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Thread: Annoying null pointer exception in my code

  1. July 13th, 2012, 05:40 PM #1
    oyinig
    oyinig is offline
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    Default Annoying null pointer exception in my code

    I just wrote some codes in two classes just to obtain values fro form controls in lwuit but always return NPE. cCan somebody helpme please. Here is my snippet

    /*
 * Copyright (c)  2012, Zeeders and/or its affiliates. All rights reserved.
 */
 
 
import com.sun.lwuit.Display;
import com.sun.lwuit.io.NetworkManager;
import com.sun.lwuit.io.Storage;
import javax.microedition.midlet.*;
 
/**
 * MIDP version of the GP Calculator
 *
 * @author Oyinlola Israel
 */
public class calc extends MIDlet {
    private LocalApp app = new LocalApp();
 
    public void startApp() {
        Display.init(this);
        NetworkManager.getInstance().start();
        app.startApp();
    }
 
    public void pauseApp() {
    }
 
    public void destroyApp(boolean unconditional) {
    }
}

    That is the first class called clac.java

    /*
 * Copyright (c) 1990, 2011, Oracle and/or its affiliates. All rights reserved.
 */
 
 
import com.sun.lwuit.*;
import com.sun.lwuit.util.EventDispatcher;
import com.sun.lwuit.events.DataChangedListener;
import com.sun.lwuit.events.SelectionListener;
import java.io.IOException;
import com.sun.lwuit.animations.CommonTransitions;
import com.sun.lwuit.events.ActionEvent;
import com.sun.lwuit.events.ActionListener;
import com.sun.lwuit.io.ConnectionRequest;
import com.sun.lwuit.io.NetworkManager;
import com.sun.lwuit.io.services.ImageDownloadService;
import com.sun.lwuit.io.ui.SliderBridge;
import com.sun.lwuit.io.util.JSONParser;
import com.sun.lwuit.layouts.BorderLayout;
import com.sun.lwuit.layouts.BoxLayout;
import com.sun.lwuit.layouts.FlowLayout;
import com.sun.lwuit.list.DefaultListCellRenderer;
import com.sun.lwuit.list.ListModel;
import com.sun.lwuit.plaf.Border;
import com.sun.lwuit.plaf.Style;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;
import javax.microedition.io.Connector;
import javax.microedition.io.HttpConnection;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.AlertType;
 
 
 
 
/**
 * Implements the local business search UI of the makeover demo
 *
 * @author  Shai Almog
 */
public class LocalApp {
    /* Demo mode is activiated if network connection fails */
 
    TextField tf1, tf2, tf3, tf4, tf5, tf6, tf7, tf8, tf9, tf10, tf11, fname, fsub, tomail, fmail;
    ComboBox cb1, cb2, cb3, cb4, cb5, cb6, cb7, cb8, cb9, cb10, cb11;
    TextArea fbody;
    int cvalu;
    float gp;
 
    String rescom, gps;
 
    private boolean started;
    private Command exitCommand = new Command("Exit") {
        public void actionPerformed(ActionEvent ev) {
            Display.getInstance().exitApplication();
        }
    };
 
 /*    Command clacgp = new Command("Calculate GP") {
            public void actionPerformed(ActionEvent ev) {
                calculategp(Integer.parseInt(tf1.getText()), (String)cb1.getSelectedItem(), 
                        Integer.parseInt(tf2.getText()), (String)cb2.getSelectedItem(),
                        Integer.parseInt(tf3.getText()), (String)cb3.getSelectedItem(),
                        Integer.parseInt(tf4.getText()), (String)cb4.getSelectedItem(),
                        Integer.parseInt(tf5.getText()), (String)cb5.getSelectedItem(),
                        Integer.parseInt(tf6.getText()), (String)cb6.getSelectedItem(),
                        Integer.parseInt(tf7.getText()), (String)cb7.getSelectedItem(),
                        Integer.parseInt(tf8.getText()), (String)cb8.getSelectedItem(),
                        Integer.parseInt(tf9.getText()), (String)cb9.getSelectedItem(),
                        Integer.parseInt(tf10.getText()), (String)cb10.getSelectedItem(),
                        Integer.parseInt(tf11.getText()), (String)cb11.getSelectedItem()
 
