Mask an EditText with Phone Number Format NaN like in PhoneNumberUtils

Question

I want to make user inputted phone number in an editText to dynamically change format every time the user inputs a number. That is, when user inputs up to 4 digits, like 714

Answer 1

This code allow you enter phone number with mask ### - ### - #### (without spaces) and also here is fixed the issue with deletion of phone digits:

editText.addTextChangedListener(new TextWatcher() {
            final static String DELIMITER = "-";
            String lastChar;

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                int digits = editText.getText().toString().length();
                if (digits > 1)
                    lastChar = editText.getText().toString().substring(digits-1);
            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                int digits = editText.getText().length();
                // prevent input dash by user
                if (digits > 0 && digits != 4 && digits != 8) {
                    CharSequence last = s.subSequence(digits - 1, digits);
                    if (last.toString().equals(DELIMITER))
                        editText.getText().delete(digits - 1, digits);
                }
                // inset and remove dash
                if (digits == 3 || digits == 7) {
                    if (!lastChar.equals(DELIMITER))
                        editText.append("-"); // insert a dash
                    else
                        editText.getText().delete(digits -1, digits); // delete last digit with a dash
                }
                dataModel.setPhone(s.toString());
            }

            @Override
            public void afterTextChanged(Editable s) {}
        });

Layout: