I was a developing a flutter app when I suddenly came across an error that I simply can't solve. I have a few variables declared in between the two classes of a stateful widget, and when I use setState() to update their values from within the <state> class, the app lags massively, and when more UI elements are added, the app will crash. I have never run into this issue before, and I have used the same principle to make it easier to access variables outside of the file.
This has happened on Flutter 3.6 beta, 3.3.8, and 3.0.0, meaning it's not a Flutter version issue. It doesn't matter whether the variables are null or not, it doesn't matter whether the variables are called outside of initState or after a delay. The app loads this page directly from main.dart, meaning it's also not because of any prior discrepancy.
I have reduced the error into a single file. Create a new project, copy the below code, and replace with the existing code in main.dart.
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const ErrorTest(),
);
}
}
class ErrorTest extends StatefulWidget {
const ErrorTest({super.key});
@override
State<ErrorTest> createState() => _ErrorTestState();
}
int? points;
String? firstName;
String? lastName;
String? email;
String? profilePicture;
int? timestamp;
String? date;
String? time;
String? institution;
String? address;
class _ErrorTestState extends State<ErrorTest> {
@override
void initState() {
setState(() {
firstName = "johny";
lastName = "johny";
email = "eeaeaa";
profilePicture = "a url";
timestamp = 123456789;
date = "2021-09-09";
time = "09:09:09";
institution = "123456789";
address = "123456789";
points = 123456789;
});
super.initState();
}
@override
Widget build(BuildContext context) {
return Text(
firstName.toString(),
);
}
}
Error log
Launching lib\main.dart on sdk gphone64 x86 64 in debug mode...
√ Built build\app\outputs\flutter-apk\app-debug.apk.
Connecting to VM Service at ws://127.0.0.1:54124/Kq8WOPDGOY8=/ws
I/scudo ( 5917): Stats: SizeClassAllocator64: 266M mapped (0M rss) in 322652 allocations; remains 269165
I/scudo ( 5917): 00 ( 64): mapped: 256K popped: 2171 pushed: 1950 inuse: 221 total: 728 rss: 0K releases: 0 last released: 0K region: 0x7dc6b6ce2000 (0x7dc6b6cd7000)
I/scudo ( 5917): 01 ( 32): mapped: 256K popped: 4498 pushed: 1950 inuse: 2548 total: 2548 rss: 0K releases: 0 last released: 0K region: 0x7dc6c6ce3000 (0x7dc6c6cd7000)
I/scudo ( 5917): 02 ( 48): mapped: 512K popped: 16055 pushed: 8268 inuse: 7787 total: 7800 rss: 0K releases: 0 last released: 0K region: 0x7dc6d6ce7000 (0x7dc6d6cd7000)
I/scudo ( 5917): 03 ( 64): mapped: 512K popped: 8412 pushed: 2132 inuse: 6280 total: 6332 rss: 0K releases: 0 last released: 0K region: 0x7dc6e6cdf000 (0x7dc6e6cd7000)
I/scudo ( 5917): 04 ( 80): mapped: 256K popped: 4771 pushed: 2444 inuse: 2327 total: 2444 rss: 0K releases: 0 last released: 0K region: 0x7dc6f6ce1000 (0x7dc6f6cd7000)
I/scudo ( 5917): 05 ( 96): mapped: 256K popped: 1079 pushed: 286 inuse: 793 total: 832 rss: 0K releases: 0 last released: 0K region: 0x7dc706ce7000 (0x7dc706cd7000)
