Re: modify button

"Andrew Thompson" <>
21 Nov 2006 17:39:56 -0800
porky008 wrote:

porky008 wrote:

This is my modify button can some one help me get it right?

     btnModify.addActionListener(new ActionListener(){
          public void actionPerformed(ActionEvent ae){


... is saying this when I run it
cannot find symbol
symbol: method DVD(java.lang.String,double,int)


Aaah.. It is probably that DVD(String, double) is a constructor,
right? To make a new instance of a DVD object.

In that case, the JVM thinks you are attempting to call a
DVD *method*, to clear its confusion, change it from..

  dvds.add(new DVD(tfTitle.getText(),

But a good *general* prinicple for debugging is not
to code like this in the first place. The code is attempting
to do too much in a single line, and it then becomes less
clear whcih part breaks. If I had problems with this code,
I might rewrite it something like this..

  String priceText = tfPrice.getText();
  // when in doubt, print out!
  System.out.println("priceText: '" + priceText + "'");
  double price = Double.parseDouble(priceText);
  System.out.println("price: " + price);
  DVD temp = new DVD(tfTitle.getText(), price);
  System.out.println("DVD: " + temp);
  dvds.add( temp );

...this way, would make it more clear, exactly
*where* the code was failing.

Note that a good debugger can do all that, much
quicker and without changing the code, but I think
it is important to understand how to plumb down
into a problem with minimal tools, to get training
for where/when to do it, and what to look for.

Andrew T.

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