Flutter 项目出现内存不足错误
Flutter project giving Out of Memory error
目前正在构建我的第一个应用程序。从 Firebase 获取数据。目的是希望让更多人在肯尼亚接种 COVID 疫苗。
下面代码的解释：用户使用搜索功能搜索特定的县，然后该县的所有疫苗接种post都会出现与相关数据。还有 2 个按钮，是和否。用户可以投票让其他用户知道疫苗接种 post 是否仍在接种疫苗。此外，当按下按钮时，它们应该被禁用。
我有一个 buttonPressed 列表，当被调用时，会添加 x 个“true”，具体取决于可用的疫苗接种数量 post。他们使用他们的索引链接在一起。
问题是在添加按钮后，出现“内存不足”错误。
没有按钮，它会按预期运行。按钮很重要，因为一些疫苗接种 post 仍在运行，而另一些则没有。
问题：
1 - 如何解决“内存不足”错误？
代码：
import 'package:colour/colour.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:google_fonts/google_fonts.dart';
import 'dart:async';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
// import 'package:shared_preferences/shared_preferences.dart';
class VaccineCenterList extends StatefulWidget {
const VaccineCenterList({key}) : super(key: key);
static const String idScreen = "VaccineCenterList";
@override
_VaccineCenterListState createState() => _VaccineCenterListState();
}
class _VaccineCenterListState extends State<VaccineCenterList> {
List<bool> buttonPressed = [];
buttonControls(numOfDrivers) {
print(numOfDrivers);
while (numOfDrivers > 0) {
buttonPressed.add(true);
}
print(buttonPressed);
}
@override
void initState() {
super.initState();
print("I'm in the vaccine list search screen");
}
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.grey[100],
appBar: AppBar(
backgroundColor: Colors.grey[100],
centerTitle: true,
elevation: 0,
iconTheme: const IconThemeData(
color: Colors.black,
),
title: Text(
"Pamoja",
style: GoogleFonts.lexendMega(
fontWeight: FontWeight.bold,
color: Colors.black,
fontSize: 35,
),
),
),
body: GestureDetector(
onTap: () {
FocusScope.of(context).requestFocus(FocusNode());
},
child: SingleChildScrollView(
child: Column(
children: [
Container(
// textfield
padding: const EdgeInsets.all(8.0),
child: TextField(
controller: hospitalCountyEditingController,
keyboardType: TextInputType.text,
textCapitalization: TextCapitalization.words,
decoration: InputDecoration(
border: const OutlineInputBorder(
borderSide: BorderSide(
color: Colors.black,
style: BorderStyle.solid,
width: 1,
),
),
labelText: "Search County",
labelStyle: const TextStyle(
fontSize: 14.0,
color: Colors.blueGrey,
),
hintStyle: GoogleFonts.lexendMega(
color: Colors.grey,
fontSize: 10,
),
),
style: GoogleFonts.lexendMega(
fontSize: 14,
color: Colors.black,
),
),
),
ElevatedButton(
// search button
onPressed: () {
setState(() {
FocusScope.of(context).requestFocus(
FocusNode(),
);
driverList.clear();
if (hospitalCountyEditingController.text == "" ||
hospitalCountyEditingController.text == " ") {
isTrueOrFalse = "False";
} else {
isTrueOrFalse = "True";
}
});
getHospitalDetails();
},
child: Text(
"Search",
style: GoogleFonts.lexendMega(
fontWeight: FontWeight.bold,
),
),
),
SingleChildScrollView(
child: Column(
children: [
SizedBox(
height: MediaQuery.of(context).size.height,
// height: 50,
// color: Colors.black,
child: Padding(
padding: const EdgeInsets.only(
right: 12.0,
left: 12.0,
bottom: 12.0,
),
child: driverList.isEmpty
? Center(
// child: CircularProgressIndicator(),
child: (isTrueOrFalse == "True")
? const CircularProgressIndicator()
: Column(
mainAxisAlignment:
MainAxisAlignment.center,
children: [
Padding(
padding: const EdgeInsets.all(8.0),
child: Text(
"Search for one of the counties below",
style:
GoogleFonts.lexendMega()),
),
Text(
