EditText输入电话号码自带空格

形如：183 2185 9453

类源码：

 public static int mobileChanged(CharSequence s, int start, int before, int count, EditText editText,int changdu) {
        StringBuilder sb = new StringBuilder();
        int index=s.length();
        if(changdu

activity里面调用：

private TextWatcher numberWatcher =new TextWatcher() {
        private int changchu;
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        }
        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
           changchu= ForNumber.mobileChanged(s,start,before,count,et_number,changchu);
            
        }
        @Override
        public void afterTextChanged(Editable s) {

        }
    };

onTextChanged参数解释及实现EditText字数监听