EditText怎么控制不让输入0开头的数字？

EditText.addTextChangeListener(mTextWatcher);
//在一开始声明TextWatcher，在afterTextChange内操作
private TextWatcher mTextWatcher=new TextWatcher() {

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
// TODO Auto-generated method stub

}

@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
// TODO Auto-generated method stub

}

@Override
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
String text = s.toString(); 
 int len = s.toString().length(); 
 if (len == 1 && text.equals("0")) { 
 s.clear(); 
}
}
};

给EditView添加TextWatcher@Overridepublic void afterTextChanged(Editable s){ String text = s.toString(); int len = s.toString().length(); if (len == 1 && text.equles("0")) { s.clear(); }}