Question

我正在与这个DropDownItem框错误作斗争，一切似乎都有效，但在加载时会弹出黄色的界限。尝试了几件事，无法解决问题。我有Widget的代码。

@override
Widget build(BuildContext context) {
    var _children = <Widget>[
      !_createNew ? _referrerPractice() : _referrerCreate(),
    ];
    return new Scaffold(
        appBar: new AppBar(
          title: new Text(widget.title),
        ),
        body: new Column(
          mainAxisSize: MainAxisSize.max,
          children: _children,
        ));
  }

然后我将其用作其中一个功能。

Widget _referrerPractice() {
assert(!_createNew);
return new Form(
  key: _formKey2,
  child: new Expanded(
    child: new ListView(
      padding: const EdgeInsets.symmetric(horizontal: 16.0),
      children: <Widget>[
        new InputDecorator(
          decoration: const InputDecoration(
            labelText: 'Referrer Practice',
            hintText: 'Choose Referrer Practice or choose new',
          ),
          isEmpty: _referPractice == null,
          child: new DropdownButton<String>(
            value: _referPractice,
            isDense: true,
            onChanged: (String newValue) {
              setState(() {
                _referPractice = newValue;
              });
            },
            items: practicelist.map((Map value) {
              return new DropdownMenuItem<String>(
                value: value['id'].toString(),
                child: new Text(value['name']),
              );
            }).toList(),
          ),
        ),
        new RaisedButton(
            child: new Text('Start'), onPressed: _startReferrer),
      ],
    ),
  ),
);

}

它似乎在另一个页面上工作，我不使用函数来填充窗口小部件，只是一个常规的窗口小部件，但似乎它应该是相同的结构。

我缺少什么想法？这是一个DropDownButton，但它发生在结果页面上，其他函数也有DropDownButton。

EDIT ********** 这是工作代码

final List<String> _allTypeAppt = <String>['Elective OP', 'Hospital Transfer', 'Phone Consult'];

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 *',
                ),
                controller: _fnameController,

                onSaved: (String value) { referral.fname = value; },
                validator: _validateName,
              ),

              new TextFormField(
                decoration: const InputDecoration(
                  icon: const Icon(Icons.person),
                  hintText: 'Last Name?',
                  labelText: 'Last Name *',
                ),
                controller: _lnameController,
                onSaved: (String value) { referral.lname = value; },
                validator: _validateName,
              ),

              new _DateTimePicker(
                labelText: 'DOB',
                selectedDate: _fromDate,
                selectDate: (DateTime date) {
                  setState(() {
                    _fromDate = date;
                  });
                },
              ),

              new TextFormField(
                decoration: const InputDecoration(
                    icon: const Icon(Icons.phone),
                    hintText: 'How to contact?',
                    labelText: 'Phone Number *',
                ),
                controller: _phoneController,
                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(
                  icon: const Icon(Icons.phone),
                  hintText: 'Alt contact?',
                  labelText: 'Alt Phone Number *',
                ),
                controller: _altPhoneController,
                keyboardType: TextInputType.phone,
                onSaved: (String value) { referral.altcontact = value; },
                validator: _validatePhoneNumber,
                // TextInputFormatters are applied in sequence.
                /*inputFormatters: <TextInputFormatter> [
                  WhitelistingTextInputFormatter.digitsOnly,
                  // Fit the validating format.
                  _phoneNumberFormatter,
                ],*/
              ),

              new TextFormField(
                decoration: const InputDecoration(
                  icon: const Icon(Icons.email),
                  hintText: 'Patien Email?',
                  labelText: 'Patient Email *',
                ),
                controller: _emailController,
                onSaved: (String value) { referral.altcontact = 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',
                ),
                controller: _detailsController,
                maxLines: 5,
              ),

              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 RaisedButton(
                child: new Text('Submit Referral'),
                onPressed: _submitData,
              ),

            ],

          )
      )
  ),

Answer 1

我能够重现你的问题，我不知道你为什么要用这种方式构建布局。您正在将DropDownButton作为child的{{1}}属性，这很好。但是，由于InputDecorator溢出DropDownMenuItem，因此会抛出此错误。换句话说，您不仅在InputDecorator中包含DopDownButton，而且您的InputDecorator也试图包含在同一空间中。因此，Flutter对如何将items列表放在items提供的空间内感到困惑。

我真的很困惑你正在尝试构建什么样的布局，为什么需要InputDecorator和Form？

可能会为您的设计选择提供一些背景信息，以便我们能够提供更好的帮助。

我使用InputDecorator和Row小部件创建了一个更简单的布局，它可能会有所帮助。

TextField

在布局期间，Flutter RenderIndexedStack对象被赋予无限大小

1 个答案: