Testing whether an input is a number

Question

I have a program, that whenever you type something and hit enter, it prints it out in a window (it's basically a command prompt). However, due to a few problems with a calculator function I'm trying to add, if the user input is a number, I want it to totally ignore it

    input = new JTextField();
    input.setEditable(true);
    input.setForeground(Color.WHITE);
    input.setCaretColor(Color.WHITE);
    input.setOpaque(false);

    input.addActionListener(new ActionListener(){

        public void actionPerformed(ActionEvent e) {

            String text = input.getText();

            if (text.length() >= 1){

                print(text + "\n", false);

                doCommand(text);
                scrollBottom();
                input.selectAll();
            }

        }
    });

you suppose to check last char of string whether it is `int`or not. — SatyaTNV, Sep 30 '15 at 13:00
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possible duplicate of [How to check if a String is a numeric type in Java](http://stackoverflow.com/questions/1102891/how-to-check-if-a-string-is-a-numeric-type-in-java) — Mage Xy, Sep 30 '15 at 13:31

score 0 · Accepted Answer · answered Sep 30 '15 at 13:08

0

You could check if text is a number with a regex like that:

text.matches("[1-9][0-9]*");

I hope it helps.

answered Sep 30 '15 at 13:08

Leonid Glanz

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Testing whether an input is a number

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