Flutter - Will BLoC stream instances cause memory leak when a widget is closed?
There are some scenarios where screens with their respective BLoCs are frequently created and closed. So I'm somewhat concerned about memory safety of the Streams instances created in this process, because it doesn't seem they are disposed somewhere or whether they are GC-ed. This clearly depends on the specific implementation of DART libraries and flutter. So if you know about their behavior, please let me know.
These are some scenarios I have encountered.
- Multi-tab browser-like application.
- Navigation through screens. (But it's not that harmful.)
- showDialog() senarios when there are BLoCs inside the dialog. This is a far more common senario. There could be a lot of dialog popping up frequently in an app.
I wonder if it is necessary to override dispose() function and explicitly close all streams in BLoCProvider. It seems existing tutorials didn't mention it.
dart 
flutter rxdart asked Nov 20 '18 at 10:54
First_Strike
1128
add a comment |
There are some scenarios where screens with their respective BLoCs are frequently created and closed. So I'm somewhat concerned about memory safety of the Streams instances created in this process, because it doesn't seem they are disposed somewhere or whether they are GC-ed. This clearly depends on the specific implementation of DART libraries and flutter. So if you know about their behavior, please let me know.
These are some scenarios I have encountered.
- Multi-tab browser-like application.
- Navigation through screens. (But it's not that harmful.)
- showDialog() senarios when there are BLoCs inside the dialog. This is a far more common senario. There could be a lot of dialog popping up frequently in an app.
I wonder if it is necessary to override dispose() function and explicitly close all streams in BLoCProvider. It seems existing tutorials didn't mention it.
dart flutter rxdart asked Nov 20 '18 at 10:54
First_Strike
1128
add a comment |
There are some scenarios where screens with their respective BLoCs are frequently created and closed. So I'm somewhat concerned about memory safety of the Streams instances created in this process, because it doesn't seem they are disposed somewhere or whether they are GC-ed. This clearly depends on the specific implementation of DART libraries and flutter. So if you know about their behavior, please let me know.
These are some scenarios I have encountered.
- Multi-tab browser-like application.
- Navigation through screens. (But it's not that harmful.)
- showDialog() senarios when there are BLoCs inside the dialog. This is a far more common senario. There could be a lot of dialog popping up frequently in an app.
I wonder if it is necessary to override dispose() function and explicitly close all streams in BLoCProvider. It seems existing tutorials didn't mention it.
dart flutter rxdart asked Nov 20 '18 at 10:54
First_Strike
1128
There are some scenarios where screens with their respective BLoCs are frequently created and closed. So I'm somewhat concerned about memory safety of the Streams instances created in this process, because it doesn't seem they are disposed somewhere or whether they are GC-ed. This clearly depends on the specific implementation of DART libraries and flutter. So if you know about their behavior, please let me know.
These are some scenarios I have encountered.
- Multi-tab browser-like application.
- Navigation through screens. (But it's not that harmful.)
- showDialog() senarios when there are BLoCs inside the dialog. This is a far more common senario. There could be a lot of dialog popping up frequently in an app.
I wonder if it is necessary to override dispose() function and explicitly close all streams in BLoCProvider. It seems existing tutorials didn't mention it.
dart flutter rxdart dart flutter rxdart asked Nov 20 '18 at 10:54
First_Strike
1128
asked Nov 20 '18 at 10:54
First_Strike
1128
asked Nov 20 '18 at 10:54
First_Strike
1128
asked Nov 20 '18 at 10:54
First_Strike
1128
asked Nov 20 '18 at 10:54
First_Strike
1128
1128
add a comment |
add a comment |
1 Answer
1
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oldest
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Streams will properly be cleaned as long as they aren't used anymore.
The thing is, to simply removing the variable isn't enough to unsure it's unused. It could still run in background.
You need to call Sink.close() so that it stops the associated StreamController, to ensure resources can later be freed by the GC.
To do that, you have to use StatefulWidget.dispose method:
abstract class MyBloc {
Sink foo;
Sink bar;
}
class MyWiget extends StatefulWidget {
@override
_MyWigetState createState() => _MyWigetState();
}
class _MyWigetState extends State<MyWiget> {
MyBloc bloc;
@override
void dispose() {
bloc.bar.close();
bloc.foo.close();
super.dispose();
}
@override
Widget build(BuildContext context) {
// ...
}
}
answered Nov 20 '18 at 11:03
Rémi Rousselet
24.8k24682
Do you think it's always better to use access a bloc via an interface than using a provider which effectively uses an inherited widget?
– stt106
Nov 20 '18 at 11:10
@stt106 What do you mean? An interface doesn't replace the provider, nor does the provider replace the interface
– Rémi Rousselet
Nov 20 '18 at 11:13
will chat to you on slack.