                        );
 
            }
        };
        * 
        * 
        */
 
 
     public ComboBox createcombo()
    {
 
    ComboBox n = new ComboBox(new String[] {"A 5", "B 4", "C 3", "D 2", "E 1", "F 0"});
 
    return n;
    }
 
    public TextField createt()
    {
 
        TextField t = new TextField("0", 50);
        return t;
 
    }
 
    private void findgp1()
   {
 
           String m = (String)tf2.getText();
           System.out.println(m);
 
   }
 
 
     Command clacgp = new Command("Calculate GP") {
            public void actionPerformed(ActionEvent ev) {
                findgp1();
 
            }
        };
 
 
 
    private Command defaultThemeCommand = new Command("Set Theme 1") {
        public void actionPerformed(ActionEvent ev) {
            setTheme("/theme.res");
        }
    };
 
    private Command javaThemeCommand = new Command("Set Theme 2") {
        public void actionPerformed(ActionEvent ev) {
            setTheme("/LWUITtheme.res");
        }
    };
 
    private Command exit = new Command("Exit"){
        public void actionPerformed(ActionEvent ev) {
               Display.getInstance().exitApplication();
        }
 
    };
 
      private    Command mail = new Command("Send Mail"){
        public void actionPerformed(ActionEvent ev) {
               mailform();
        } 
      };
 
  private   Command back = new Command("Back"){
        public void actionPerformed(ActionEvent ev) {
            showMainForm();             
    }
  };
 
 
    private void setTheme(String name) {
        try {
            com.sun.lwuit.util.Resources res = com.sun.lwuit.util.Resources.open(name);
            com.sun.lwuit.plaf.UIManager.getInstance().setThemeProps(res.getTheme(res.getThemeResourceNames()[0]));
            Display.getInstance().getCurrent().refreshTheme();
        } catch(java.io.IOException err) {
             err.printStackTrace();
        }
    }
 
    private static Image getImage(String name) {
        try {
            return Image.createImage(name);
        } catch (IOException ex) {
            ex.printStackTrace();
            return null;
        }
    }
 
 
 
 
    public void startApp() {
        // distinguish between start and resume from pause
        if(!started) {
            started = true;
 
            // show your LWUIT form here e.g.: new MyForm().show();
            // this is a good place to set your default theme using
            // the UIManager class e.g.:
            try {
                com.sun.lwuit.util.Resources res = com.sun.lwuit.util.Resources.open("/theme.res");
                com.sun.lwuit.plaf.UIManager.getInstance().setThemeProps(res.getTheme(res.getThemeResourceNames()[0]));
            } catch(java.io.IOException err) {
                 err.printStackTrace();
            }
            showMainForm();
        }
    }
 
    private void showMainForm() {
        Form mainForm = new Form("CALCULATE GP");
        mainForm.setTransitionInAnimator(CommonTransitions.createFastSlide(CommonTransitions.SLIDE_HORIZONTAL, false, 400));
        mainForm.setTransitionOutAnimator(CommonTransitions.createFastSlide(CommonTransitions.SLIDE_HORIZONTAL, true, 400));
        mainForm.setLayout(new BoxLayout(BoxLayout.Y_AXIS));
        mainForm.addComponent(new Label("IST GRADE AND CREDIT LOAD"));
    final     TextField tf1 = createt();
        mainForm.addComponent(tf1);
    final     ComboBox cb1 = createcombo();
         mainForm.addComponent(cb1);
 
          mainForm.addComponent(new Label("2ND GRADE AND CREDIT LOAD"));
    final     TextField tf2 = createt();
        mainForm.addComponent(tf2);
    final     ComboBox cb2 = createcombo();
         mainForm.addComponent(cb2);
 