"Nairobi, Baringo, Busia, Bomet, Bungoma, Elgeyo Marakwet, Embu, Garissa, Homa Bay, Isiolo, Kajiado, Kakamega, Kericho, Kiambu, Kilifi, Kirinyaga, Kisii, Kisumu, Kitui, Kwale, Laikipia, Lamu, Machakos, Makueni, Mandera, Marsabit, Meru, Migori, Mombasa, Muranga, Nakuru, Nandi, Narok, Nyamira, Nyandarua, Nyeri, Samburu, Siaya County, Taita Taveta, Tana River County, Tharaka Nithi, Trans Nzoia, Turkana, Uasin Gishu, Vihiga, Wajir, West Pokot",
textAlign: TextAlign.center,
style: GoogleFonts.lexendMega(
fontWeight: FontWeight.bold,
),
),
],
),
)
: ListView.builder(
itemCount: driverList.length,
itemBuilder: (context, index) {
buttonControls(driverList.length);
final Hospitals hospitals = driverList[index];
final String hospitalLocaiton =
hospitals.location;
final String hospitalPhone = hospitals.phone;
final String hospitalName = hospitals.name;
positiveCount = hospitals.positiveCount;
negativeCount = hospitals.negativeCount;
final int setpercentage =
calculatePositivePercentage(
positiveCount, negativeCount);
return Padding(
padding: const EdgeInsets.all(8.0),
child: Card(
elevation: 0,
child: ExpansionTile(
title: Text(
hospitalName.toUpperCase(),
style: GoogleFonts.lexendMega(),
textAlign: TextAlign.center,
),
children: [
Column(
children: [
Container(
child: (hospitalPhone
.isNotEmpty)
? ElevatedButton(
onPressed: () {
Clipboard.setData(
ClipboardData(
text:
hospitalPhone,
),
);
ScaffoldMessenger.of(
context)
.showSnackBar(
const SnackBar(
backgroundColor:
Colors.green,
content: Text(
"Number Copied",
textAlign:
TextAlign
.center,
),
),
);
},
child: Text(
hospitalPhone,
textAlign:
TextAlign.center,
style: GoogleFonts
.lexendMega(
fontSize: 13),
),
style: ElevatedButton
.styleFrom(
elevation: 0,
),
)
: const Text(""),
),
const SizedBox(
height: 5,
),
hospitalLocaiton.isNotEmpty
? Container(
padding:
const EdgeInsets.all(
8),
decoration: BoxDecoration(
border: Border.all(
color: Colors.black,
),
borderRadius:
BorderRadius
.circular(10),
),
child: Text(
hospitalLocaiton,
textAlign:
TextAlign.center,
style: GoogleFonts
.lexendMega(
fontSize: 12,
),
),
)
: Text(
hospitalLocaiton,
textAlign:
TextAlign.center,
style: GoogleFonts
.lexendMega(
fontSize: 12,
),
),
const SizedBox(
height: 10,
),
Text(
"$setpercentage% (percent) of voters say this hospital administer vaccines.",
textAlign: TextAlign.center,
style: GoogleFonts.lexendMega(
fontWeight: FontWeight.bold,
fontSize: 12,
color: Colors.deepPurple[400],
),
),
const SizedBox(
height: 10,
),
const Divider(
// thickness: 1,
indent: 20,
endIndent: 20,
color: Colors.black87,
),
const SizedBox(
height: 10,
),
Text(
"Does this Hospital administer Vaccines?\n(To help the public, please vote only if you know.)",
textAlign: TextAlign.center,
style: GoogleFonts.lexendMega(
fontSize: 12,
fontWeight: FontWeight.bold,
),
),
// Container(
// child: (positiveCount == 0)
// ? Text("Votes: $positiveCount")
// : Text("Votes: " +
// positiveCount.toString()),
// ),
Column(
children: [
Row(
mainAxisAlignment:
MainAxisAlignment
.spaceEvenly,
children: [
ElevatedButton(
onPressed:
buttonPressed[index]
? () {
positiveIncrement(
hospitalName,
index);
ScaffoldMessenger.of(
context)
.showSnackBar(
const SnackBar(
backgroundColor:
Colors.redAccent,
content:
Text(
"Voted",
textAlign:
TextAlign.center,
),
),
);
}
: null,
child: Text(
"Yes",
style: GoogleFonts
.lexendMega(),
),
style: ElevatedButton
.styleFrom(
primary:
Colour("#87D68D"),
),
),
ElevatedButton(
onPressed:
buttonPressed[index]
? () {
negativeIncrement(
hospitalName,
index);
ScaffoldMessenger.of(
context)
