当我删除我的TexFormField中的所有信息时，我遇到了问题。他似乎失去了焦点。我尝试了几种方法，但我没有看到它的工作原理
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return FocusScope(
      node: FocusScopeNode(),
      autofocus: false,
      canRequestFocus: true,
      child: TextFormField(
        focusNode: focusNode,
        textCapitalization: textCapitalization,
        onTapOutside: (event) => FocusScope.of(context).unfocus(),
        onChanged: (value) {
          onChanged?.call(value);
          if (value.isEmpty) {
            focusNode?.requestFocus();
          }
        },
        
        ),
      ),
    );
  }

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