I/scudo ( 5917): 06 ( 112): mapped: 256K popped: 1625 pushed: 1313 inuse: 312 total: 728 rss: 0K releases: 0 last released: 0K region: 0x7dc716ce2000 (0x7dc716cd7000)
I/scudo ( 5917): 07 ( 144): mapped: 256K popped: 1989 pushed: 650 inuse: 1339 total: 1352 rss: 0K releases: 0 last released: 0K region: 0x7dc726cdd000 (0x7dc726cd7000)
I/scudo ( 5917): 08 ( 176): mapped: 512K popped: 2711 pushed: 1443 inuse: 1268 total: 1853 rss: 0K releases: 0 last released: 0K region: 0x7dc736ce0000 (0x7dc736cd7000)
I/scudo ( 5917): 09 ( 192): mapped: 256K popped: 169 pushed: 13 inuse: 156 total: 156 rss: 0K releases: 0 last released: 0K region: 0x7dc746cdf000 (0x7dc746cd7000)
I/scudo ( 5917): 10 ( 224): mapped: 512K popped: 1365 pushed: 26 inuse: 1339 total: 1378 rss: 0K releases: 0 last released: 0K region: 0x7dc756ce6000 (0x7dc756cd7000)
I/scudo ( 5917): 11 ( 288): mapped: 256K popped: 650 pushed: 26 inuse: 624 total: 624 rss: 0K releases: 0 last released: 0K region: 0x7dc766ce2000 (0x7dc766cd7000)
I/scudo ( 5917): 12 ( 352): mapped: 256K popped: 1105 pushed: 949 inuse: 156 total: 728 rss: 0K releases: 6 last released: 124K region: 0x7dc776ce0000 (0x7dc776cd7000)
I/scudo ( 5917): 13 ( 448): mapped: 256K popped: 364 pushed: 91 inuse: 273 total: 312 rss: 0K releases: 1 last released: 4K region: 0x7dc786cdd000 (0x7dc786cd7000)
I/scudo ( 5917): 14 ( 592): mapped: 256K popped: 507 pushed: 247 inuse: 260 total: 416 rss: 0K releases: 4 last released: 8K region: 0x7dc796cd8000 (0x7dc796cd7000)
I/scudo ( 5917): 15 ( 800): mapped: 256K popped: 90 pushed: 0 inuse: 90 total: 120 rss: 0K releases: 0 last released: 0K region: 0x7dc7a6cde000 (0x7dc7a6cd7000)
I/scudo ( 5917): F 16 ( 1104): mapped: 261888K popped: 274165 pushed: 31255 inuse: 242910 total: 242910 rss: 0K releases: 31 last released: 3396K region: 0x7dc7b6cd9000 (0x7dc7b6cd7000)
I/scudo ( 5917): 17 ( 1648): mapped: 256K popped: 60 pushed: 4 inuse: 56 total: 64 rss: 0K releases: 0 last released: 0K region: 0x7dc7c6ce7000 (0x7dc7c6cd7000)
I/scudo ( 5917): 18 ( 2096): mapped: 256K popped: 78 pushed: 24 inuse: 54 total: 60 rss: 0K releases: 2 last released: 8K region: 0x7dc7d6ce1000 (0x7dc7d6cd7000)
I/scudo ( 5917): 19 ( 2576): mapped: 256K popped: 96 pushed: 0 inuse: 96 total: 96 rss: 0K releases: 0 last released: 0K region: 0x7dc7e6cde000 (0x7dc7e6cd7000)
I/scudo ( 5917): 20 ( 3120): mapped: 256K popped: 36 pushed: 2 inuse: 34 total: 40 rss: 0K releases: 1 last released: 8K region: 0x7dc7f6ce3000 (0x7dc7f6cd7000)
I/scudo ( 5917): 21 ( 4112): mapped: 512K popped: 224 pushed: 161 inuse: 63 total: 67 rss: 0K releases: 4 last released: 4K region: 0x7dc806cdf000 (0x7dc806cd7000)
I/scudo ( 5917): 22 ( 4624): mapped: 256K popped: 5 pushed: 2 inuse: 3 total: 8 rss: 0K releases: 2 last released: 20K region: 0x7dc816ce3000 (0x7dc816cd7000)
I/scudo ( 5917): 23 ( 7120): mapped: 512K popped: 99 pushed: 48 inuse: 51 total: 56 rss: 0K releases: 32 last released: 24K region: 0x7dc826ce3000 (0x7dc826cd7000)
I/scudo ( 5917): 24 ( 8720): mapped: 256K popped: 27 pushed: 0 inuse: 27 total: 28 rss: 0K releases: 0 last released: 0K region: 0x7dc836cdc000 (0x7dc836cd7000)
I/scudo ( 5917): 25 ( 11664): mapped: 256K popped: 22 pushed: 2 inuse: 20 total: 22 rss: 0K releases: 1 last released: 8K region: 0x7dc846cdd000 (0x7dc846cd7000)
I/scudo ( 5917): 26 ( 14224): mapped: 512K popped: 24 pushed: 2 inuse: 22 total: 26 rss: 0K releases: 1 last released: 12K region: 0x7dc856ce7000 (0x7dc856cd7000)
I/scudo ( 5917): 27 ( 16400): mapped: 256K popped: 16 pushed: 1 inuse: 15 total: 15 rss: 0K releases: 2 last released: 28K region: 0x7dc866cdc000 (0x7dc866cd7000)
I/scudo ( 5917): 28 ( 18448): mapped: 256K popped: 5 pushed: 0 inuse: 5 total: 8 rss: 0K releases: 0 last released: 0K region: 0x7dc876cde000 (0x7dc876cd7000)
I/scudo ( 5917): 29 ( 23056): mapped: 256K popped: 9 pushed: 1 inuse: 8 total: 8 rss: 0K releases: 3 last released: 84K region: 0x7dc886ce0000 (0x7dc886cd7000)
I/scudo ( 5917): 30 ( 29456): mapped: 512K popped: 13 pushed: 4 inuse: 9 total: 12 rss: 0K releases: 2 last released: 24K region: 0x7dc896ce4000 (0x7dc896cd7000)
I/scudo ( 5917): 31 ( 33296): mapped: 256K popped: 197 pushed: 192 inuse: 5 total: 7 rss: 0K releases: 5 last released: 28K region: 0x7dc8a6cdd000 (0x7dc8a6cd7000)
I/scudo ( 5917): 32 ( 65552): mapped: 1024K popped: 15 pushed: 1 inuse: 14 total: 15 rss: 0K releases: 1 last released: 60K region: 0x7dc8b6ce5000 (0x7dc8b6cd7000)
I/scudo ( 5917): Scudo OOM: The process has exhausted 256M for size class 1104.
E/SurfaceSyncer( 5917): Failed to find sync for id=0
W/Parcel ( 5917): Expecting binder but got null!
Reloaded 1 of 594 libraries in 597ms (compile: 55 ms, reload: 129 ms, reassemble: 155 ms).
D/EGL_emulation( 5917): app_time_stats: avg=8695.38ms min=53.84ms max=25809.32ms count=3
Reloaded 1 of 594 libraries in 2,177ms (compile: 18 ms, reload: 126 ms, reassemble: 1910 ms).
D/EGL_emulation( 5917): app_time_stats: avg=18633.52ms min=18633.52ms max=18633.52ms count=1
Lost connection to device.
Exited (sigterm)
CodePudding user response：
Why are you declaring your variables outside of all classes? You can declare them inside your state class with no problem.
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const ErrorTest(),
);
}
}
class ErrorTest extends StatefulWidget {
const ErrorTest({super.key});
@override
State<ErrorTest> createState() => _ErrorTestState();
}
class _ErrorTestState extends State<ErrorTest> {
int? points;
String? firstName;
String? lastName;
String? email;
String? profilePicture;
int? timestamp;
String? date;
String? time;
String? institution;
String? address;
@override
void initState() {
setState(() {
firstName = "johny";
lastName = "johny";
email = "eeaeaa";
profilePicture = "a url";
timestamp = 123456789;
date = "2021-09-09";
time = "09:09:09";
institution = "123456789";
address = "123456789";
points = 123456789;
});
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Text(
firstName.toString(),
),
),
);
}
}
CodePudding user response：
After a week of looking for a solution, I found that the issue is that I should have gone even a step lower and install Flutter 2.10.5. Reinstalling and resetting the path eliminates this issue. Will have to wait for flutter to fix this in future versions.