在表单上，我有两个TextFormField，分别称为SKU和DESC。当我在SKU中放置某些内容时，我想在SQFLite数据库上对其进行验证，因此在SKU字段中放置了一个验证器。但是我不明白为什么会收到错误消息``无法将'Future'类型的值分配给'MasterItem'类型的变量。'，当我调用应从数据库中提取数据的函数时，可以有人解释我在做什么错？主要是如何验证SQFlite数据库中TextFormField的值？
非常感谢您！
import 'dart:core';
import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:aisscanning/data/database_helper.dart';
import 'package:aisscanning/data/inventoryitem.dart';
import 'package:aisscanning/data/masteritem.dart';
class InventoryScanning extends StatefulWidget {
InventoryScanning({Key key, this.title}) : super(key: key);
final String title;
@override
_InventoryScanningState createState() => new _InventoryScanningState();
}
class _InventoryScanningState extends State<InventoryScanning> {
static GlobalKey<FormState> _formKey = new GlobalKey<FormState>();
final TextEditingController teSku = TextEditingController();
final TextEditingController teDesc = TextEditingController();
bool lockLoc = true;
bool lockSubLoc = true;
bool lockQty = true;
bool lockPrice = true;
bool foundItem = false;
String itemDescription = '';
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text("Item Scanning"),
backgroundColor: Colors.black,
),
resizeToAvoidBottomPadding: false,
body: Padding(
padding: const EdgeInsets.only(top: 12.0),
child: new Form(
key: _formKey,
autovalidate: true,
child: new ListView(
// padding: const EdgeInsets.symmetric(horizontal: 16.0),
padding: new EdgeInsets.all(8.0),
itemExtent: 60.0,
children: <Widget>[
new Row(
// SKU
mainAxisSize: MainAxisSize.min,
children: <Widget>[
IconButton(
icon: const Icon(
Icons.input,
color: const Color(0xFF167F67),
size: 25.0,
),
onPressed: () {},
),
Expanded(
child: TextFormField(
controller: teSku,
validator: (value) {
if (value.isEmpty) {
return '';
} else {
MasterItem item;
item = checkSKU(); // <==== Error
teDesc.text = item.desc;
}
},
style: new TextStyle(
color: const Color(0xFF0f2638),
fontFamily: 'ProximaNova',
fontStyle: FontStyle.normal,
fontSize: 20.0,
),
decoration: new InputDecoration(
hintText: 'Enter SKU',
labelText: 'SKU',
contentPadding: new EdgeInsets.symmetric(
vertical: 15.0, horizontal: 10.0),
border: new OutlineInputBorder(
borderRadius: new BorderRadius.circular(25.0),
borderSide: new BorderSide(),
),
labelStyle: TextStyle(
color: Colors.black,
fontWeight: FontWeight.w600,
fontSize: 20.0,
),
),
),
),
IconButton(
icon: const Icon(
Icons.search,
color: const Color(0xFF167F67),
size: 25.0,
),
onPressed: () {},
),
],
),
new Row(
// Description
mainAxisSize: MainAxisSize.min,
children: <Widget>[
IconButton(
icon: const Icon(
Icons.text_fields,
color: const Color(0xFF167F67),
size: 25.0,
),
onPressed: () {},
),
Expanded(
child: TextFormField(
controller: teDesc,
style: new TextStyle(
color: const Color(0xFF0f2638),
fontFamily: 'ProximaNova',
fontStyle: FontStyle.normal,
fontSize: 20.0,
),
decoration: new InputDecoration(
labelText: 'Description',
contentPadding: new EdgeInsets.symmetric(
vertical: 15.0, horizontal: 10.0),
border: new OutlineInputBorder(
borderRadius: new BorderRadius.circular(25.0),
borderSide: new BorderSide(),
),
labelStyle: TextStyle(
color: Colors.black,
fontWeight: FontWeight.w600,
fontSize: 20.0,
),
),
),
),
]),
new Row(
// Buttons
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
new RaisedButton(
child: new Text("Save"),
onPressed: () {
addRecord();
},
shape: new RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(30.0)),
color: Colors.green,
elevation: 4.0,
),
new RaisedButton(
child: new Text("Cancel"),
onPressed: () {},
shape: new RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(30.0)),
color: Colors.red,
elevation: 4.0,
),
],
),
]),
),
),
);
}
Future addRecord() async {
var db = new DatabaseHelper();
String saveSku = teSku.text;
String saveDesc = teDesc.text;
print('Sku: $saveSku');
print('Desc: $saveDesc');
var inventoryItem = new InventoryItem(
saveSku, saveDesc);
await db.saveInventoryItem(inventoryItem);
}
Future<MasterItem> checkSKU() async {
var db = new DatabaseHelper();
MasterItem item;
String checkSku = teSku.text;
if (checkSku.trim().length > 0) {
item = await db.getMasterDesc(checkSku);
return item;
}
return item;
}
}