– stt106
Nov 20 '18 at 11:14
Oh, thanks. So it seems we need to close the Streams in the dispose() function. But there are some other problems with this solution. InheritedWidget has their own lifecycle. I'm not so sure about this, but is it likely that either user or flutter engine triggers an unintended disposal of InheritedWidget? Because I've seen in some tutorials that BLoCs becomes shared and InheritedWidget are created and re-assigned everywhere.
– First_Strike
Nov 20 '18 at 11:57
You need both an Inheritedwidget and a StatefulWidget
– Rémi Rousselet
Nov 20 '18 at 12:05
add a comment |
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1 Answer
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Streams will properly be cleaned as long as they aren't used anymore.
The thing is, to simply removing the variable isn't enough to unsure it's unused. It could still run in background.
You need to call Sink.close() so that it stops the associated StreamController, to ensure resources can later be freed by the GC.
To do that, you have to use StatefulWidget.dispose method:
abstract class MyBloc {
Sink foo;
Sink bar;
}
class MyWiget extends StatefulWidget {
@override
_MyWigetState createState() => _MyWigetState();
}
class _MyWigetState extends State<MyWiget> {
MyBloc bloc;
@override
void dispose() {
bloc.bar.close();
bloc.foo.close();
super.dispose();
}
@override
Widget build(BuildContext context) {
// ...
}
}
answered Nov 20 '18 at 11:03
Rémi Rousselet
24.8k24682
Do you think it's always better to use access a bloc via an interface than using a provider which effectively uses an inherited widget?
– stt106
Nov 20 '18 at 11:10
@stt106 What do you mean? An interface doesn't replace the provider, nor does the provider replace the interface
– Rémi Rousselet
Nov 20 '18 at 11:13
will chat to you on slack.
– stt106
Nov 20 '18 at 11:14
Oh, thanks. So it seems we need to close the Streams in the dispose() function. But there are some other problems with this solution. InheritedWidget has their own lifecycle. I'm not so sure about this, but is it likely that either user or flutter engine triggers an unintended disposal of InheritedWidget? Because I've seen in some tutorials that BLoCs becomes shared and InheritedWidget are created and re-assigned everywhere.
– First_Strike
Nov 20 '18 at 11:57
You need both an Inheritedwidget and a StatefulWidget
– Rémi Rousselet
Nov 20 '18 at 12:05
add a comment |
Streams will properly be cleaned as long as they aren't used anymore.
The thing is, to simply removing the variable isn't enough to unsure it's unused. It could still run in background.
You need to call Sink.close() so that it stops the associated StreamController, to ensure resources can later be freed by the GC.
To do that, you have to use StatefulWidget.dispose method:
abstract class MyBloc {
Sink foo;
Sink bar;
}
class MyWiget extends StatefulWidget {
@override
_MyWigetState createState() => _MyWigetState();
}
class _MyWigetState extends State<MyWiget> {
MyBloc bloc;
@override
void dispose() {
bloc.bar.close();
bloc.foo.close();
super.dispose();
}
@override
Widget build(BuildContext context) {
// ...
}
}
answered Nov 20 '18 at 11:03
Rémi Rousselet
24.8k24682
Do you think it's always better to use access a bloc via an interface than using a provider which effectively uses an inherited widget?
– stt106
Nov 20 '18 at 11:10
@stt106 What do you mean? An interface doesn't replace the provider, nor does the provider replace the interface
– Rémi Rousselet
Nov 20 '18 at 11:13
will chat to you on slack.
– stt106
Nov 20 '18 at 11:14
Oh, thanks. So it seems we need to close the Streams in the dispose() function. But there are some other problems with this solution. InheritedWidget has their own lifecycle. I'm not so sure about this, but is it likely that either user or flutter engine triggers an unintended disposal of InheritedWidget? Because I've seen in some tutorials that BLoCs becomes shared and InheritedWidget are created and re-assigned everywhere.
– First_Strike
Nov 20 '18 at 11:57
You need both an Inheritedwidget and a StatefulWidget
– Rémi Rousselet
Nov 20 '18 at 12:05
add a comment |
Streams will properly be cleaned as long as they aren't used anymore.
The thing is, to simply removing the variable isn't enough to unsure it's unused. It could still run in background.
You need to call Sink.close() so that it stops the associated StreamController, to ensure resources can later be freed by the GC.
To do that, you have to use StatefulWidget.dispose method:
abstract class MyBloc {
Sink foo;
Sink bar;
}
class MyWiget extends StatefulWidget {
@override
_MyWigetState createState() => _MyWigetState();
}
class _MyWigetState extends State<MyWiget> {
MyBloc bloc;
@override
void dispose() {
bloc.bar.close();
bloc.foo.close();
super.dispose();
}
@override
Widget build(BuildContext context) {
// ...
