Format measurement field with Jformattedtextfield

Question

I’m trying to create a field to take measurements, I wanted to apply a mask so that it would look like this:

The field already starts with 0.00, then if you type value it keeps formatting.

And when I set back the values in the field, it did not lose the formatting.

I tried some things as it is before : https://stackoverflow.com/questions/14876695/make-jformattedtextfield-accept-decimal-with-more-than-3-digits/14876889#14876889

however the result is different than I expected. I tried to base myself on monetary fields taken from the internet, but also did not succeed.

what I did:

import java.math.BigDecimal;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JPanel;
import static javax.swing.SwingConstants.RIGHT;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
import javax.swing.text.AttributeSet;
import javax.swing.text.PlainDocument;

public class Main extends JFrame {

    private JPanel jpn = new JPanel();
    private Medida medida = new Medida();

    public Main() {

        jpn.add(medida);
        add(jpn);

        pack();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    }

    public static void main(String arg[]) {
        new Main().setVisible(true);
    }
}

class Medida extends JFormattedTextField implements CaretListener {

    public Medida() {

        setColumns(5);
        this.setDocument(new MeuDocument(4));
        setHorizontalAlignment(RIGHT);
        addCaretListener(this);
        setText("0,00");
        getCaret().setDot(getText().length());
    }

    @Override
    public void caretUpdate(CaretEvent e) {
        if (getCaret().getMark() != getText().length()) {
            getCaret().setDot(getText().length());
        }
    }

    public BigDecimal getValor() {
        return new BigDecimal(getText().replace(".", "").replace(",", "."));
    }

    public void setValor(BigDecimal valor) {
        setText(valor.toString());
    }

    class MeuDocument extends PlainDocument {

        private Integer tamanho;

        public MeuDocument(int tamanho) {
            this.tamanho = tamanho + 1; //tem que contar o separador de decimal (,)
        }

        @Override
        public void insertString(int offs, String str, AttributeSet a) {
            try {
                Pattern padrao = Pattern.compile("[0123456789]");
                Matcher matcher = padrao.matcher(str);
                String valorAtual = getText(0, getLength()).trim().replace(".", "").replace(",", "");
                str = str.trim().replace(",", ".");

                /*NumberFormat nf = NumberFormat.getCurrencyInstance();
                String valorFormatado = nf.format(valor).replace("R$ ", "");
                StringBuffer strBuf = new StringBuffer(valorFormatado);

                valorFormatado = valorFormatado.replace(".", "").replace(",", "").replace("-", ""); //retira tudo o que não for dígito para poder verificar o tamanho.

                if ((tamanho != null) && (valorFormatado.length() >= tamanho)) {
                    return;
                }
                super.remove(0, getLength());
                super.insertString(0, strBuf.toString(), a);*/
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

}

Answer 1

As I mentioned in the comments, this answer already solves the problem by simply adding a setText("0,00"); in the field constructor. The mask will be applied anyway once you start typing something into it.

If you do not want the .(point) as fractional separator and yes the comma, just remove the excerpt below:

DecimalFormatSymbols otherSymbols = new DecimalFormatSymbols(getLocale());
otherSymbols.setDecimalSeparator('.');

format.setDecimalFormatSymbols(otherSymbols);