Decimal separator comma (',') with numberD

Question

The inputType numberDecimal in EditText uses the dot '.' as decimal separator. In Europe it's common to use a comma ',' instead. Even though my locale is set as german the decimal separator is still the '.'

Is there a way to get the comma as decimal separator?

Answer 1

I don't know why your answers are so complicated. If there's a bug in SDK you must override it or go around.

I have chosen the second way to solve that problem. If you format your string as Locale.ENGLISH and then put it to the EditText (even as an empty string). Example:

String.format(Locale.ENGLISH,"%.6f", yourFloatNumber);

Chasing that solution your result are compatible with the shown keyboard. Then float and double numbers work in typical for programming languages manner with dot instead of comma.

Answer 2

Martins answer won't work if you are instantiating the EditText programmatically. I went ahead and modified the included DigitsKeyListener class from API 14 to allow for both comma and period as decimal separator.

To use this, call setKeyListener() on the EditText, e.g.

// Don't allow for signed input (minus), but allow for decimal points
editText.setKeyListener( new MyDigitsKeyListener( false, true ) );

However, you still have to use Martin's trick in the TextChangedListener where you replace commas with periods

import android.text.InputType;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.method.NumberKeyListener;
import android.view.KeyEvent;

class MyDigitsKeyListener extends NumberKeyListener {

    /**
     * The characters that are used.
     *
     * @see KeyEvent#getMatch
     * @see #getAcceptedChars
     */
    private static final char[][] CHARACTERS = new char[][] {
        new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' },
        new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-' },
        new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '.', ',' },
        new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '.', ',' },
    };

    private char[] mAccepted;
    private boolean mSign;
    private boolean mDecimal;

    private static final int SIGN = 1;
    private static final int DECIMAL = 2;

    private static MyDigitsKeyListener[] sInstance = new MyDigitsKeyListener[4];

    @Override
    protected char[] getAcceptedChars() {
        return mAccepted;
    }

    /**
     * Allocates a DigitsKeyListener that accepts the digits 0 through 9.
     */
    public MyDigitsKeyListener() {
        this(false, false);
    }

    /**
     * Allocates a DigitsKeyListener that accepts the digits 0 through 9,
     * plus the minus sign (only at the beginning) and/or decimal point
     * (only one per field) if specified.
     */
    public MyDigitsKeyListener(boolean sign, boolean decimal) {
        mSign = sign;
        mDecimal = decimal;

        int kind = (sign ? SIGN : 0) | (decimal ? DECIMAL : 0);
        mAccepted = CHARACTERS[kind];
    }

    /**
     * Returns a DigitsKeyListener that accepts the digits 0 through 9.
     */
    public static MyDigitsKeyListener getInstance() {
        return getInstance(false, false);
    }

    /**
     * Returns a DigitsKeyListener that accepts the digits 0 through 9,
     * plus the minus sign (only at the beginning) and/or decimal point
     * (only one per field) if specified.
     */
    public static MyDigitsKeyListener getInstance(boolean sign, boolean decimal) {
        int kind = (sign ? SIGN : 0) | (decimal ? DECIMAL : 0);

        if (sInstance[kind] != null)
            return sInstance[kind];

        sInstance[kind] = new MyDigitsKeyListener(sign, decimal);
        return sInstance[kind];
    }

    /**
     * Returns a DigitsKeyListener that accepts only the characters
     * that appear in the specified String.  Note that not all characters
     * may be available on every keyboard.
     */
    public static MyDigitsKeyListener getInstance(String accepted) {
        // TODO: do we need a cache of these to avoid allocating?

        MyDigitsKeyListener dim = new MyDigitsKeyListener();

        dim.mAccepted = new char[accepted.length()];
        accepted.getChars(0, accepted.length(), dim.mAccepted, 0);

        return dim;
    }

    public int getInputType() {
        int contentType = InputType.TYPE_CLASS_NUMBER;
        if (mSign) {
            contentType |= InputType.TYPE_NUMBER_FLAG_SIGNED;
        }
        if (mDecimal) {
            contentType |= InputType.TYPE_NUMBER_FLAG_DECIMAL;
        }
        return contentType;
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end,
                               Spanned dest, int dstart, int dend) {
        CharSequence out = super.filter(source, start, end, dest, dstart, dend);

        if (mSign == false && mDecimal == false) {
            return out;
        }

        if (out != null) {
            source = out;
            start = 0;
            end = out.length();
        }

        int sign = -1;
        int decimal = -1;
        int dlen = dest.length();

        /*
         * Find out if the existing text has '-' or '.' characters.
         */

        for (int i = 0; i < dstart; i++) {
            char c = dest.charAt(i);

            if (c == '-') {
                sign = i;
            } else if (c == '.' || c == ',') {
                decimal = i;
            }
        }
        for (int i = dend; i < dlen; i++) {
            char c = dest.charAt(i);

            if (c == '-') {
                return "";    // Nothing can be inserted in front of a '-'.
            } else if (c == '.' ||  c == ',') {
                decimal = i;
            }
        }

        /*
         * If it does, we must strip them out from the source.
         * In addition, '-' must be the very first character,
         * and nothing can be inserted before an existing '-'.
         * Go in reverse order so the offsets are stable.
         */

        SpannableStringBuilder stripped = null;

        for (int i = end - 1; i >= start; i--) {
            char c = source.charAt(i);
            boolean strip = false;

            if (c == '-') {
                if (i != start || dstart != 0) {
                    strip = true;
                } else if (sign >= 0) {
                    strip = true;
                } else {
                    sign = i;
                }
            } else if (c == '.' || c == ',') {
                if (decimal >= 0) {
                    strip = true;
                } else {
                    decimal = i;
                }
            }

            if (strip) {
                if (end == start + 1) {
                    return "";  // Only one character, and it was stripped.
                }

                if (stripped == null) {
                    stripped = new SpannableStringBuilder(source, start, end);
                }

                stripped.delete(i - start, i + 1 - start);
            }
        }

        if (stripped != null) {
            return stripped;
        } else if (out != null) {
            return out;
        } else {
            return null;
        }
    }
}

Answer 3

You can use the following workaround to also include comma as a valid input:-

Through XML:

<EditText
    android:inputType="number"
    android:digits="0123456789.," />

Programmatically:

EditText input = new EditText(THE_CONTEXT);
input.setKeyListener(DigitsKeyListener.getInstance("0123456789.,"));

In this way Android system will show the numbers' keyboard and allow the input of comma. Hope this answers the question :)

Answer 4

Android has a built in number formatter.

You can add this to your EditText to allow decimals and commas: android:inputType="numberDecimal" and android:digits="0123456789.,"

Then somewhere in your code, either when user clicks save or after text is entered (use a listener).

// Format the number to the appropriate double
try { 
    Number formatted = NumberFormat.getInstance().parse(editText.getText().toString());
    cost = formatted.doubleValue();
} catch (ParseException e) {
    System.out.println("Error parsing cost string " + editText.getText().toString());
    cost = 0.0;
}

Answer 5

This is a known bug in the Android SDK. The only workaround is to create your own soft keyboard. You can find an example of implementation here.

Answer 6

You could do the following:

DecimalFormatSymbols d = DecimalFormatSymbols.getInstance(Locale.getDefault());
input.setFilters(new InputFilter[] { new DecimalDigitsInputFilter(5, 2) });
input.setKeyListener(DigitsKeyListener.getInstance("0123456789" + d.getDecimalSeparator()));

And then you could use an input filter:

    public class DecimalDigitsInputFilter implements InputFilter {

Pattern mPattern;

public DecimalDigitsInputFilter(int digitsBeforeZero, int digitsAfterZero) {
    DecimalFormatSymbols d = new DecimalFormatSymbols(Locale.getDefault());
    String s = "\\" + d.getDecimalSeparator();
    mPattern = Pattern.compile("[0-9]{0," + (digitsBeforeZero - 1) + "}+((" + s + "[0-9]{0," + (digitsAfterZero - 1) + "})?)||(" + s + ")?");
}

@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {

    Matcher matcher = mPattern.matcher(dest);
    if (!matcher.matches())
        return "";
    return null;
}

}