}
}
answered Nov 20 '18 at 11:03
Rémi Rousselet
24.8k24682
Streams will properly be cleaned as long as they aren't used anymore.
The thing is, to simply removing the variable isn't enough to unsure it's unused. It could still run in background.
You need to call Sink.close() so that it stops the associated StreamController, to ensure resources can later be freed by the GC.
To do that, you have to use StatefulWidget.dispose method:
abstract class MyBloc {
Sink foo;
Sink bar;
}
class MyWiget extends StatefulWidget {
@override
_MyWigetState createState() => _MyWigetState();
}
class _MyWigetState extends State<MyWiget> {
MyBloc bloc;
@override
void dispose() {
bloc.bar.close();
bloc.foo.close();
super.dispose();
}
@override
Widget build(BuildContext context) {
// ...
}
}
answered Nov 20 '18 at 11:03
Rémi Rousselet
24.8k24682
answered Nov 20 '18 at 11:03
Rémi Rousselet
24.8k24682
answered Nov 20 '18 at 11:03
Rémi Rousselet
24.8k24682
answered Nov 20 '18 at 11:03
Rémi Rousselet
24.8k24682
24.8k24682
Do you think it's always better to use access a bloc via an interface than using a provider which effectively uses an inherited widget?
– stt106
Nov 20 '18 at 11:10
@stt106 What do you mean? An interface doesn't replace the provider, nor does the provider replace the interface
– Rémi Rousselet
Nov 20 '18 at 11:13
will chat to you on slack.
– stt106
Nov 20 '18 at 11:14
Oh, thanks. So it seems we need to close the Streams in the dispose() function. But there are some other problems with this solution. InheritedWidget has their own lifecycle. I'm not so sure about this, but is it likely that either user or flutter engine triggers an unintended disposal of InheritedWidget? Because I've seen in some tutorials that BLoCs becomes shared and InheritedWidget are created and re-assigned everywhere.
– First_Strike
Nov 20 '18 at 11:57
You need both an Inheritedwidget and a StatefulWidget
– Rémi Rousselet
Nov 20 '18 at 12:05
add a comment |
Do you think it's always better to use access a bloc via an interface than using a provider which effectively uses an inherited widget?
– stt106
Nov 20 '18 at 11:10
@stt106 What do you mean? An interface doesn't replace the provider, nor does the provider replace the interface
– Rémi Rousselet
Nov 20 '18 at 11:13
will chat to you on slack.
– stt106
Nov 20 '18 at 11:14
Oh, thanks. So it seems we need to close the Streams in the dispose() function. But there are some other problems with this solution. InheritedWidget has their own lifecycle. I'm not so sure about this, but is it likely that either user or flutter engine triggers an unintended disposal of InheritedWidget? Because I've seen in some tutorials that BLoCs becomes shared and InheritedWidget are created and re-assigned everywhere.
– First_Strike
Nov 20 '18 at 11:57
You need both an Inheritedwidget and a StatefulWidget
– Rémi Rousselet
Nov 20 '18 at 12:05
Do you think it's always better to use access a bloc via an interface than using a provider which effectively uses an inherited widget?
– stt106
Nov 20 '18 at 11:10
Do you think it's always better to use access a bloc via an interface than using a provider which effectively uses an inherited widget?
– stt106
Nov 20 '18 at 11:10
@stt106 What do you mean? An interface doesn't replace the provider, nor does the provider replace the interface
– Rémi Rousselet
Nov 20 '18 at 11:13
@stt106 What do you mean? An interface doesn't replace the provider, nor does the provider replace the interface
– Rémi Rousselet
Nov 20 '18 at 11:13
will chat to you on slack.
– stt106
Nov 20 '18 at 11:14
will chat to you on slack.
– stt106
Nov 20 '18 at 11:14
Oh, thanks. So it seems we need to close the Streams in the dispose() function. But there are some other problems with this solution. InheritedWidget has their own lifecycle. I'm not so sure about this, but is it likely that either user or flutter engine triggers an unintended disposal of InheritedWidget? Because I've seen in some tutorials that BLoCs becomes shared and InheritedWidget are created and re-assigned everywhere.
– First_Strike
Nov 20 '18 at 11:57
Oh, thanks. So it seems we need to close the Streams in the dispose() function. But there are some other problems with this solution. InheritedWidget has their own lifecycle. I'm not so sure about this, but is it likely that either user or flutter engine triggers an unintended disposal of InheritedWidget? Because I've seen in some tutorials that BLoCs becomes shared and InheritedWidget are created and re-assigned everywhere.
– First_Strike
Nov 20 '18 at 11:57
You need both an Inheritedwidget and a StatefulWidget
– Rémi Rousselet
Nov 20 '18 at 12:05
You need both an Inheritedwidget and a StatefulWidget
– Rémi Rousselet
Nov 20 '18 at 12:05
add a comment |
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