Cannot figure out why I'm getting these Errors

[Defiledgrave]

my code is posted below the program is to be very simple just just a button a choice box a text box and a canvas the user is to be able to select what item they want and then the price appears in the label....then the user is able to put in a quantity and when they hit order the program should calculate the price and display it nice and neat in the canvas....I'm new to Java and ...if this were C++ I could do it in an hour I just don't understand why it's not working...please someone help

thank you







import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
public class grocerystore extends Applet{

private Button order = new Button("Order");
private Label price = new Label("Your price will appear here");
private Choice food = new Choice();
private TextField quantity = new TextField();
double quantitySelected;
double eggs = 1.90;
double milk = 1.47;
double bread = 2.12;
double total;
display output = new display();

public void init() {
add(order);
add(price);
add(quantity);
add(food);
food.add("Select your food");
food.add("Eggs");
food.add("Milk");
food.add("Bread");
order.addActionListener(this);
food.addItemListener(this);
add(output);
output.setSize(250,100);
order.addActionListener(this)
food.addActionListener(this)
}

class display extends Canvas
implements ActionListener, ItemListener {
int itemSelected = food.getSelectedIndex();

public void actionPerformed(ActionEvent action) {
quantitySelected = new Double(quantity.getText()).doubleValue();



if (itemSelected==1)
total = quantitySelected * eggs;
if (itemSelected==2)
total = quantitySelected * milk;
if (itemSelected==3)
total = quantitySelected * bread;


}

public void itemStateChanged(ItemEvent event) {


if (itemSelected==1)
price.setText("The price of a dozen eggs is " + eggs);
if (itemSelected==2)
price.setText("The price of a quart of milk is " + milk);
if (itemSelected==3)
price.setText("The price of a loaf of bread is " + bread);
}

public void paint(Graphics g){
if (itemSelected==1){
g.drawString("You purchased " + quantitySelected + "dozen eggs",20,20);
g.drawString("for a total of " + total,20,30);
}
}

}

}

[BountyX]

whats the error?

[sykkn]

First thing I see is that you missed semicolons on the following lines:

order.addActionListener(this)
food.addActionListener(this)

[sykkn]

another thing ... quick paste into eclipse and it suggests that you cast "this" with (ActionListener) and (ItemListener) .... Also I think you may have meant addItemListener on the second food.add* line.

order.addActionListener((ActionListener)this);
food.addItemListener((ItemListener)this);
order.addActionListener((ActionListener)this);
food.addItemListener((ItemListener)this);


//edit ... left off the semicolons myself that time ;)

[Defiledgrave]

well......after an hour of staring and trying things I come to another dead end......thank you for the help before I appreciate it but now my applet doesn't initialize....and all I get is a blank rectangle I get no errors so I'm not sure what I'm doing wrong...I'll keep working at it but if someone finds something before I do I'd appreciate it a lot


Thank you in advance






import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
public class grocerystore extends Applet{

private Button order = new Button("Order");
private Label price = new Label("Your price will appear here");
private Choice food = new Choice();
private TextField quantity = new TextField();
double quantitySelected;
double eggs = 1.90;
double milk = 1.47;
double bread = 2.12;
double total;
display output = new display();

public void init() {
add(order);
add(price);
add(quantity);
add(food);
food.add("Select your food");
food.add("Eggs");
food.add("Milk");
food.add("Bread");
add(output);
output.setSize(250,100);
order.addActionListener((ActionListener)this);
food.addItemListener((ItemListener)this);
order.addActionListener((ActionListener)this);
food.addItemListener((ItemListener)this);

}

class display extends Canvas
implements ActionListener, ItemListener {
int itemSelected = food.getSelectedIndex();

public void actionPerformed(ActionEvent action) {
quantitySelected = new Double(quantity.getText()).doubleValue();



if (itemSelected==1)
total = quantitySelected * eggs;
if (itemSelected==2)
total = quantitySelected * milk;
if (itemSelected==3)
total = quantitySelected * bread;


