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Thread: Difficulty with string passing...

  1. #1
    Junior Member
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    Question Difficulty with string passing...

    Hey everyone,

    I am having trouble exiting a program normally, rather than it crashing whenever I click the 'cancel' button.

    This code here is an example of what i want to do/happen...

            double length = 0;  // passing into
            String user_input;  // passing from
            boolean valid = true;  //  to exit the loop (irrelevant) 
     
            do
            {
                user_input = JOptionPane.showInputDialog("Enter the length in metres: ");
     
                try
                { 
                    length = Double.parseDouble(user_input); // code to pass string into double.
                    valid = true;
                }
     
                catch(NullPointerException error) // catches the error when user clicks the 'cancel' button and exits the program normally.
                {
                    System.exit(0);
                }
    The code above works and doesn't crash or have syntax errors

    I am trying to implement this with the code below, but to no avail.
    public static void exampleMethod(String user_input)
        {   
            String choice;
     
         try
           {
            choice = String.parseString(user_input); //<--- No such thing?! WHY!?
           }
     
         catch(NullPointerException error) // catches the error when user clicks the 'cancel' button and exits the program normally.
           {
               System.exit(0);
           }

    It honestly doesn't bother me what the 'try' function does, it can do anything... or NOTHING i just want the program NOT to crash when i click the 'cancel' button. I even attempted to delete it but the compiler insists ('catch' with no 'try')

    I hope this is clear enough...
    Last edited by Destined; May 12th, 2011 at 06:14 AM. Reason: could be interpreted in more than one way.


  2. #2
    Junior Member
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    Default Re: Difficulty with string passing...

    Wow... I have been working on this problem for 36+ hours and I finally figured it out... It was a misunderstanding of the 'try' statement...

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