当我滚动时,颤动的表格数据消失了

概述我有一个小部件,它有一个图像元素和表单元素的扩展列表视图,当我填写并滚动数据时它会在图像后面滚动时消失.我在调试时没有抛出任何错误,它发生在滚动窗口小部件顶部图像后面的任何字段上.有任何想法吗？ @override Widget build(BuildContext context) { var _children = <Widget>[ new Center( 我有一个小部件,它有一个图像元素和表单元素的扩展列表视图,当我填写并滚动数据时它会在图像后面滚动时消失.我在调试时没有抛出任何错误,它发生在滚动窗口小部件顶部图像后面的任何字段上.有任何想法吗？

@overrIDe  Widget build(BuildContext context) {    var _children = <Widget>[      new Center(        child: new Text(Widget.prov.fname + Widget.prov.lname,style: new TextStyle(FontSize: 20.0,FontWeight: FontWeight.bold),),new Center(          child: new Container(            padding: new EdgeInsets.only(                left: 125.0,right: 125.0,bottom: 50.0),child: new Image.network('http://174.138.61.246:8080/getimage/'+Widget.prov.pic.assetname),)      ),new Form(          key: _formKey,autovalIDate: _autovalIDate,onWillPop: _warnUserAboutInvalIDData,child: new Expanded(              child: new ListVIEw(                padding: const EdgeInsets.symmetric(horizontal: 16.0),children: <Widget>[                  new TextFormFIEld(                    decoration: const inputdecoration(                      icon: const Icon(Icons.person),hintText: 'First name?',labelText: 'First name *',onSaved: (String value) { referral.fname = value; },valIDator: _valIDatename,new TextFormFIEld(                    decoration: const inputdecoration(                      icon: const Icon(Icons.person),hintText: 'Last name?',labelText: 'Last name *',onSaved: (String value) { referral.lname = value; },new TextFormFIEld(                    decoration: const inputdecoration(                        icon: const Icon(Icons.phone),hintText: 'How to contact?',labelText: 'Phone Number *',prefixText: '+1'                    ),keyboardType: TextinputType.phone,onSaved: (String value) { referral.contact = value; },valIDator: _valIDatePhoneNumber,// TextinputFormatters are applIEd in sequence.                    inputFormatters: <TextinputFormatter> [                      WhiteListingTextinputFormatter.digitsOnly,// Fit the valIDating format.                      _phoneNumberFormatter,],new TextFormFIEld(                    decoration: const inputdecoration(                      hintText: 'Tell us about patIEnt',helperText: 'It does not have to be detailed yet',labelText: 'Referral Details',maxlines: 5,new _DateTimePicker(                    labelText: 'dob',selectedDate: _fromDate,selectDate: (DateTime date) {                      setState(() {                        referral.dob = date;                      });                    },new inputDecorator(                    decoration: const inputdecoration(                      labelText: 'Type of Appointment',hintText: 'Choose an Appointment Type',isEmpty: _typeAppt == null,child: new Dropdownbutton<String>(                      value: _typeAppt,isDense: true,onChanged: (String newValue) {                        setState(() {                          _typeAppt = newValue;                        });                      },items: _allTypeAppt.map((String value) {                        return new DropdownMenuItem<String>(                          value: value,child: new Text(value),);                      }).toList(),)          )      ),/*new Refreshindicator(        child: new ListVIEw.builder(          itemBuilder: _itemBuilder,itemCount: Listcount,onRefresh: _onRefresh,*/    ];    return new Scaffold(      appbar: new Appbar(Title: new Text("My ProvIDer")),body: new Column(        children: _children,);  }

解决方法 我认为问题是你没有保存放入TextFIElds的值(例如一个状态).
从您的代码我假设您使用ListVIEw.builder()来设置ListVIEw.如 documentation中所述,此方法仅呈现视野中的孩子.将子项滚动到视图外后,它将从ListVIEw中删除,只有在将其滚动到视图中后才会再次添加.由于删除了TextFIEld,因此也会删除该值.

要永久保存值,我建议使用TextFIElds并将输入保存到TextFIEld的onChanged()方法中,或者使用TextEditingController.

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