如何在聚焦TextFormField时隐藏错误外观

TextEditingController _controller = TextEditingController();

TextFormField(
  controller: _controller,
  // 其他属性...
)

bool _isFocused = false;

TextFormField(
  controller: _controller,
  // 其他属性...
  onFocusChange: (hasFocus) {
    setState(() {
      _isFocused = hasFocus;
    });
  },
)

Stack(
  children: [
    TextFormField(
      controller: _controller,
      // 其他属性...
      onFocusChange: (hasFocus) {
        setState(() {
          _isFocused = hasFocus;
        });
      },
    ),
    Visibility(
      visible: !_isFocused,
      child: Container(
        // 错误外观的样式...
      ),
    ),
  ],
)