Java

Java RSS

Help with GUI

Please support our Java advertiser: Programming Forums - DaniWeb Sister Site

Thread Solved

•

Join Date: Oct 2007

Posts: 17

Reputation: PL.P27 is an unknown quantity at this point

Solved Threads: 0

PL.P27

Offline

Newbie Poster

Help with GUI

Oct 22nd, 2007

Hi everybody, I'm new to GUI and was wondering if someone could help me with my fraction calculator if they input text in the fields or if they leave something blank. I'm not quite sure how to do that. Here's my code, and if someone could guide me to how to do it, I'd be very thankful.

Help with Code Tags

(Toggle Plain Text)

fractionNumeratorOne = (int)(Integer.parseInt(firstNumerator.getText()));
      fractionDenominatorOne = (int)(Integer.parseInt(firstDenominator.getText()));
      fractionNumeratorTwo = (int)(Integer.parseInt(secondNumerator.getText()));
      fractionDenominatorTwo = (int)(Integer.parseInt(secondDenominator.getText()));
      if (fractionDenominatorOne==0 || fractionDenominatorTwo==0)
      {
        JOptionPane.showMessageDialog(null, "Zero isn't the right number, it will equal a positive infinity","Error", JOptionPane.ERROR_MESSAGE);
       
      }
      if(fractionNumeratorOne==)      {
      	JOptionPane.showMessageDialog(null, "Zero isn't the right number, it will equal a positive infinity","Error", JOptionPane.ERROR_MESSAGE);
      }

•

Join Date: Dec 2006

Posts: 198

Reputation: nschessnerd is an unknown quantity at this point

Solved Threads: 8

nschessnerd nschessnerd is offline

Offline

Junior Poster

Re: Help with GUI

Oct 23rd, 2007

basically you need to check if they have a value. if the enter nothing then the string will be null or "". If you try to set a integer equal to null, you will get an exception, so you need to check the value of the fraction inputs before you turn them into integers.
do so this simly use an if statement

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
if(firstDenominator.getText().equals(""){
//handle null value
}
if(firstDenominator.getText().equals(""){
//handle null value
}

hope that helps

this.love(*);
&hea/rts;

•

Join Date: Oct 2007

Posts: 17

Reputation: PL.P27 is an unknown quantity at this point

Solved Threads: 0

PL.P27

Offline

Newbie Poster

Re: Help with GUI

Oct 23rd, 2007

Thanks a lot, what if they enter letters, how would I change the if statement?

•

Join Date: Dec 2006

Posts: 198

Reputation: nschessnerd is an unknown quantity at this point

Solved Threads: 8

nschessnerd nschessnerd is offline

Offline

Junior Poster

Re: Help with GUI

Oct 23rd, 2007

hmm,
There is no clean way i can think of, but you can do

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
try{
int num=Integer.parseInt(firstDenominator.getText());
//if it gets to here its valid
}catch(NumberFormatException e){
//invalid number
}
try{
int num=Integer.parseInt(firstDenominator.getText());
//if it gets to here its valid
}catch(NumberFormatException e){
//invalid number
}