限制EditText只能输入小数点后两位

设置EditText只能输入小数点后两位，在价格等有限制的输入时特别有效

    TextWatcher textWatcher = new TextWatcher() {
        @Override
        public void onTextChanged(CharSequence s, int start, int before,
                                  int count) {
            if (s.toString().contains(".")) {
                if (s.length() - 1 - s.toString().indexOf(".") > 2) {
                    s = s.toString().subSequence(0,
                            s.toString().indexOf(".") + 3);
                    priceEdit.setText(s);
                    priceEdit.setSelection(s.length());
                }
            }
            if (s.toString().trim().substring(0).equals(".")) {
                s = "0" + s;
                priceEdit.setText(s);
                priceEdit.setSelection(2);
            }
            if (s.toString().startsWith("0")
                    && s.toString().trim().length() > 1) {
                if (!s.toString().substring(1, 2).equals(".")) {
                    priceEdit.setText(s.subSequence(0, 1));
                    priceEdit.setSelection(1);
                    return;
                }
            }
        }
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                                      int after) {
        }
        @Override
        public void afterTextChanged(Editable s) {
        }
    };