Output a double value with JOPtionPane

dicecca112 · Jan 29, 2007

I want this code

Code:

    public void setInvoiceAmount(double Amount)
    {
                
        if (getQuantity() < 0)
        {
            quantity = 0;
        }
        if (getPricePerItem() < 0)
        {
            pricePerItem = 0;
        }
        
        Amount = (getQuantity() * getPricePerItem()); 
        
    }

    public double getInvoiceAmount()//method to print out InvoiceAmount
    {
        
        return Amount;
        
    }

to output a GUI window like this code does

Code:

    public void setPricePerItem(int item)//set method for Price Per Item
    {
    
         String newItem =
            JOptionPane.showInputDialog("What is the price?");
         
             int pricePerItem = Integer.parseInt( newItem);
        
            item = pricePerItem;
    }

    public double getPricePerItem()//get method for Price Per Item
    {
        return pricePerItem;
    }

asusradeon · Jan 30, 2007

ok, what launguage is this ? looks like c++ or something..

Midnight Dream · Jan 30, 2007

It's java.

This code is all odd. Why do you need this:

Code:

    public double getPricePerItem()//get method for Price Per Item
    {
        return pricePerItem;
    }

When you call it in a location in which the pricePerItem seems to be accessible. Same as quantity.

Knacko · Jan 30, 2007

Midnight Dream said:
This code is all odd.

It's proper OO programming.

dicecca112 said:
I want this code

to output a GUI window like this code does

For interfaces, run through this:

http://java.sun.com/docs/books/tutorial/uiswing/

It should tell you all you need to know.

Midnight Dream · Jan 30, 2007

Knacko said:
It's proper OO programming.

I know what OO programming is. Please read a bit further into my statement next time, before making a condescending remark. I am saying its odd in the sense that he is making calls to variables in a function which he is accessing those same variables in. And, the variables themselves do not appear to be local, because they are not defined in that function, or (as far as can be seen) in the same class.

dicecca112 · Jan 30, 2007

its how the teacher wanted it done. Irregardless she didn't care that the function with the double didn't output a JOptionPane Window. And thanks for that link Knacko

Midnight Dream · Jan 30, 2007

dicecca112 said:
its how the teacher wanted it done. Irregardless she didn't care that the function with the double didn't output a JOptionPane Window. And thanks for that link Knacko

The function with the double itself would not output a JOptionPane, as it is only returning a value, which is a double. That double in itself being a value called from some other far reaches of the code.

Trombe · Jan 31, 2007

Midnight Dream said:
The function with the double itself would not output a JOptionPane, as it is only returning a value, which is a double. That double in itself being a value called from some other far reaches of the code.

Or in dicecca's case, called from a setter method of the same class.
BTW, don't be mean; the programming section is a safe zone for noobs and experts alike.

Knacko · Jan 31, 2007

Midnight Dream said:
I know what OO programming is. Please read a bit further into my statement next time, before making a condescending remark. I am saying its odd in the sense that he is making calls to variables in a function which he is accessing those same variables in. And, the variables themselves do not appear to be local, because they are not defined in that function, or (as far as can be seen) in the same class.

I did not mean for the remark to sound condescending, and I apologize that it did.

In OO programming (which is meant for medium to large scale projects), you want your code to be reliable and maintainable. I agree that if there is a single class, there is no reason to write the code that way. But if the code were to include many classes, it is essential. Suppose more code was added in calculating the pricePerItem (taxes, sales, etc). You'd have to update the entire code, replacing the variable call with a call to the method (that you'd have to create) With the updated pricing instructions.

The idea is that all variables will stay private, while the methods are public. Writing the code like this will save huge re-writes when the code expands. Teaching it this way will better prepare one for real programming.

asusradeon · Jan 31, 2007

ah java.. i cant help then sorry..

Immortal_Hero · Feb 13, 2007

I would just convert it to a string to put it in the pane.

Code:

String output = Double.toString(pricePerItem);

BLcK · Feb 14, 2007

Midnight Dream said:
I know what OO programming is. Please read a bit further into my statement next time, before making a condescending remark. I am saying its odd in the sense that he is making calls to variables in a function which he is accessing those same variables in. And, the variables themselves do not appear to be local, because they are not defined in that function, or (as far as can be seen) in the same class.

I dont see how he is condesending in any way

. You only write a get'er(or a get method) for private data. I would assume "pricePerItem" is private data thus its very formal to code such a function and usualy the case for encapsulation purposes. :beer:

Immortal_Hero said:
I would just convert it to a string to put it in the pane.

Code:

String output = Double.toString(pricePerItem);

well i guess that would work, but wouldnt it just be better to output it to a text field? instead of having to write an extra line of code?

usually something like this is discussed/assigned when you get to awt or atleast i did <_< Keep things simple, but if your curious look up the java API reference and lookup if "JOptionPane.showOutputDialog();" exists - that'd be my guess.

EDIT: found it! zOMG i still knoes some java! (i havent done java for a bit

) showMessageDialog

Immortal_Hero · Feb 14, 2007

You wonldn't even have to assign it to a String object you could just convert it to a string in the code for the JOptionPane as you created the pane.

BLcK · Feb 14, 2007

Immortal_Hero said:
I would just convert it to a string to put it in the pane.

Code:

String output = Double.toString(pricePerItem);

Immortal_Hero said:
You wonldn't even have to assign it to a String object you could just convert it to a string in the code for the JOptionPane as you created the pane.

eh? Am I missing something? I think your contradicting yourself: :eh?:

Code:

String output = Double.toString(pricePerItem);

This converts pricePerItem to a string and assigns it to output and yet you say you dont have to - clear contradiction to the highlighted in red. In purple, its not required to convert it to a string if you wanna put it in a pane

Immortal_Hero · Feb 15, 2007

I am saying just do the Double.toString(XXX) in the code for the JOptionPane.

Code:

JOptionPane.showMessageDialog(null, "alert", Double.toString(pricePerItem), JOptionPane.ERROR_MESSAGE);

Does this clear up what I was saying? Where the Double.toString(... is where you normally would put a message like "Hi I am Immortal_Hero!" I was saying you would not have to make a string then output the string like below:

Code:

String output = Double.toString(pricePerItem);
JOptionPane.showMessageDialog(null, "alert", output, JOptionPane.ERROR_MESSAGE);

Output a double value with JOPtionPane

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