        mainForm.addComponent(new Label("3RD GRADE AND CREDIT LOAD"));
    final     TextField tf3 = createt();
        mainForm.addComponent(tf3);
 
    final     ComboBox cb3 = createcombo();
         mainForm.addComponent(cb3);
 
 
        mainForm.addComponent(new Label("4TH GRADE AND CREDIT LOAD"));
    final     TextField tf4 = createt();
        mainForm.addComponent(tf4);
   final      ComboBox cb4 = createcombo();
         mainForm.addComponent(cb4);
 
 
      mainForm.addComponent(new Label("5TH GRADE AND CREDIT LOAD"));
     final    TextField tf5 = createt();
        mainForm.addComponent(tf5);
      final   ComboBox cb5 = createcombo();
         mainForm.addComponent(cb5);    
 
 
    mainForm.addComponent(new Label("6TH GRADE AND CREDIT LOAD"));
     final    TextField tf6 = createt();
        mainForm.addComponent(tf6);
     final    ComboBox cb6 = createcombo();
         mainForm.addComponent(cb6);
 
    mainForm.addComponent(new Label("7TH GRADE AND CREDIT LOAD"));
     final    TextField tf7 = createt();
        mainForm.addComponent(tf7);
     final    ComboBox cb7 = createcombo();
         mainForm.addComponent(cb7);
 
   mainForm.addComponent(new Label("8TH GRADE AND CREDIT LOAD"));
     final    TextField tf8 = createt();
        mainForm.addComponent(tf8);
      final   ComboBox cb8 = createcombo();
         mainForm.addComponent(cb8);       
 
   mainForm.addComponent(new Label("9TH GRADE AND CREDIT LOAD"));
      final  TextField tf9 = createt();
        mainForm.addComponent(tf9);
    final     ComboBox cb9 = createcombo();
         mainForm.addComponent(cb9);       
 
    mainForm.addComponent(new Label("10TH GRADE AND CREDIT LOAD"));
    final     TextField tf10 = createt();
        mainForm.addComponent(tf10);
    final     ComboBox cb10 = createcombo();
         mainForm.addComponent(cb10);      
 
    mainForm.addComponent(new Label("11TH GRADE AND CREDIT LOAD"));
     final    TextField tf11 = createt();
        mainForm.addComponent(tf11);
    final     ComboBox cb11 = createcombo();
         mainForm.addComponent(cb11);      
 
 
 
        mainForm.addCommand(exitCommand);
        mainForm.addCommand(defaultThemeCommand);
        mainForm.addCommand(javaThemeCommand);
 
        mainForm.addCommand(clacgp);
        mainForm.addCommand(mail);
 
 
        mainForm.show();
    }
 
    private void exception(Exception ex) {
        ex.printStackTrace();
        Dialog.show("Error", "Error connecting to search service - Turning on DEMO MODE", "OK", null);
        showMainForm();
    }
 
   private int comboval(String ve)
    {
    char v = ve.trim().charAt(0);
 
        if (v == ('A'))
        {
        int cvalu = 5;  
        }
        else if (v ==('B'))
        {
        int cvalu = 4;  
        }
        else if (v == ('C'))
        {
        int cvalu = 3;  
        }
        else if (v == ('D'))
        {
        int cvalu = 2;  
        }
        else if (v == ('E'))
        {
        int cvalu = 1;  
        }
        if (v == ('F'))
        {
       int cvalu = 0;  
        }
 
    return cvalu;    
 
    }
 
 
 
 /*  private void findgp(int va1, String c1,int va2,String c2,int va3,String c3,int va3,String c3,int va5,String c5,int va6,String c6,int va7,String c7,int va8,String c8,int va9,String c9,int va10,String c10,int va11,String c11 )
   {
          int va1 = Integer.parseInt(tf1.getText());
      String c1 = (String)cb1.getSelectedItem();
      int cv1 = comboval(c1);
 
 
      int va2 = Integer.parseInt(tf2.getText());
      String c2 = (String)cb2.getSelectedItem();
        int cv2 = comboval(c2);
 
