how can I validate if what a user types is an integer or not

[kenrocks]

my problem is to ensure that what the user types for the index of an array is really a digit and not a letter...please answer a.s.a.p. thx:D

[JosAH]

Have a look at the 'static int parseInt(String s) throws NumberFormatException'
method in the Integer class. It throws an exception when the String doesn't
represent a valid int value.

kind regards,

Jos

[kenrocks]

In regard with your answer...how ill I know if the user typed a string value if it automatically converts it into an integer? Well the result I want to get is not an exception I just want to place the values in an if statement and if that statement states that they are not of equal data type...it will display a .setText message that I will indicate...

[JosAH]

Well the result I want to get is not an exception I just want to place the values in an if statement and if that statement states that they are not of equal data type...it will display a .setText message that I will indicate...

Of course you have to catch that mentioned exception and take the appropriate
action(s). The method does its part, you do the other part.

kind regards,

Jos

[kenrocks]

So I have to try and catch? Can u teach me the basics of that methods

[JosAH]

So I have to try and catch? Can u teach me the basics of that methods

Simply wrap that method call in a try ... catch block; if the 'try' part completes
succesfully your String represented a number; if the 'catch' clause is executed
your String didn't represent a valid int number; it's some sort of an if-else structure. Look:

String s= // your String value
int value; // the result of the method
try {
   value= Integer.parse(s);
   // here the String represented an int
}
catch (NumberFormatException nfe) {
   // here the String didn't represent an int
}
 

kind regards,

Jos