0
import javax.swing.*;
import java.awt.GridLayout;
import java.awt.event.*;
import java.text.*;


public class TFE extends JFrame implements ActionListener
{
	
	
	public TFE()
	{
		str txtfNum1,txtfNum2,lblAnswer;
		 
		setLayout(new GridLayout(3,2,5,5));
		add(new JLabel("First Number:"));
		add(txtfNum1);
		add(new JTextField(10));
		add(new JLabel("Second Number:"));
		add(txtfNum2);
		add(new JTextField(10));
		add(new JLabel("Total Summation:"));
		add(lblAnswer);
		txtfNum1.addActionListener(this);
		txtfNum2.addActionListener(this);
		
	}
	public void actionPerformed(ActionEvent e)
	{
		String str;
		int val1,val2,total;
		str=txtfNum1.getText();
		if(str.equals(""))
		val1=0;
		
		else
			val1=Integer.parseInt(str);
		str=txtfNum2.getText();
		if(str.equals(""))
		val2=0;
		
		else
			val2=Integer.parseInt(str);
			total=val1+val2;
			lblAnswer.setText(""+total);	
		
	}
	
	public static void main(String[]args){
		
		
		TFE frame=new TFE();
		frame.setTitle("TextField Event");
	frame.setSize(300,350);
	frame.setLocationRelativeTo(null);
	frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	frame.setVisible(true);
	}
}

i am confused with the use of parsing...please help me to correct the program...i am new in java...
the errors generated are
--------------------Configuration: <Default>--------------------
C:\Documents and Settings\Administrator\Desktop\TFE.java:14: cannot find symbol
symbol : class str
location: class TFE
str txtfNum1,txtfNum2,lblAnswer;
^
C:\Documents and Settings\Administrator\Desktop\TFE.java:33: cannot find symbol
symbol : variable txtfNum1
location: class TFE
str=txtfNum1.getText();
^
C:\Documents and Settings\Administrator\Desktop\TFE.java:39: cannot find symbol
symbol : variable txtfNum2
location: class TFE
str=txtfNum2.getText();
^
C:\Documents and Settings\Administrator\Desktop\TFE.java:46: cannot find symbol
symbol : variable lblAnswer
location: class TFE
lblAnswer.setText(""+total);
^
4 errors

Process completed.

2
Contributors
7
Replies
8
Views
7 Years
Discussion Span
Last Post by JamesCherrill
0

Reading it a agin with my glasses on, you seem to want to use txtfNum1,txtfNum2,lblAnswer as fields on your form, so maybe you should declare them as JTextField

0

hey...got another problem..it can compile but cant execute????
Exception in thread "main" java.lang.NullPointerException
at java.awt.Container.addImpl(Container.java:1027)
at java.awt.Container.add(Container.java:935)
at javax.swing.JFrame.addImpl(JFrame.java:545)
at java.awt.Container.add(Container.java:352)
at TFE.<init>(TFE.java:18)
at TFE.main(TFE.java:53)

Process completed.
what is this statement mean????please tell me directly...i am very stupid in java programming...

0

Maybe you declared, but didn't initialise, your new textfield variables - you need something like

JTextField txtfNum1 = new JTextField ();

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