Android EditText控件自动转换大小写，光标位置不跳位

1et.addTextChangedListener(new TextWatcher()
2            {
3                int index = 0;
4                @Override
5                public void onTextChanged(CharSequence s, int start, int before, int count)
6                {
7                    // TODO Auto-generated method stub
8                }
9                
10                @Override
11                public void beforeTextChanged(CharSequence s, int start, int count,
12                        int after)
13                {
14                    // TODO Auto-generated method stub
15                }
16                
17                @Override
18                public void afterTextChanged(Editable s)
19                {
20                    // TODO Auto-generated method stub
21                    et.removeTextChangedListener(this);//解除文字改变事件
22                    index = et.getSelectionStart();//获取光标位置
23                    et.setText(s.toString().toUpperCase());转换
24                    et.setSelection(index);//重新设置光标位置
25                    et.addTextChangedListener(this);//重新绑定事件
26                    Log.i("mylog", s.toString());
27                }
28            });