.showSnackBar(
const SnackBar(
backgroundColor:
Colors.redAccent,
content:
Text(
"Voted",
textAlign:
TextAlign.center,
),
),
);
}
: null,
child: Text(
"No",
style: GoogleFonts
.lexendMega(),
),
style: ElevatedButton
.styleFrom(
primary:
Colour("#E3655B"),
),
),
],
),
// const SizedBox(
// height: 10,
// ),
// Text(
// "Total No. of Votes: ",
// style:
// GoogleFonts.lexendMega(
// fontSize: 12),
// ),
const SizedBox(
height: 10,
),
Text(
"1 - To vote, tap once\n2 - To Undo vote, tap and hold",
style:
GoogleFonts.lexendMega(
fontSize: 12,
),
textAlign: TextAlign.start,
),
const SizedBox(
height: 10,
),
],
),
],
),
],
),
),
);
},
),
),
),
// SizedBox(height: 40),
],
),
),
],
),
),
),
);
}
}
class Hospitals {
final String name;
final String phone;
final String location;
// final String county;
final int positiveCount;
final int negativeCount;
// final int intPercentage;
// final int totalVotes;
Hospitals({
required this.name,
required this.phone,
required this.location,
// required this.county,
required this.positiveCount,
required this.negativeCount,
// required this.intPercentage,
// required this.totalVotes,
});
static Hospitals fromJson(Map<String, dynamic> json) {
return Hospitals(
name: json['HospitalName'],
phone: json['HospitalPhone'],
// county: json['county'],
location: json['HospitalAddres'],
positiveCount: json['poitiveCount'],
negativeCount: json['negativeCount'],
// intPercentage: json['intPercentage'],
// totalVotes: json['totalVotes']
);
}
}
buttonControls(numOfDrivers) {
print(numOfDrivers);
while (numOfDrivers > 0) {
buttonPressed.add(true);
}
print(buttonPressed);
}
numOfDrivers 引用不会随时间改变，因为它是一个函数参数。每当您使用 numOfDrivers > 0 调用 buttonControls 时，您都会得到 OutOfMemory。
- 再问一个问题。一般问题，与标题中的OutOfMemory语句无关。
目前正在构建我的第一个应用程序。从 Firebase 获取数据。目的是希望让更多人在肯尼亚接种 COVID 疫苗。
下面代码的解释：用户使用搜索功能搜索特定的县，然后该县的所有疫苗接种post都会出现与相关数据。还有 2 个按钮，是和否。用户可以投票让其他用户知道疫苗接种 post 是否仍在接种疫苗。此外，当按下按钮时，它们应该被禁用。
我有一个 buttonPressed 列表，当被调用时，会添加 x 个“true”，具体取决于可用的疫苗接种数量 post。他们使用他们的索引链接在一起。
问题是在添加按钮后，出现“内存不足”错误。
没有按钮，它会按预期运行。按钮很重要，因为一些疫苗接种 post 仍在运行，而另一些则没有。
问题：
1 - 如何解决“内存不足”错误？
代码：
import 'package:colour/colour.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:google_fonts/google_fonts.dart';
import 'dart:async';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
// import 'package:shared_preferences/shared_preferences.dart';
class VaccineCenterList extends StatefulWidget {
const VaccineCenterList({key}) : super(key: key);
static const String idScreen = "VaccineCenterList";
@override
_VaccineCenterListState createState() => _VaccineCenterListState();
}
class _VaccineCenterListState extends State<VaccineCenterList> {
List<bool> buttonPressed = [];
buttonControls(numOfDrivers) {
print(numOfDrivers);
while (numOfDrivers > 0) {
buttonPressed.add(true);
}
print(buttonPressed);
}
@override
void initState() {
super.initState();
print("I'm in the vaccine list search screen");
}
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.grey[100],
appBar: AppBar(
backgroundColor: Colors.grey[100],
centerTitle: true,
elevation: 0,
iconTheme: const IconThemeData(
color: Colors.black,
),
title: Text(
"Pamoja",
style: GoogleFonts.lexendMega(
fontWeight: FontWeight.bold,
color: Colors.black,
fontSize: 35,
),
),
),
body: GestureDetector(
onTap: () {
FocusScope.of(context).requestFocus(FocusNode());
},
child: SingleChildScrollView(
child: Column(
children: [
Container(
// textfield
padding: const EdgeInsets.all(8.0),
