如何将带有浮动标签的文本窗体字段导入容器？
我试着让文本字段像这样，但我不居中我的标签，如果输入没有焦点。

我该怎么修？
我的代码。

class CustomInput extends StatefulWidget {
    final bool enabled;
    final bool readOnly;
    final double? width;
    final double? borderRadius;
    final bool autofocus;
    final int? maxLines;
    final int? maxLength;
    final bool obscureText;
    final String? hintText;
    final String? labelText;
    final String? errorText;
    final String? helperText;
    final String? counterText;
    final String? initialValue;
    final FocusNode? focusNode;
    final void Function()? onTap;
    final EdgeInsetsGeometry? margin;
    final TextInputType? keyboardType;
    final Function(String)? onChanged;
    final Widget? suffixIcon, prefixIcon;
    final TextInputAction? textInputAction;
    final TextEditingController? controller;
    final String? Function(String?)? validator;
    final Iterable<String>? autofillHints;
    final String? Function(String?)? onFieldSubmitted;
    final BoxConstraints? suffixIconConstraints;

    CustomInput({
        Key? key,
        this.controller,
        this.labelText,
        this.maxLength,
        this.focusNode,
        this.enabled = true,
        this.onChanged,
        this.textInputAction,
        this.keyboardType,
        this.onFieldSubmitted,
        this.validator,
        this.hintText,
        this.errorText,
        this.margin,
        this.obscureText = false,
        this.suffixIcon,
        this.autofillHints,
        this.helperText = '',
        this.prefixIcon,
        this.initialValue,
        this.onTap,
        this.readOnly = false,
        this.autofocus = false,
        this.maxLines = 1,
        this.suffixIconConstraints,
        this.width,
        this.counterText,
        this.borderRadius,
    }) : super(key: key);

    @override
        _CustomInputState createState() => _CustomInputState();
    }

class _CustomInputState extends State<CustomInput> {
    final _key = GlobalKey<FormFieldState<String>>();

    @override
    Widget build(BuildContext context) {
        OutlineInputBorder outlineInputBorder = OutlineInputBorder(
            gapPadding: 0,
            // borderSide: BorderSide(color: Colors.green),
            borderSide: BorderSide(color: Colors.transparent),
            borderRadius: BorderRadius.circular(widget.borderRadius ??),
        );

        return Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
                Container(
                width: widget.width,
                alignment: Alignment.centerLeft,
                // margin: widget.margin,
                padding: EdgeInsets.only(left: 16, right: 16),
                decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(widget.borderRadius ?? 8),
                    color: !widget.enabled
                        ? Theme.of(context).disabledColor
                        : Theme.of(context).scaffoldBackgroundColor,
                    border: Border.all(
                        width: 1,
                        color: !widget.enabled
                        ? Theme.of(context).disabledColor
                        : Theme.of(context).dividerColor,
                    ),
                ),
                child: TextFormField(
                    key: _key,
                    onTap: widget.onTap,
                    enabled: widget.enabled,
                    readOnly: widget.readOnly,
                    maxLines: widget.maxLines,
                    onChanged: widget.onChanged,
                    autofocus: widget.autofocus,
                    maxLength: widget.maxLength,
                    focusNode: widget.focusNode,
                    validator: widget.validator,
                    controller: widget.controller,
                    obscureText: widget.obscureText,
                    initialValue: widget.initialValue,
                    keyboardType: widget.keyboardType,
                    autofillHints: widget.autofillHints,
                    textInputAction: widget.textInputAction,
                    onFieldSubmitted: widget.onFieldSubmitted,
                    cursorColor: Theme.of(context).primaryColor,
                    textAlignVertical: TextAlignVertical.bottom,
                    decoration: InputDecoration(
                    isCollapsed: true,
                    // Theme config
                    // alignLabelWithHint: true,
                    labelStyle: TextStyle(
                    height: 3.8,
                    fontSize: 16.0,
                    backgroundColor: Colors.transparent,
                    // color: Theme.of(context).primaryColorLight,
                    ),
                    contentPadding: EdgeInsets.only(
                    top: 28,
                    left: 0,
                    right: 0,
                    bottom: 10,
                    ),
                    fillColor: Colors.transparent,
                    border: outlineInputBorder,
                    focusedBorder: outlineInputBorder,
                    enabledBorder: outlineInputBorder,
                    disabledBorder: outlineInputBorder,
                    errorBorder: OutlineInputBorder(
                    borderSide: BorderSide(color: Theme.of(context).errorColor),
                    borderRadius: BorderRadius.circular(widget.borderRadius ?? 8),
                    ),
                    errorStyle: TextStyle(
                    color: Theme.of(context).errorColor,
                    fontSize: 14,
                    height: 0.56,
                    ),

                    // Custom input config
                    filled: !widget.enabled,
                    hintText: widget.hintText,
                    labelText: widget.labelText,
                    errorText: widget.errorText,
                    // helperText: 'widget.helperText',
                    suffixIcon: widget.suffixIcon,
                    prefixIcon: widget.prefixIcon,
                    // helperStyle: TextStyle(height: 0.55),
                    helperStyle: TextStyle(height: 0),
                    counterText: widget.counterText ?? '',
                    suffixIconConstraints: widget.suffixIconConstraints,
                ),
            ),
            ),
            if (widget.helperText != null)
                Padding(
                    padding: EdgeInsets.only(left: 16, right: 16, top: 4),
                    child: Text(
                        widget.helperText!,
                        style: Theme.of(context).textTheme.caption,
                    ),
                ),
            ],
        );
    }
}

下一行不承载任何语义负载，它是leash，以便在发送帖子时不会出错。下一行不承载任何语义负载，它是leash，以便在发送帖子时不会出错。