Java txt box valadation?

joePC

OK I need to valadate a InputDialog box so it can only accept a number, so no letters or letters&numbers.

Heres what I got so far,

---

import javax.swing.JOptionPane;

public class valadation {

public static void main(String[] args) {

int num;
String choice;
int result;

choice = JOptionPane.showInputDialog(
"Enter Number");

while (choice == ""){
JOptionPane.showMessageDialog(null,
"Error, Numbers only");
}

while (choice == null){
JOptionPane.showMessageDialog(null,
"Error, Numbers only");

choice = JOptionPane.showInputDialog(
"Enter Number");

}


while (choice.matches("\\D+")){

JOptionPane.showMessageDialog(null,
"Error, Numbers only");

choice = JOptionPane.showInputDialog(
"Enter Number");
}


num = Integer.parseInt(choice);

result = square(num);

JOptionPane.showMessageDialog( null,
"Result = " + result, "Result",
JOptionPane.PLAIN_MESSAGE );

//System.out.print(result);

System.exit( 0 );

}

public static int square(int x){//Method Call

return x * 6;

}

}

---

OK it works if I enter a number, and gives the error message if I enter a letter, but any other combination it crashes???

Theres also a method you can ignore that. "Sorry"

Thanks loads in advance........

Thanks joePC

OfflerCrocGod

Jesus boy use the Force!!!....RegExp (Regular Expresions).

OfflerCrocGod

import javax.swing.JOptionPane;

public class valadation {

public static void main(String[] args) {

int num;
String choice;
int result;

choice = JOptionPane.showInputDialog("Enter Number");

while ( !choice.matches("[0-9]+" ) ){
JOptionPane.showMessageDialog(null,"Error, Numbers only");
choice = JOptionPane.showInputDialog("Enter Number");
}

num = Integer.parseInt(choice);
result = square(num);

JOptionPane.showMessageDialog( null,"Result = " + result, "Result", JOptionPane.PLAIN_MESSAGE );

System.exit( 0 );
}

public static int square(int x){//Method Call
return x * 6;
}
}

Should work, test it.

joePC

Thanks alot OfflerCrocGod,

Its always the small things

( !choice.matches("[0-9]+" ) )

Thanks joePC