限制EditText 输入的字节数

1、代码   

        name_tv = (EditText) findViewById( R.id.name_tv );
        
        name_tv.addTextChangedListener(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) {
                String string = s.toString().trim();

                //限定输入框最多输入18个字节
                int inputLength = string.length();
                int byteLength = string.getBytes().length;
                if (byteLength >= 18) {
                    name_tv.setFilters(new InputFilter[]{new InputFilter.LengthFilter(inputLength)});
                } else {
                    name_tv.setFilters(new InputFilter[]{new InputFilter.LengthFilter(18)});
                }
                name_tv.setSelection(name_tv.getText().toString().length());
            }
        });