实时监听EditText的输入长度

editText.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) {

                //长度发生变化，监听到输入的长度为 editText.getText().length()
                textView.setText(String.valueOf(editText.getText().length()) + "/10");
            }
        });