how do I change a user input string (jtextfield) into an int variable?

Question

I am doing my first java program with a GUI. I need to change the input from the user entered into a jTextField to a int variable i can use for work.

A better choice would be to use a field designed for the work like a `JSpinner` or `JFormattedField`... — MadProgrammer, Dec 10 '13 at 05:47

score 0 · Answer 1 · answered Dec 10 '13 at 05:43

0

Get the text and use Integer.parseInt(your String here);

answered Dec 10 '13 at 05:43

prmottajr

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int quarters = Integer.parseInt(jTextField); i get a syntax error on jTextField – sobey Dec 10 '13 at 05:45
You need to retrieve the String first. Try jTextField.getText() – PakkuDon Dec 10 '13 at 05:49

AJ. · Answer 2 · 2013-12-10T05:53:09.390

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int a = Integer.parseInt(jtextfield.getText());
// `jtextfield` will be your `JTextField` object

edited Dec 10 '13 at 05:53

answered Dec 10 '13 at 05:45

AJ.

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int quarters = Integer.parseInt(jtextfield.getText()); – sobey Dec 10 '13 at 05:49
@sobey what is your `JTextField` object name? – AJ. Dec 10 '13 at 05:51

score 0 · Answer 3 · answered Dec 10 '13 at 05:46

0

    JTextField jTextField=new JTextField(); // initialize textFild
    String str=jTextField.getText(); // get text value

Now you can convert this into int value.

    int val=Integer.parseInt(jTextField.getText());

answered Dec 10 '13 at 05:46

Ruchira Gayan Ranaweera

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score 0 · Answer 4 · edited Dec 10 '13 at 06:10

jtextfield.gettext() will return the entered String.. we can parse this string into integer

integer.parseInt(txtfield.getText());

but if we are typing values other than numbers 0-9 in the text filed it show java.lang.NumberFormatException

only numbers can be parsed into the integer

int num=Integer.parseInt("2")// is correct

int num=Integer.parseInt("two")//this will give numberformat exception

score 0 · Answer 5 · edited May 23 '17 at 10:27

int result = Integer.parseInt(jTextField.getText());

and apply

class MyIntFilter extends DocumentFilter {
   @Override
   public void insertString(FilterBypass fb, int offset, String string,
         AttributeSet attr) throws BadLocationException {

      Document doc = fb.getDocument();
      StringBuilder sb = new StringBuilder();
      sb.append(doc.getText(0, doc.getLength()));
      sb.insert(offset, string);

      if (test(sb.toString())) {
         super.insertString(fb, offset, string, attr);
      } else {
         // warn the user and don't allow the insert
      }
   }

   private boolean test(String text) {
      try {
         Integer.parseInt(text);
         return true;
      } catch (NumberFormatException e) {
         return false;
      }
   }

   @Override
   public void replace(FilterBypass fb, int offset, int length, String text,
         AttributeSet attrs) throws BadLocationException {

      Document doc = fb.getDocument();
      StringBuilder sb = new StringBuilder();
      sb.append(doc.getText(0, doc.getLength()));
      sb.replace(offset, offset + length, text);

      if (test(sb.toString())) {
         super.replace(fb, offset, length, text, attrs);
      } else {
         // warn the user and don't allow the insert
      }

   }

   @Override
   public void remove(FilterBypass fb, int offset, int length)
         throws BadLocationException {
      Document doc = fb.getDocument();
      StringBuilder sb = new StringBuilder();
      sb.append(doc.getText(0, doc.getLength()));
      sb.delete(offset, offset + length);

      if (test(sb.toString())) {
         super.remove(fb, offset, length);
      } else {
         // warn the user and don't allow the insert
      }

   }
}

(This class copied from Link)

PlainDocument doc = (PlainDocument) jTextField.getDocument();
doc.setDocumentFilter(new MyIntFilter());

This way you can restrict your input to numbers and get the string to integer by parsing it

how do I change a user input string (jtextfield) into an int variable?

5 Answers5