child: TextField(
controller: hospitalCountyEditingController,
keyboardType: TextInputType.text,
textCapitalization: TextCapitalization.words,
decoration: InputDecoration(
border: const OutlineInputBorder(
borderSide: BorderSide(
color: Colors.black,
style: BorderStyle.solid,
width: 1,
),
),
labelText: "Search County",
labelStyle: const TextStyle(
fontSize: 14.0,
color: Colors.blueGrey,
),
hintStyle: GoogleFonts.lexendMega(
color: Colors.grey,
fontSize: 10,
),
),
style: GoogleFonts.lexendMega(
fontSize: 14,
color: Colors.black,
),
),
),
ElevatedButton(
// search button
onPressed: () {
setState(() {
FocusScope.of(context).requestFocus(
FocusNode(),
);
driverList.clear();
if (hospitalCountyEditingController.text == "" ||
hospitalCountyEditingController.text == " ") {
isTrueOrFalse = "False";
} else {
isTrueOrFalse = "True";
}
});
getHospitalDetails();
},
child: Text(
"Search",
style: GoogleFonts.lexendMega(
fontWeight: FontWeight.bold,
),
),
),
SingleChildScrollView(
child: Column(
children: [
SizedBox(
height: MediaQuery.of(context).size.height,
// height: 50,
// color: Colors.black,
child: Padding(
padding: const EdgeInsets.only(
right: 12.0,
left: 12.0,
bottom: 12.0,
),
child: driverList.isEmpty
? Center(
// child: CircularProgressIndicator(),
child: (isTrueOrFalse == "True")
? const CircularProgressIndicator()
: Column(
mainAxisAlignment:
MainAxisAlignment.center,
children: [
Padding(
padding: const EdgeInsets.all(8.0),
child: Text(
"Search for one of the counties below",
style:
GoogleFonts.lexendMega()),
),
Text(
"Nairobi, Baringo, Busia, Bomet, Bungoma, Elgeyo Marakwet, Embu, Garissa, Homa Bay, Isiolo, Kajiado, Kakamega, Kericho, Kiambu, Kilifi, Kirinyaga, Kisii, Kisumu, Kitui, Kwale, Laikipia, Lamu, Machakos, Makueni, Mandera, Marsabit, Meru, Migori, Mombasa, Muranga, Nakuru, Nandi, Narok, Nyamira, Nyandarua, Nyeri, Samburu, Siaya County, Taita Taveta, Tana River County, Tharaka Nithi, Trans Nzoia, Turkana, Uasin Gishu, Vihiga, Wajir, West Pokot",
textAlign: TextAlign.center,
style: GoogleFonts.lexendMega(
fontWeight: FontWeight.bold,
),
),
],
),
)
: ListView.builder(
itemCount: driverList.length,
itemBuilder: (context, index) {
buttonControls(driverList.length);
final Hospitals hospitals = driverList[index];
final String hospitalLocaiton =
hospitals.location;
final String hospitalPhone = hospitals.phone;
final String hospitalName = hospitals.name;
positiveCount = hospitals.positiveCount;
negativeCount = hospitals.negativeCount;
final int setpercentage =
calculatePositivePercentage(
positiveCount, negativeCount);
return Padding(
padding: const EdgeInsets.all(8.0),
child: Card(
elevation: 0,
child: ExpansionTile(
title: Text(
hospitalName.toUpperCase(),
style: GoogleFonts.lexendMega(),
textAlign: TextAlign.center,
),
children: [
Column(
children: [
Container(
child: (hospitalPhone
.isNotEmpty)
? ElevatedButton(
onPressed: () {
Clipboard.setData(
ClipboardData(
text:
hospitalPhone,
),
);
ScaffoldMessenger.of(
context)
.showSnackBar(
const SnackBar(
backgroundColor:
Colors.green,
content: Text(
"Number Copied",
textAlign:
TextAlign
.center,
),
),
);
},
child: Text(
hospitalPhone,
textAlign:
TextAlign.center,
style: GoogleFonts
.lexendMega(
fontSize: 13),
),
style: ElevatedButton
.styleFrom(
elevation: 0,
),
)
: const Text(""),
),
const SizedBox(
height: 5,
),
hospitalLocaiton.isNotEmpty
? Container(
padding:
const EdgeInsets.all(
8),
