TextWatcher watcher = new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s) {
            int a = Integer.parseInt(editPecaBoas.getText().toString());
            int b = Integer.parseInt(editPecaRuins.getText().toString());

            int i = a + b;

            String t = String.valueOf(i);

            textViewResult.setText(t);
        }
    };