Getting a numeric value form a text field

Question

SOLVED: I'm currently working on a program using Netbeans(JFrames) and I need to get a numeric value form a text field by using one of the '.get'.

NEW PROBLEM: When doing the 'if statement' of the contactumber it is giving me an error saying that an int cannot be dereferenced. Any suggestions ?

    namevalidation.setText(""); //Set text for the label
    surnamevalidation.setText(""); //Set text for the label
    contactvalidation.setText(""); //Set text for the label

    String name = namefield.getText(); //Get text form a textfield
    String surname = surnamefield.getText(); //Get text form a textfield
    int contactnumber = Integer.parseInt(contactfield.getText()); //Getting the numeric value form the textfield


    boolean passed=true;

    if(name.isEmpty())//Checking if the name or surname is empty
    {
        namevalidation.setText("Please enter your name!");
        passed = false;
    }

    if(surname.isEmpty())
    {
        surnamefield.setText("Please enter your surname!");
        passed = false;
    }
    if(contactnumber.isEmpty()) //THIS IS GIVING ME AN ERROR
    {
        contactfield.setText("Please enter your number!");
        passed = false;
    }

Answer 1

You should use the Integer#parseInt method:

int contactnumber = Integer.parseInt(contactfield.getText());

The Integer#parseInt takes a String and converts it into the primitive int if it is a valid number. If the number isn't valid a NumberFormatException will be thrown.

Documentation Integer#parseInt :

/**
 * Parses the string argument as a signed decimal integer. The
 * characters in the string must all be decimal digits, except
 * that the first character may be an ASCII minus sign {@code '-'}
 * ({@code '\u005Cu002D'}) to indicate a negative value or an
 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
 * indicate a positive value. The resulting integer value is
 * returned, exactly as if the argument and the radix 10 were
 * given as arguments to the {@link #parseInt(java.lang.String,
 * int)} method.
 *
 * @param s    a {@code String} containing the {@code int}
 *             representation to be parsed
 * @return     the integer value represented by the argument in decimal.
 * @exception  NumberFormatException  if the string does not contain a
 *               parsable integer.
 */

Answer 2

Simplest way to do that will be to get it as a String and convert to a number using Integer.parseInt() method.

String contactNumberStr = contactfield.get();

if (contactNumberStr != null) {
    try {
        int contactNumber = Integer.parseInt(contactNumberStr);
    } catch (NumberFormatException e) {
        // contactfield is not having a number
    }
}