}

public void itemStateChanged(ItemEvent event) {


if (itemSelected==1)
price.setText("The price of a dozen eggs is " + eggs);
if (itemSelected==2)
price.setText("The price of a quart of milk is " + milk);
if (itemSelected==3)
price.setText("The price of a loaf of bread is " + bread);
}

public void paint(Graphics g){
if (itemSelected==1){
g.drawString("You purchased " + quantitySelected + "dozen eggs",20,20);
g.drawString("for a total of " + total,20,30);
}
}

}

}

[BountyX]

Something is wrong with how you use the ActionListner().

//order.addActionListener((ActionListener)this);
//food.addItemListener((ItemListener)this);
//order.addActionListener((ActionListener)this);
//food.addItemListener((ItemListener)this);

in the init() method, those are cuasing the applet not to intialize correctly and why do you do it twice?

EDIT: I suspect that you are handleing the action events wrong.

[Defiledgrave]

Alright well I took out the extra two lines so they aren't in there twice and instead of using the keyword this I applied them to thier respective areas....price and output but it still won't initialize I even tried it keeping it with the keyword this and still no progress.......

order.addActionListener((ActionListener)output);
food.addItemListener((ItemListener)price);


order.addActionListener((ActionListener)this);
food.addItemListener((ItemListener)this);

niether way works :-(

EDIT----ok well I worked on it some more and I got the applet to initalize when I commented out the second line so I had
order.addActionListener((ActionListener)output);
//food.addItemListener((ItemListener)price);
it initialized but didn't do anything when I entered a int into the text box and hit the order button

I don't know why it won't initalize with the second line

[BountyX]

check how the action is processed, and make sure the html code is correctly calling the applet with all tags closed, personally i dont know why it wont intialize either, looks correct.

[Defiledgrave]

[BountyX]

if u get a solution post back so I can learn too :)

[Defiledgrave]

WOOOOO I figured it out....I got it to initialize and I got my choicebox to work whoohooo
now I just gotta work on manipulating my canvas to work when my button is pressed.....but it's 3 am and I've been working on this since midnight just like everyother night this week...thank you for all you help and Bounty here is the code

import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
public class grocerystore extends Applet{

private Button order = new Button("Order");
private Label price = new Label("Your price will appear here");
private Choice food = new Choice();
private TextField quantity = new TextField(3);
double quantitySelected;
double eggs = 1.90;
double milk = 1.47;
double bread = 2.12;
double total;
display output = new display();

public void init() {
add(order);
add(quantity);
add(food);
food.add("Select your food");
food.add("Eggs");
food.add("Milk");
food.add("Bread");
add(price);
add(output);
output.setSize(300,300);
food.addItemListener(this.output);
order.addActionListener(this.output);

}
class display extends Canvas
implements ActionListener, ItemListener {
public int itemSelected;

public void actionPerformed(ActionEvent action) {

quantitySelected = new Double(quantity.getText()).doubleValue();
itemSelected = food.getSelectedIndex();


if (itemSelected==1)
total = quantitySelected * eggs;
if (itemSelected==2)
total = quantitySelected * milk;
if (itemSelected==3)
total = quantitySelected * bread;

}

}

public void itemStateChanged(ItemEvent event) {
itemSelected = food.getSelectedIndex();


if (itemSelected==1)
price.setText("The price of a dozen eggs is " + eggs );
if (itemSelected==2)
price.setText("The price of a quart of milk is " + milk);
if (itemSelected==3)
price.setText("The price of a loaf of bread is " + bread);
}

public void paint(Graphics g){
if (itemSelected==1){
g.drawString("You purchased " + quantitySelected + "dozen eggs",50,50);
g.drawString("for a total of " + total,50,60);
}

}

}

[BountyX]

thnx :) glad to here you got it working

[WannaBe]