Number from text box

[fifersheep]

Hi, there, very new to Java. I'm looking to get a number from a text box, then use the number in a calculation, and then put the answer into another text box.

JButton convertButton = new JButton ("Convert to Fahrenheit");
final JTextField celsiusText = new JTextField ("Enter temperature in Celsius to convert");
final JTextField fahrenheitText = new JTextField (" ");

JPanel buttons = new JPanel();
buttons.setLayo ut (new FlowLayout());

buttons.add (convertButton) ;

setTitle("Doubl er Frame");
setLayout(new BorderLayout()) ;
add(fahrenheitT ext, BorderLayout.SO UTH);
add(buttons, BorderLayout.CE NTER);
add(celsiusText , BorderLayout.NO RTH);

convertButton.a ddActionListene r (new ActionListener( )
{
public void actionPerformed ( ActionEvent e)
{

fahrenheit = (9/5)* + 33.8;
fahrenheitText. setText(Tempera ture in Fahrenheit: " + fahrenheit);
}
});

This is the main part of the code, I'm very confused and can't figure out whats wrong.

Hope you guys can spot my mistake.

I get an answer of 33.8, no matter what I enter in the first text box.

Would much appreciate help. Thanks!

[sukatoa]

Hi, there, very new to Java. I'm looking to get a number from a text box, then use the number in a calculation, and then put the answer into another text box.

JButton convertButton = new JButton ("Convert to Fahrenheit");
final JTextField celsiusText = new JTextField ("Enter temperature in Celsius to convert");
final JTextField fahrenheitText = new JTextField (" ");

JPanel buttons = new JPanel();
buttons.setLayo ut (new FlowLayout());

buttons.add (convertButton) ;

setTitle("Doubl er Frame");
setLayout(new BorderLayout()) ;
add(fahrenheitT ext, BorderLayout.SO UTH);
add(buttons, BorderLayout.CE NTER);
add(celsiusText , BorderLayout.NO RTH);

convertButton.a ddActionListene r (new ActionListener( )
{
public void actionPerformed ( ActionEvent e)
{

fahrenheit = (9/5)* + 33.8;
fahrenheitText. setText(Tempera ture in Fahrenheit: " + fahrenheit);
}
});

This is the main part of the code, I'm very confused and can't figure out whats wrong.

Hope you guys can spot my mistake.

I get an answer of 33.8, no matter what I enter in the first text box.

Would much appreciate help. Thanks!

If (9/5) is A
and 33.8 is B

the formula is A * celsiusvalue + B
since celsiusvalue is 0... A * celsiusvalue always returns 0...
That is why 33.8.....

1. Please post your code with codetags.
2. Someone may attempt to test your code, but your code is not complete....
3. You forgot to set the size of the frame.
4. fahrenheit is what Data type?
5. Having the input String to Double
- Get the String value of celsiusText
- Use Double.parseDou ble(String) for Double Conversion.... or float
- Add the value into your formula....
6. Download the Java Core API... It is useful...
7. Good luck.

sukatoa...

[fifersheep]

Ok this is my code in full now:

import javax.swing.*;
import javax.swing.JOp tionPane;
import java.awt.*;
import java.awt.event. *;

public class Temperature {

public static void main(String[] args) {

tempConvert buttonFrame = new tempConvert();
buttonFrame.set Size(350,120);
buttonFrame.set Location(250,10 0);
buttonFrame.set Visible(true);
}
}

class tempConvert extends JFrame{

//Stores default temperature numbers
double celsius = 1;
double fahrenheit = 33.8;

public tempConvert ()
{
JButton convertButton = new JButton ("Convert to Fahrenheit");
final JTextField celsiusText = new JTextField ("Enter temperature in Celsius to convert");
final JTextField fahrenheitText = new JTextField (" ");

JPanel buttons = new JPanel();
buttons.setLayo ut (new FlowLayout());

buttons.add (convertButton) ;

//creates layout of window
setTitle("Doubl er Frame");
setLayout(new BorderLayout()) ;
add(fahrenheitT ext, BorderLayout.SO UTH);
add(buttons, BorderLayout.CE NTER);
add(celsiusText , BorderLayout.NO RTH);

//states what to do when button is pressed
convertButton.a ddActionListene r (new ActionListener( )
{
public void actionPerformed ( ActionEvent e)
{
celsius = Double.parseDou ble (celsiusText);
fahrenheit = (9/5)* + 33.8;
fahrenheitText. setText("Fahren heit is: " + fahrenheit);
}
});
}
}


and I still get "Error: parseDouble(jav a.lang.String) in java.lang.Doubl e cannot be applied to (javax.swing.JT extField)"

I don't know if I'm using the parse correctly...

[sukatoa]

Ok this is my code in full now:

import javax.swing.*;
import javax.swing.JOp tionPane;
import java.awt.*;
import java.awt.event. *;

public class Temperature {

public static void main(String[] args) {

tempConvert buttonFrame = new tempConvert();
buttonFrame.set Size(350,120);
buttonFrame.set Location(250,10 0);
buttonFrame.set Visible(true);
}
}

class tempConvert extends JFrame{

//Stores default temperature numbers
double celsius = 1;
double fahrenheit = 33.8;

public tempConvert ()
{
JButton convertButton = new JButton ("Convert to Fahrenheit");
final JTextField celsiusText = new JTextField ("Enter temperature in Celsius to convert");
final JTextField fahrenheitText = new JTextField (" ");

JPanel buttons = new JPanel();
buttons.setLayo ut (new FlowLayout());

buttons.add (convertButton) ;

//creates layout of window
setTitle("Doubl er Frame");
setLayout(new BorderLayout()) ;
add(fahrenheitT ext, BorderLayout.SO UTH);
add(buttons, BorderLayout.CE NTER);
add(celsiusText , BorderLayout.NO RTH);

//states what to do when button is pressed
convertButton.a ddActionListene r (new ActionListener( )
{
public void actionPerformed ( ActionEvent e)
{
celsius = Double.parseDou ble (celsiusText);
fahrenheit = (9/5)* + 33.8;
fahrenheitText. setText("Fahren heit is: " + fahrenheit);
}
});
}
}


and I still get "Error: parseDouble(jav a.lang.String) in java.lang.Doubl e cannot be applied to (javax.swing.JT extField)"

I don't know if I'm using the parse correctly...

parseDouble needs a parameter String....
That string maybe the string value of textfield......
textfield.getTe xt().... read about it....

That String will be used to convert the String into Double....
That Double will then be returned after the process.....

Where must the celsius be on the formula? hint...

The complete explaination is on the web....
you can google it.

sukatoa

[fifersheep]

parseDouble needs a parameter String....
That string maybe the string value of textfield......
textfield.getTe xt().... read about it....

That String will be used to convert the String into Double....
That Double will then be returned after the process.....

Where must the celsius be on the formula? hint...

The complete explaination is on the web....
you can google it.

sukatoa

hmmm... still cant get the String from the textbox, doesn't matter though mate, might just try it using an input box or something, I'm sure I'll make sense of it all on day, and thanks for the help anyway man, appreciate it!

Take care

[JosAH]

That constant 33.8 in your (linear) conversion formula is incorrect:

F = 9/5*C+32
C = 5/9*(F-32)

kind regards,

Jos

[r035198x]

That constant 33.8 in your (linear) conversion formula is incorrect:

F = 9/5*C+32
C = 5/9*(F-32)

kind regards,

Jos

I've given up trying to guess where the OP got 33.8 from.