在Flutter中使用AlertDialog显示从数据库中选择的数据

如何解决在Flutter中使用AlertDialog显示从数据库中选择的数据

您好，我试图使用警报对话框来显示数据库中的特定数据或选定数据，但是我要显示的数据不会显示给alertDialog，因为我在数据库上使用地板的方式对任何建议或想法都非常有用非常感谢。

这是我的代码

Widget buildAboutDialog(BuildContext context,AddContactCallback _contactscreen,bool isEdit,ContactObject _contactObject)  {
      final databases = $FloorContactDatabase.databaseBuilder('Contacts.cb').build();
      if(contactObject != null) {
        this.contactObject = _contactObject;
        tfirstname.text = _contactObject.firstname;
        tlastname.text = _contactObject.lastname;
        tbirthday.text = _contactObject.birthday;
        tcontactnumber = _contactObject.contactnumber as TextEditingController ;
        tprofilepicture = _contactObject.profilepicture as File;
      } else {
        print('ERROR');
        print(tfirstname.value);
      }
      return new AlertDialog(
        title: new Text(isEdit ? 'Contact!' : 'Contact'),content: new SingleChildScrollView(
          child: new Column(
            mainAxisSize: MainAxisSize.max,crossAxisAlignment: CrossAxisAlignment.start,children: <Widget>[
              SizedBox(
              height: 10.0,),Align(
                alignment: Alignment.center,child: CircleAvatar(
                radius: 70,backgroundColor: Color(0xff476cfb),child: ClipOval(
                  child: new SizedBox(
                    width: 180.0,height: 180.0,child: (_image != null) ? Image.file(_image,// Image.file(File('${_contactsDao.profilepicture}'),fit: BoxFit.fill,) : Image.network(
                      "https://images.unsplash.com/photo-1502164980785-f8aa41d53611?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=500&q=60",getTextFieled("First Name",tfirstname),getTextFieled("Last Name",tlastname),getTextFieled("Birth day",tbirthday),getTextFieled("Contact No",tcontactnumber),],);
  }

这是函数和实例

    Widget getTextFieled(
      String inputData,TextEditingController inputTextController) {
      var btm = new Padding(
          padding: const EdgeInsets.all(5.0),child:  new  TextFormField(
            controller: inputTextController,decoration: new InputDecoration(
              hintText: inputData,);
      return btm;
 }

 Widget getAppButton (String buttonLabel,EdgeInsets margin){
    var btm = new Container(
      margin: margin,padding: EdgeInsets.all(8.0),alignment: FractionalOffset.center,decoration: new BoxDecoration(
        border: Border.all(color: const Color(0xFF28324E)),borderRadius: new BorderRadius.all(const Radius.circular(6.0)),child: new Text(
          buttonLabel,style: new TextStyle(
            color: const Color(0xFF28324E),fontSize: 20.0,fontWeight: FontWeight.w300,letterSpacing: 0.3,);
    return btm;
 }

 ContactObject getdata(bool isEdit) {
    return new ContactObject(
      firstname: tfirstname.text,lastname: tfirstname.text,birthday: tbirthday.text,contactnumber: int.parse(tcontactnumber.text),profilepicture: tprofilepicture.readAsStringSync(),);
 }

 onTap(bool isEdit,AddContactCallback addContactCallback,BuildContext context) {
    if(isEdit) {
      addContactCallback.updateContacts(getdata(isEdit));
      Navigator.of(context).pop();
      print('ANG PUMASOK');
      print(tfirstname);
    } else {
      Fluttertoast.showToast(
          msg: 'ERROR ERROR',toastLength: Toast.LENGTH_SHORT,timeInSecForIosWeb: 1,gravity: ToastGravity.BOTTOM
      );
    }
 }


}

abstract class AddContactCallback {
    void updateContacts(ContactObject contactObject);
}

这是我的想法的屏幕截图

解决方法

我认为在将值设置为TextFormField之后，需要将该值设置为TextEditingController。
返回小部件之前尝试一下，设置一个值；

Widget getTextFieled(
      String inputData,TextEditingController inputTextController) {
      var btm = new Padding(
          padding: const EdgeInsets.all(5.0),child:  new  TextFormField(
            controller: inputTextController,decoration: new InputDecoration(
              hintText: inputData,),);
      inputTextController.text = "Some Value Test";
      return btm;
 }

,

这种方法已经使用了很长时间，用于修改列表或其他项。

此代码仅是其工作方式的示例。

在基本窗口小部件中这样写：

class BaseWidget extends StatefulWidget {
  @override
  _BaseWidgetState createState() => new _BaseWidgetState();
}

class _BaseWidgetState extends State<BaseWidget> {
  @override
  void initState() {
    // get data from data base
    _getDataFromDataBase();
    super.initState();
  }

  var _listComingDataFromDataBase;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: _listComingDataFromDataBase == null
          ? Container(
              width: 50,height: 50,child: CircularProgressIndicator(),)
          : RefreshIndicator(
              onRefresh: () async {
                _getDataFromDataBase();
              },child: ListView.builder(
                itemBuilder: (context,index) {
                  return InkWell(
                    child: Container(
                      height: 100,onTap: () {
                      _buildAlertDialog(
                          context,_listComingDataFromDataBase[
                              index]); //open dialog and send selected object
                    },);
                },itemCount: _listComingDataFromDataBase.length,);
  }

  void _buildAlertDialog(context,selectedObject) {
    showDialog(
        context: context,child: AlertDialog(
          content: EditObjectWidget(selectedObject),)).then((isEdited) {
      if (isEdited) {
        // you can reload data from database
        _getDataFromDataBase();
      }
    });
  }

  void _getDataFromDataBase() {
    // database.getData.then((data){setState(){_listComingDataFromDataBase = data};});
  }
}

创建 EditObjectWidget ，如下所示：

class EditObjectWidget extends StatefulWidget {
  final selectedObject;

  EditObjectWidget(this.selectedObject);

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

class _EditObjectWidgetState extends State<EditObjectWidget> {
  final TextEditingController _firstNameController = TextEditingController();
  final TextEditingController _numberController = TextEditingController();

  @override
  void initState() {
    fillFields(widget.selectedObject);
    super.initState();
  }

  void fillFields(selectedObject) {
    _firstNameController.text = selectedObject.fistName ?? '';
    if (selectedObject.number != null)
      _numberController.text = selectedObject.number.toString();
  }

  @override
  void dispose() {
    _firstNameController.dispose();
    _numberController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        TextField(
          controller: _firstNameController,TextField(
          controller: _numberController,keyboardType: TextInputType.number,RaisedButton(
          onPressed: () {
            _updateObject();
          },child: Text('Submit'),)
      ],);
  }

  void _updateObject() {
    //update object in data base
    // database.updateObject({'number':_numberController.text,'first_name':_firstNameController.text});
    //if updateObject method return true,close dialog with true result,Otherwise false
    bool isEdited = true;
    if(!isEdited)
    {
      //show validation error,or another
    }
    else
    Navigator.pop(context,isEdited);
  }
}

我没有使用您的代码，这只是一个解释

希望此代码对您有帮助