Live editing of users input

Question

Is it possible to auto insert characters into an EditText as the user inputs data?

I.e. if the user is entering a long number such as <

Answer 1

This is what I used

private boolean mInEdit;

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
    if (!mInEdit) {
        mInEdit = true;
        String delimiter = " - ";
        //Remove chars from your delimiter first
        String digits = s.toString().replaceAll("[- ]", "")
                .replaceAll("\\d{4}", "$0" + delimiter);
        //Handle deletion
        int dLength = delimiter.length();
        if (before > count && digits.endsWith(delimiter.charAt(dLength - 1)) {
            digits = digits.substring(0, digits.length() - dLength);
        }
        mCardNumber.setText(digits);
        mCardNumber.setSelection(mCardNumber.length());
        mInEdit = false;
    }
}

Here you replace delimiter with what you want to separate digits.