Java 未处理的异常:NoSuchMethodError:方法';插入数据';被调用为空
我在试图获取和存储本地数据库中的位置时遇到此错误 这是我的主页Java 未处理的异常:NoSuchMethodError:方法';插入数据';被调用为空,java,android,flutter,dart,sqflite,Java,Android,Flutter,Dart,Sqflite,我在试图获取和存储本地数据库中的位置时遇到此错误 这是我的主页 import 'package:attendance_app/local_database/database_helper.dart'; import 'package:flutter/material.dart'; import 'package:geolocator/geolocator.dart'; import 'package:intl/intl.dart'; import 'package:toast/toast.dar
import 'package:attendance_app/local_database/database_helper.dart';
import 'package:flutter/material.dart';
import 'package:geolocator/geolocator.dart';
import 'package:intl/intl.dart';
import 'package:toast/toast.dart';
import 'package:attendance_app/local_database/database.dart';
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
bool _buttonEnabled = true;
Position _currentPosition;
String _formattedDate;
DataBaseHelper helper;
@override
void initState() {
// TODO: implement initState
super.initState();
_getCurrentLocation();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(
widget.title,
style: TextStyle(color: Colors.white),
),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Container(
height: 55.0,
width: 150.0,
color: Colors.lightGreen,
child: RaisedButton(
elevation: 0,
textColor: Colors.white,
splashColor: Colors.amber,
disabledColor: Colors.grey,
child: Text(
"Head start",
textScaleFactor: 1.6,
),
color: Colors.lightGreen,
onPressed: () async {
_getCurrentLocation();
_getDateTime();
_insertToDb(createDataBaseObj(
'IN',
_currentPosition.latitude.toString(),
_currentPosition.longitude.toString(),
_formattedDate));
Toast.show("$_currentPosition , $_formattedDate", context,
duration: Toast.LENGTH_LONG, gravity: Toast.BOTTOM);
},
),
),
SizedBox(
height: 20.0,
),
Container(
height: 55.0,
width: 150.0,
color: Colors.red[300],
child: RaisedButton(
elevation: 0,
textColor: Colors.white,
splashColor: Colors.amber,
disabledColor: Colors.grey,
child: Text(
"Check out",
textScaleFactor: 1.6,
),
color: Colors.red[300],
onPressed: () async {
_getCurrentLocation();
_getDateTime();
_insertToDb(createDataBaseObj(
'OUT',
_currentPosition.latitude.toString(),
_currentPosition.longitude.toString(),
_formattedDate));
Toast.show(
"$_currentPosition , $_formattedDate", context,
duration: Toast.LENGTH_LONG, gravity: Toast.BOTTOM);
},
)),
]),
),
bottomNavigationBar: Container(
height: 55.0,
color: _buttonEnabled ? Colors.green : Colors.grey,
child: RaisedButton(
elevation: 0,
textColor: Colors.white,
splashColor: Colors.amber,
disabledColor: Colors.grey,
child: Text(
"sync",
textScaleFactor: 1.6,
),
color: Colors.green,
onPressed: () async {},
)));
}
_getCurrentLocation() async {
final Geolocator geolocator = Geolocator()..forceAndroidLocationManager;
await geolocator
.getCurrentPosition(desiredAccuracy: LocationAccuracy.best)
.then((Position position) {
print(position);
setState(() {
_currentPosition = position;
});
}).catchError((e) {
print(e);
});
}
_getDateTime() {
DateTime now = DateTime.now();
String formattedDate = DateFormat('kk:mm:ss EEE d MMM').format(now);
setState(() {
_formattedDate = formattedDate;
});
}
DataBase createDataBaseObj(type, lat, long, time) {
DataBase result = DataBase(type, lat, long, time);
print('createDataBaseObj');
print(result.toMap());
return result;
}
void _insertToDb(DataBase dataBase) async {
var value = await helper.insertData(dataBase);
print(value);
}
void _delete(BuildContext context, DataBase dataBase) async {
await helper.deleteData(dataBase.id);
}
}
import'包:考勤应用程序/local\u数据库/database\u helper.dart';
进口“包装:颤振/材料.省道”;
导入“包:地理定位器/地理定位器.dart”;
导入“包:intl/intl.dart”;
导入“包装:toast/toast.dart”;
导入“package:Attention_app/local_database/database.dart”;
类MyHomePage扩展StatefulWidget{
MyHomePage({Key,this.title}):超级(Key:Key);
最后的字符串标题;
@凌驾
_MyHomePageState createState()=>\u MyHomePageState();
}
类_MyHomePageState扩展状态{
bool _buttonEnabled=真;
位置_当前位置;
字符串_formattedDate;
数据库助手;
@凌驾
void initState(){
//TODO:实现initState
super.initState();
_getCurrentLocation();
}
@凌驾
小部件构建(构建上下文){
返回脚手架(
appBar:appBar(
标题:正文(
widget.title,
