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

The above solutions do not take backspace into consideration so when you delete some numbers after typing, the format tends to mess up. Below code corrects this issue.

phoneNumberEditText.addTextChangedListener(new TextWatcher() {

        int beforeLength;

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            beforeLength = phoneNumberEditText.length();
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            int digits = phoneNumberEditText.getText().toString().length();
            if (beforeLength < digits && (digits == 3 || digits == 7)) {
                phoneNumberEditText.append("-");
            }
        }

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