Nullpointer Execp in startApp()

[Christian V Petersen]

Hey Everybody Im new at J2ME prog.
My compiler, Netbeans 3.6, tells me that my startApp() func throws a null pointer execption and I can not figure out why...

Is it because there is no instance of my MIDlet ???
So if anyone could help it would be great....


The code looks like this:
/*
* Game.java
*
* Created on 3. marts 2005, 19:08
*/
package BackG;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
*
* @author Christian V Petersen
* @version
*This MIDlet creates the main menus and paths to the different game-functions
*The exact game-functionality is placed in ....
*/
public class Game extends MIDlet implements CommandListener
{
private boolean firstTime;

public String userName;
private static String Intial_Text = "Enter user name here - max 10 characters"; // initial text for input to username

//Commands
private Command BACK = new Command("Back",Command.BACK,0);
private Command EXIT = new Command("Exit",Command.EXIT,1);
private Command DONE = new Command("Done",Command.OK,1);
// all other commands are from List.getSelectedIndex()

private Command currentCommand = null;
private Displayable currentDisplayable;

//Dipslayables: menuLists and screens
private Display display;
private TextBox inputName;
private List mainMenu;
private List playMenu;
private List highscoreMenu;
private Form privateScore;
//private TextField userScore;
private Form top5;
//private TextField top5Score;
String userScore;
String top5Score;

// string arrays for menus
String main[] =
{
"Username","Highscore","Play"
};

String highscore[]=
{
"Private Score", "Top 5"
};

String play[]=
{
"Play online","Local"
};

public Game()
{
display = Display.getDisplay(this);

// Instantiate the menus; mainMenu is done in startApp()

highscoreMenu = new List("Highscore",Choice.IMPLICIT,highscore,null);
highscoreMenu.addCommand(BACK);
highscoreMenu.setCommandListener(this);

playMenu = new List("Chooce game",Choice.IMPLICIT,play, null);
playMenu.addCommand(BACK);
playMenu.setCommandListener(this);

userScore = "No scores stored"; // this temp, socres should be stored on device
top5Score = "No scores to see";

privateScore = new Form("Score");
privateScore.append(userScore);
privateScore.addCommand(DONE);
privateScore.setCommandListener(this);

top5 = new Form("Top 5 in the Wold!");
top5.append(top5Score);
top5.addCommand(DONE);
top5.setCommandListener(this);

firstTime = true;
}

public void pauseApp()
{
}

public void destroyApp(boolean unconditional)
{
// should be changed to support storage
inputName = null;
Intial_Text=null;
}

public void quit()
{
destroyApp(true);
notifyDestroyed();
}

public void startApp()
{

if(firstTime==true)
{
mainMenu = new List("Main Menu",Choice.IMPLICIT,main,null);
mainMenu.addCommand(EXIT); // no back command needed
mainMenu.setCommandListener(this);
display.setCurrent(mainMenu);

firstTime= false;
}
}

public void commandAction(Command c, Displayable d)
{
currentCommand = c;
currentDisplayable = d;

String com_type = currentCommand.getLabel();

//All the commands must be checked
if(com_type=="BACK")
{
if(currentDisplayable.equals(inputName) ||
currentDisplayable.equals(highscoreMenu) ||
currentDisplayable.equals(playMenu))
{
display.setCurrent(mainMenu); // show the mainMenu
}
}

else if(com_type=="Exit")
{
quit();
}

else if (c== List.SELECT_COMMAND)
{
if(currentDisplayable.equals(mainMenu)) // options from the mainMenu
{
switch (mainMenu.getSelectedIndex())
{
case 0:// if the shown list is Submenu1
display.setCurrent(inputName);
break;

case 1:// if the shown list is Submenu2
display.setCurrent(highscoreMenu);
break;

case 2:
display.setCurrent(playMenu);
break;

}
}

else if(currentDisplayable.equals(highscoreMenu)) //options from the highscoreMenu
{
switch (highscoreMenu.getSelectedIndex())
{
case 0:
display.setCurrent(privateScore);
break;

case 1:
display.setCurrent(top5);
break;

}
}

else if (currentDisplayable.equals(playMenu))
{
switch(playMenu.getSelectedIndex())
{
case 0:
//Play online
break;
case 1:
// Play local
break;
}
}
}

}//end commandAction
} // end Game.class

[rooster13]

I don't know, but I would try to set the firstTry = true when declaring the variable.... I seems that is the only thing that could cause the exception...

[hvogeler]

Hi, I copied your code to eclipse with nokia sdk. It compiles perfectly and runs on the emulator.
There is no nullpointer.

[Christian V Petersen]

Hey

I figure it out ...

I belive I created a project wish in the end should create a JAR file. When I pasted the code into an empty class there was no problem.

Thank you for the help