样式:TextStyle(颜色:Colors.white),
),
),
正文:中(
子:列(
mainAxisAlignment:mainAxisAlignment.center,
儿童:[
容器(
身高:55.0,
宽度:150.0,
颜色:颜色。浅绿色,
孩子:升起按钮(
海拔:0,
textColor:Colors.white,
splashColor:Colors.amber,
禁用颜色:颜色。灰色,
子:文本(
“领先”,
textScaleFactor:1.6,
),
颜色:颜色。浅绿色,
onPressed:()异步{
_getCurrentLocation();
_getDateTime();
_insertToDb(createDataBaseObj(
"在",,
_currentPosition.latitude.toString(),
_currentPosition.longitude.toString(),
_形成日期);
Toast.show(“$\u currentPosition,$\u formattedDate”,上下文,
持续时间:Toast.LENGTH_LONG,重力:Toast.BOTTOM);
},
),
),
大小盒子(
身高:20.0,
),
容器(
身高:55.0,
宽度:150.0,
颜色:颜色。红色[300],
孩子:升起按钮(
海拔:0,
textColor:Colors.white,
splashColor:Colors.amber,
禁用颜色:颜色。灰色,
子:文本(
“退房”,
textScaleFactor:1.6,
),
颜色:颜色。红色[300],
onPressed:()异步{
_getCurrentLocation();
_getDateTime();
_insertToDb(createDataBaseObj(
“出去”,
_currentPosition.latitude.toString(),
_currentPosition.longitude.toString(),
_形成日期);
吐司,表演(
“$\u currentPosition,$\u formattedDate”,上下文,
持续时间:Toast.LENGTH_LONG,重力:Toast.BOTTOM);
},
)),
]),
),
底部导航栏:容器(
身高:55.0,
颜色:_按钮启用?颜色。绿色:颜色。灰色,
孩子:升起按钮(
海拔:0,
textColor:Colors.white,
splashColor:Colors.amber,
禁用颜色:颜色。灰色,
子:文本(
“同步”,
textScaleFactor:1.6,
),
颜色:颜色。绿色,
onPressed:()异步{},
)));
}
_getCurrentLocation()异步{
最终地理定位器Geolocator=Geolocator()…forceAndroidLocationManager;
等待地理定位器
.getCurrentPosition(所需精度:定位精度。最佳)
.然后((位置){
印刷(职位);
设置状态(){
_当前位置=位置;
});
}).catchError((e){
印刷品(e);
});
}
_getDateTime(){
DateTime now=DateTime.now();
字符串formattedDate=DateFormat('kk:mm:ss EEE d MMM')。格式(现在);
设置状态(){
_formattedDate=formattedDate;
});
}
数据库createDataBaseObj(类型、纬度、长度、时间){
数据库结果=数据库(类型、纬度、长度、时间);
打印('createDataBaseObj');
打印(result.toMap());
返回结果;
}
void\u insertToDb(数据库)异步{
var value=await helper.insertData(数据库);
印刷品(价值);
}
void\u delete(BuildContext上下文,数据库)异步{
等待helper.deleteData(dataBase.id);
}
}
这是数据库\u helper.dart文件
import 'package:sqflite/sqflite.dart';
import 'dart:async';
import 'dart:io';
import 'package:path_provider/path_provider.dart';
import 'database.dart';
class DataBaseHelper {
static DataBaseHelper _dataBaseHelper;
static Database _database;
String table = 'attendance';
String id = 'id';
String type = 'type';
String latitude = 'latitude';
String longitude = 'longitude';
String time = 'time_stamp';
DataBaseHelper._createInstance();
factory DataBaseHelper() {
if (_dataBaseHelper == null) {
_dataBaseHelper = DataBaseHelper._createInstance();
}
return _dataBaseHelper;
}
Future<Database> get database async{
if (_database == null){
_database = await initializeDatabase();
}
return _database;
}
Future<Database> initializeDatabase() async{
Directory directory = await getApplicationDocumentsDirectory();
String path = directory.path + 'attendance.db';
print(path);
var attendanceDb = await openDatabase(path,version: 1,onCreate: _createDb);
return attendanceDb;
}
// Create Table
void _createDb(Database db,int newVersion) async{
await db.execute('CREATE TABLE $table($id INTEGER PRIMARY KEY AUTOINCREMENT, $type TEXT,$latitude TEXT, $longitude TEXT, $time TEXT)');
}
// Fetch data from DB
Future<List<Map<String, String>>> getDatafromdb() async{
Database db = await this.database;
var result = await db.query(this.table);
return result;
}
// Insert data to DB
Future<int> insertData(DataBase dataBase) async{
var db = await this.database;
print('database');
print(db);
var result = await db.insert(this.table, dataBase.toMap());
return result;
}
// Delete data from DB
Future<int> deleteData(int Id) async{
var db = await this.database;
var result = await db.rawDelete('DELETE FROM $table WHERE $id = $Id');
return result;
}
}
import'包:sqflite/sqflite.dart';
导入“dart:async”;
导入“dart:io”;
导入“package:path_provider/path_provider.dart”;
导入“database.dart”;
类数据库助手{
静态DataBaseHelper\u DataBaseHelper;
静态数据库;
字符串表='Attention';
字符串id='id';
字符串类型='type';
字符串纬度='纬度';
字符串经度='经度';
字符串时间='time_stamp';
DataBaseHelper._createInstance();
FactoryDatabaseHelper(){
if(_dataBaseHelper==null){
_dataBaseHelper=dataBaseHelper.\u createInstance();
}
return\u dataBaseHelper;
}
未来获取数据库异步{
如果(_database==null){
_数据库=等待初始化数据库(
helper = DataBaseHelper();