Creating separate class for listener

Question

What is the advantage of creating separate class for listener OR is there any?Which of the below code is more efficient and why?When should i create separate class?

Separate class for TextWatcher

mEditText.addTextChangedListener(mNumberWatcher);
TextWatcher mNumberWatcher = new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void afterTextChanged(Editable editable) {


        }
    };

No Separate class

mEditText.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void afterTextChanged(Editable editable) {

        }
    });

Answer 1

You should use separate class for listener when it needs to use same listener several times in our code, in many no. of classes.