      int va4 = Integer.parseInt(tf4.getText());
      String c4 = (String)cb4.getSelectedItem();
        int cv4 = comboval(c4);
 
      int va3 = Integer.parseInt(tf3.getText());
      String c3 = (String)cb3.getSelectedItem();
        int cv3 = comboval(c3);
 
      int va5 = Integer.parseInt(tf5.getText());
      String c5 = (String)cb5.getSelectedItem();
        int cv5 = comboval(c5);
 
      int va6 = Integer.parseInt(tf6.getText());
      String c6 = (String)cb6.getSelectedItem();
        int cv6 = comboval(c6);
 
      int va7 = Integer.parseInt(tf7.getText());
      String c7 = (String)cb7.getSelectedItem();
        int cv7 = comboval(c7);
 
      int va8 = Integer.parseInt(tf8.getText());
      String c8 = (String)cb8.getSelectedItem();
        int cv8 = comboval(c8);
 
      int va9 = Integer.parseInt(tf9.getText());
      String c9 = (String)cb9.getSelectedItem();
        int cv9 = comboval(c9);
 
      int va10 = Integer.parseInt(tf10.getText());
      String c10 = (String)cb10.getSelectedItem();
        int cv10 = comboval(c10);
 
     int va11 = Integer.parseInt(tf11.getText());
      String c11 = (String)cb11.getSelectedItem();
        int cv11 = comboval(c11);
 
                int denum = va1+va2+va3+va4+va5+va6+va7+va8+va9+va10+va11;
 
                int num = cv1+cv2+cv3+cv4+cv5+cv6+cv7+cv8+cv9+cv10+cv11;
 
               float gp = num/denum;
 
                 gps = "Your Grade Point Average is  "+gp;
 
   }
   * 
   * 
   */
 
   private void getcom()
   {
 
 
    //   return rescom;
 
   }
 
 private void  calculategp(int va1, String c1,int va2,String c2,int va3,String c3,int va4,String c4,int va5,String c5,int va6,String c6,int va7,String c7,int va8,String c8,int va9,String c9,int va10,String c10,int va11,String c11 )
    {
 
        int s1 = c1.charAt(3);
        int s2 = c1.charAt(3);
        int s3 = c1.charAt(3);
        int s4 = c1.charAt(3);
        int s5 = c1.charAt(3);
        int s6 = c1.charAt(3);
        int s7 = c1.charAt(3);
        int s8 = c1.charAt(3);
        int s9 = c1.charAt(3);
        int s10 = c1.charAt(3);
        int s11 = c1.charAt(3);
 
  int num = ((va1*s1)+(va2*s2)+(va3*s3)+(va4*s4)+(va5*s5)+(va6*s6)+(va7*s7)+(va8*s8)+(va9*s9)+(va10*s10)+(va11*s11) );
  int den = va1+va2+va3+va4+va5+va6+va7+va8+va9+va10+va11; 
 
  float gp = num/den;
  String gps = "Your Calculated Grade Point Is  "+gp;
 
   if(gp>=4.5){ String rescom = "Your parent must hear about this. Having first class is not an easy thing. Congratulation";
 
   }
   else if (gp >=3.5){ String rescom = "Well, second class upper is not a bad deal but you can so much be better";
 
   } 
   else if (gp >=3.0){ String rescom = "What's up, why is is like this. Sure everything is alright?";
 
   } 
   else if (gp >=1.5){ String rescom = "Is this what you really saw on the board? If it is, it isn't a mistake, just keep silent and pretend.";
 
   } 
else if (gp < 1.5){ String rescom = "Believe me, you can find a better thing to do with your life that to waste precious moments at school. Pack your luggages from school and find something else to do. You might also be a billionaire";
 
} 
 
          Form res = createForm("GP RESULT"); 
           res.setTransitionInAnimator(CommonTransitions.createFastSlide(CommonTransitions.SLIDE_HORIZONTAL, false, 400));
        res.setTransitionOutAnimator(CommonTransitions.createFastSlide(CommonTransitions.SLIDE_HORIZONTAL, true, 400));
         res.setLayout(new BoxLayout(BoxLayout.Y_AXIS));
 