decoration: BoxDecoration(
border: Border.all(
color: Colors.black,
),
borderRadius:
BorderRadius
.circular(10),
),
child: Text(
hospitalLocaiton,
textAlign:
TextAlign.center,
style: GoogleFonts
.lexendMega(
fontSize: 12,
),
),
)
: Text(
hospitalLocaiton,
textAlign:
TextAlign.center,
style: GoogleFonts
.lexendMega(
fontSize: 12,
),
),
const SizedBox(
height: 10,
),
Text(
"$setpercentage% (percent) of voters say this hospital administer vaccines.",
textAlign: TextAlign.center,
style: GoogleFonts.lexendMega(
fontWeight: FontWeight.bold,
fontSize: 12,
color: Colors.deepPurple[400],
),
),
const SizedBox(
height: 10,
),
const Divider(
// thickness: 1,
indent: 20,
endIndent: 20,
color: Colors.black87,
),
const SizedBox(
height: 10,
),
Text(
"Does this Hospital administer Vaccines?\n(To help the public, please vote only if you know.)",
textAlign: TextAlign.center,
style: GoogleFonts.lexendMega(
fontSize: 12,
fontWeight: FontWeight.bold,
),
),
// Container(
// child: (positiveCount == 0)
// ? Text("Votes: $positiveCount")
// : Text("Votes: " +
// positiveCount.toString()),
// ),
Column(
children: [
Row(
mainAxisAlignment:
MainAxisAlignment
.spaceEvenly,
children: [
ElevatedButton(
onPressed:
buttonPressed[index]
? () {
positiveIncrement(
hospitalName,
index);
ScaffoldMessenger.of(
context)
.showSnackBar(
const SnackBar(
backgroundColor:
Colors.redAccent,
content:
Text(
"Voted",
textAlign:
TextAlign.center,
),
),
);
}
: null,
child: Text(
"Yes",
style: GoogleFonts
.lexendMega(),
),
style: ElevatedButton
.styleFrom(
primary:
Colour("#87D68D"),
),
),
ElevatedButton(
onPressed:
buttonPressed[index]
? () {
negativeIncrement(
hospitalName,
index);
ScaffoldMessenger.of(
context)
.showSnackBar(
const SnackBar(
backgroundColor:
Colors.redAccent,
content:
Text(
"Voted",
textAlign:
TextAlign.center,
),
),
);
}
: null,
child: Text(
"No",
style: GoogleFonts
.lexendMega(),
),
style: ElevatedButton
.styleFrom(
primary:
Colour("#E3655B"),
),
),
],
),
// const SizedBox(
// height: 10,
// ),
// Text(
// "Total No. of Votes: ",
// style:
// GoogleFonts.lexendMega(
// fontSize: 12),
// ),
const SizedBox(
height: 10,
),
Text(
"1 - To vote, tap once\n2 - To Undo vote, tap and hold",
style:
GoogleFonts.lexendMega(
fontSize: 12,
),
textAlign: TextAlign.start,
),
const SizedBox(
height: 10,
),
],
),
],
),
],
),
),
);
},
),
),
),
// SizedBox(height: 40),
],
),
),
],
),
),
),
);
}
}
class Hospitals {
final String name;
final String phone;
final String location;
// final String county;
final int positiveCount;
final int negativeCount;
// final int intPercentage;
// final int totalVotes;
Hospitals({
required this.name,
required this.phone,
required this.location,
// required this.county,
required this.positiveCount,
required this.negativeCount,
// required this.intPercentage,
// required this.totalVotes,
});
static Hospitals fromJson(Map<String, dynamic> json) {
return Hospitals(
name: json['HospitalName'],
phone: json['HospitalPhone'],
// county: json['county'],
location: json['HospitalAddres'],
positiveCount: json['poitiveCount'],
negativeCount: json['negativeCount'],
// intPercentage: json['intPercentage'],
// totalVotes: json['totalVotes']
);
}
}
buttonControls(numOfDrivers) {
print(numOfDrivers);
while (numOfDrivers > 0) {
buttonPressed.add(true);
}
print(buttonPressed);
}
numOfDrivers 引用不会随时间改变，因为它是一个函数参数。每当您使用 numOfDrivers > 0 调用 buttonControls 时，您都会得到 OutOfMemory。
- 再问一个问题。一般问题，与标题中的OutOfMemory语句无关。