newbie college progammer needs help!

The problem is that the Integer.parseInt(String) method is throwing an exception because it cannot find a way to convert the String it is given into an integer.

My guess is that you are creating the window, then using getText() to get the text from the field, then converting it to an integer (is this what you are doing?).

The getText() method does not wait for the user to enter text into the field if there is none there. It just grabs whatever the text field contains. The instant the window shows up, this is an empty string. Which then gets parsed to find an int (this doesn't work).

If you want your program to respond only after a user enters text into a field, you'll need to use ActionListeners. There's a little too much material for me to explain them right here, but it gives you something to search the web for. Basically, an ActionListener will provide methods that get called when events take place involving your text field (such as the user pressing the 'enter' key in it). You can then fill in the code inside these methods to respond to actions the way you want (get the string and try to make it into an int).

Also, a classic java programming mistake is to create a listener and not register it. Make sure you register it. (You won't know what that means until you've looked action listeners up)

Even after you set this up, if a user enters a bad (non-integer) string it will still crash the program. There are many ways to fix that, but you probably don't have to worry about them now.

logic_bomba at 2007-7-13 3:36:39 >

>a classic java programming mistake is to create

> a listener and not register it.

What exactly to you mean by 'registering' it? here's some code for what i've done w/ the action listener:

ok = new JButton("Bet");

ok.addActionListener(this);

public void actionPerformed(ActionEvent e)

{

//guiBet = Integer.parseInt(betStr);

if(e.getActionCommand() == "Bet")

{

guiBet = Integer.parseInt(betAmt.getText());

if(guiBet <= moneyAmt && guiBet > 0)

{

setVisible(false);

}

else

{

JOptionPane.showMessageDialog(this,"Your bet must be less than or equal to" + getMoneyAmt(), "Invalid Bet", JOptionPane.WARNING_MESSAGE);

}

}

}

Kruser14a at 2007-7-13 3:36:39 >

The addActionListener part registers it. That's what I meant. It's the part that people always forget and then they scratch their heads and wonder why it doesn't work. Most people have done it before. At least I know I have.

It all looks good to me. One little tip: be really careful about using the == operator with String objects. Using str1.equals( str2 ) is probably a better choice in most cases. This little program demonstrates why:

public class Strings {

public static void main( String args[] ) {

String s1 = "hello";

String s2 = "hello";

if( s1 == s2 ) {

System.out.println( "test 1 passed" );

}

s1 = new String( "hello" );

if( s1 == s2 ) {

System.out.println( "test 2 passed" );

}

}

}

Only the first message gets printed. In your situation == works, but it may not always do what you want. Not a big deal at all though.

logic_bomba at 2007-7-13 3:36:39 >

guiBet should be of type 'int', which would mean it cannot be causing the problem. If it was type 'Integer', that could cause a problem.

The getText() method from a text component doesn't return null. It will always return a String as far as I know.

That narrows it down to betAmt. I don't know what type betAmt is, but has it been initialized?

SomeType betAmt = new SomeType( <arguments> );

logic_bomba at 2007-7-13 3:36:39 >