 
 
 
        Label re = new Label(gps);
        re.getStyle().setPadding(5, 5, 5, 5);
        re.getStyle().setBgColor(930);
 
 
        Image le = getImage("learn.png");
        Image logo = getImage("logo.png");
 
        Label com = new Label (rescom);
        com.getStyle().setPadding(10, 0, 0, 0);
        com.getStyle().setBgImage(le);
 
         res.addComponent(re);
         res.addComponent(com);
 
 
         res.addCommand(back);
         res.addCommand(mail);
 
         res.show();
    }   
 
 public void mailform()
 {
 Form mform = new Form("ZEEDERS MAIL");
 Label inst = new Label("SEND EASY MAIL");
 
 Label namel = new Label("Your Name");
 final TextField fname = new TextField(50);
 
 Label maill = new Label("Your Mail Address");
 final TextField fmail = new TextField(50);
 
 Label tomaill = new Label("To E-mail");
  final TextField tomail = new TextField(50);
 
 Label subl = new Label("Your Subject");
 final TextField fsub = new TextField(50);
 
 Label bodyl = new Label("Your Message Body");
 final TextArea fbody = new TextArea(5, 20, TextArea.ANY);
 
 mform.addComponent(inst);
 mform.addComponent(namel);
 mform.addComponent(fname);
 mform.addComponent(maill);
 mform.addComponent(fmail);
 mform.addComponent(tomaill);
 mform.addComponent(tomail);
 mform.addComponent(subl);
 mform.addComponent(fsub);
 mform.addComponent(bodyl);
 mform.addComponent(fbody);
 
 Command send = new Command("Send Mail")
 {
    public void actionPerformed(ActionEvent ev)
    {
    sendmail();
    }
 };
 
 mform.addCommand(send);
 
 Command nback = new Command("Back")
 {
    public void actionPerformed(ActionEvent ev)
    {
    showMainForm();
    }
 };
 
 mform.addCommand(nback);
 
 mform.show();
 
 } 
 
 public void sendmail()
 {
                     try{
 
        String name = fname.getText();
        String mail = fmail.getText();
        String to = tomail.getText();
        String sub= fsub.getText();
        String body = fbody.getText();
        String url="http://www.zeeders.com/app/app_mail_n.php?name="+name+"&mail="+mail+"&to="+to+"&subject="+sub+"&body="+body;
        url = url.replace(' ', '_');
 
 
	HttpConnection conn = (HttpConnection)Connector.open(url);
 
InputStream  ins = conn.openInputStream();
 
	InputStreamReader xmldata = new InputStreamReader(ins);
 
        if(xmldata.equals("true")){
           Dialog.show("Mail Sent", "Your Mail has been successfully sent", "OK", null);
        }
        else{
               Dialog.show("Error", "Your mail could not be delivered  to the receipient", "OK", null);
        }
 
         ins.close();
         conn.close();
       }
       catch(IOException ex){
 
           System.out.print("IOException occured");
 
       }
 }
 
 
    private Label createSubLabel(String text, int fgColor, Font f) {
        Label l = new Label(text);
        Style s = l.getStyle();
        s.setFgColor(fgColor);
        s.setFont(f);
        return l;
    }
 
 
 
 
    private Form createForm(String title) {
        Form f = new Form(title);
        f.getTitleComponent().setAlignment(Component.LEFT);
        f.setMenuCellRenderer(new DefaultListCellRenderer(false));
        return f;
    }
 
    /**
     * A list model that lazily fetches a result over the web if its unavailable
     */
 
 
 
 
 
 
 
}

    And this is the second class called LocalApp.java

    Although I have changed a lot of things but the central idea is just that I cant get values from the gui control.
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  3. July 13th, 2012, 08:06 PM #2
    Fubarable
    Fubarable is offline
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    Default Re: Annoying null pointer exception in my code

    The key bit of information is: which line causes the NPE to be thrown?
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