h));
          setMinimumSize(new Dimension(w, h));
          setMaximumSize(new Dimension(w, h));
     //Method to draw the selected image
     protected void paintComponent(Graphics g) {
          super.paintComponent(g); //We invoke super in order to: Paint the background, do custom painting.
          g.drawImage(picture.getImage(), 0, 0, this); //Draw the image at its natural state
}From my model:
//Local attributes
     boolean check = false; //Used to see if a statement is true or not
     PicturePanel pp;
     JFileChooser fc;
     int returnVal;
//newFile in File menu
     public void newFile() {
          //Open a file dialog in users home catalog
          fc = new JFileChooser();
          //In response to a button click:
          returnVal = fc.showOpenDialog(pp);
          System.out.println("You pressed new in file menu");
     }From my controler:
//User press "New" in File menu
          else if (user_action.equals("New")) {
               //Call method in model class
               model.newFile();
               //Update changes
               if (model.returnVal == JFileChooser.APPROVE_OPTION) {
                    System.out.println("Hello1");
                    File f = model.fc.getSelectedFile();
                    if (model.pp != null)     
                         model.pp = new PicturePanel(f.getAbsolutePath());
                    System.out.println("Hello2");
                    //Display image (Here is line 83)
                    view.setImage_DisplayArea(model.pp);
                    System.out.println("Hello3");
          }From my view:
//Sets the image to be displayed on the image_display area (Here is line 302)
     public void setImage_DisplayArea(PicturePanel pp) {
          image_display.add(pp);
     }The complet error:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
     at java.awt.Container.addImpl(Container.java:1015)You pressed new in file menu
Hello1
Hello2
     at java.awt.Container.add(Container.java:351)
     at View_Inlupp2.setImage_DisplayArea(View_Inlupp2.java:302)
     at Control_Inlupp2.actionPerformed(Control_Inlupp2.java:83)
     at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1882)
     at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2202)
     at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
     at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
     at javax.swing.AbstractButton.doClick(AbstractButton.java:334)
     at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1050)
     at apple.laf.CUIAquaMenuItem.doClick(CUIAquaMenuItem.java:119)
     at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1091)
     at java.awt.Component.processMouseEvent(Component.java:5602)
     at javax.swing.JComponent.processMouseEvent(JComponent.java:3129)
     at java.awt.Component.processEvent(Component.java:5367)
     at java.awt.Container.processEvent(Container.java:2010)
     at java.awt.Component.dispatchEventImpl(Component.java:4068)
     at java.awt.Container.dispatchEventImpl(Container.java:2068)
     at java.awt.Component.dispatchEvent(Component.java:3903)
     at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4256)
     at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3936)
     at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3866)
     at java.awt.Container.dispatchEventImpl(Container.java:2054)
     at java.awt.Window.dispatchEventImpl(Window.java:1801)
     at java.awt.Component.dispatchEvent(Component.java:3903)
     at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
     at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:269)
     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:184)
     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:176)
     at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)Edited by: onslow77 on Dec 16, 2009 5:00 PM
Edited by: onslow77 on Dec 16, 2009 5:04 PM

Answer 1

Hello again!
Anyone that can help me figure out how to implement this in an MVC layout, I feel stuck.
I post a little program that open and display an image file so that you better can understand what I whant to do.
ShowImage
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.File;
import javax.swing.filechooser.*;
public class ShowImage extends JFrame{
     //Variables
     JFileChooser fc = new JFileChooser();
     PicturePanel pp = null;
     ShowImage () {
          super("Show"); //Title
          //Create the GUI
          JPanel top = new JPanel();
          add(top, BorderLayout.NORTH);
          JButton openBtn = new JButton("Open");
          top.add(openBtn);
          openBtn.addActionListener(new Listner());
          //Settings for the GUI
          setDefaultCloseOperation(EXIT_ON_CLOSE);
          pack();
          setVisible(true);
     class Listner implements ActionListener {
          public void actionPerformed(ActionEvent ave) {
               int answer = fc.showOpenDialog(ShowImage.this);
               if (answer == JFileChooser.APPROVE_OPTION){
                    File f = fc.getSelectedFile();
                    //Check
                    System.out.println(f);
                    System.out.println(pp);
                    if (pp != null)
                         remove(pp); //Clean so that we can open another image
                    //Check
                    System.out.println(pp);
                    //Set the PicturePanel
                    pp = new PicturePanel(f.getAbsolutePath());
                    //Check
                    System.out.println(pp);
                    //Add PicturePanel to frame
                    add(pp, BorderLayout.CENTER);
                    validate();
                    pack();
                    repaint();
     //Main
     public static void main(String[] args) {
          new ShowImage();
}PicturePanel
//Import Java library
import javax.swing.*;
import java.awt.*;
public class PicturePanel extends JPanel {
     //Variables
     private ImageIcon picture;
     //Method to get information of the selected file
     PicturePanel (String fileName) {
          picture = new ImageIcon (fileName); //Get the filename
          int w = picture.getIconWidth(); //Get the image with
          int h = picture.getIconHeight(); //Get the image height
          //Set preferable size for the image (Use the properties for the selected image)
          setPreferredSize(new Dimension(w, h));
          setMinimumSize(new Dimension(w, h));
          setMaximumSize(new Dimension(w, h));
     //Method to draw the selected image
     protected void paintComponent(Graphics g) {
          super.paintComponent(g); //We invoke super in order to: Paint the background, do custom painting.
          g.drawImage(picture.getImage(), 0, 0, this); //Draw the image at its natural state
}//The endEdited by: onslow77 on Dec 16, 2009 7:30 PM