目前正在構建我的第一個應用程式。從 Firebase 獲取資料。目的是希望讓更多人在肯尼亞接種 COVID 疫苗。
以下代碼說明：用戶使用搜索功能搜索特定縣，然后該縣的所有疫苗接種帖子將顯示相關資料。還有 2 個按鈕，yes 和 no。用戶可以投票讓其他用戶知道疫苗接種站是否仍在接種疫苗。此外，當按下按鈕時，它們應該被禁用。
我有一個 buttonPressed 串列，當呼叫時，根據可用疫苗接種帖子的數量添加 x 個“真實”。它們使用它們的索引鏈接在一起。
問題是添加按鈕后，出現“記憶體不足”錯誤。
沒有按鈕，它按預期運行。按鈕很重要，因為一些疫苗接種站仍在運行，而另一些則沒有。
問題：
1 - 我怎樣才能通過“記憶體不足”錯誤？
代碼：
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']
);
}
}
uj5u.com熱心網友回復：
buttonControls(numOfDrivers) {
print(numOfDrivers);
while (numOfDrivers > 0) {
buttonPressed.add(true);
}
print(buttonPressed);
}
numOfDrivers 參考不會隨時間改變，因為它是一個函式引數。每當您使用 numOfDrivers > 0 呼叫 buttonControls 時，您都會得到 OutOfMemory。
- 再問一個問題。這是一個普遍問題，與標題中的 OutOfMemory 陳述句無關。
轉載請註明出處，本文鏈接：https://www.uj5u.com/yidong/395305.html