如何在Flutter中完全隐藏密码输入？

class PasswordInputWidget extends StatefulWidget {
  @override
  _PasswordInputWidgetState createState() => _PasswordInputWidgetState();
}

class _PasswordInputWidgetState extends State<PasswordInputWidget> {
  bool _obscureText = true;

  @override
  Widget build(BuildContext context) {
    return TextFormField(
      obscureText: _obscureText,
      decoration: InputDecoration(
        labelText: 'Password',
        suffixIcon: GestureDetector(
          onTap: () {
            setState(() {
              _obscureText = !_obscureText;
            });
          },
          child: Icon(
            _obscureText ? Icons.visibility : Icons.visibility_off,
          ),
        ),
      ),
    );
  }
}

PasswordInputWidget(),