createState method not always called when creating new StatefulWidget
I have a collection of simple objets that sometimes changes. I am using a ListView to render those objects, basically text. When my collection changes the list is rebuild with the new objects, so if the list changes from 1 to 3 items, I see 3 items, but the first one keeps its previous value.
I've noticed that the method "createState" is not called in all cases when I create a new CustomTextField (in the example above, it is called only when new elements are added to the list).
How do I make sure my list is updated properly when my collection changes?
My parent widget builds a list of text fields:
...
@override
Widget build(BuildContext context) {
...
var list = <Widget>;
collection.forEach((item)
var widget = CustomTextField(
content: item,
);
list.add(widget);
...
return new ListView(
children: list,
);
);
...
My CustomTextField definition:
class CustomTextField extends StatefulWidget
final MediaContent content;
CustomTextField(
Key key,
this.content,
) : super(key: key);
@override
CustomTextFieldState createState()
return CustomTextFieldState();
...
MediaContent is a very simple object containing some text:
class MediaContent
String textData;
ContentType type;
MediaContent(
this.type,
);
dart
flutter asked Nov 12 '18 at 0:12
MikiMiki
76416
add a comment |
I have a collection of simple objets that sometimes changes. I am using a ListView to render those objects, basically text. When my collection changes the list is rebuild with the new objects, so if the list changes from 1 to 3 items, I see 3 items, but the first one keeps its previous value.
I've noticed that the method "createState" is not called in all cases when I create a new CustomTextField (in the example above, it is called only when new elements are added to the list).
How do I make sure my list is updated properly when my collection changes?
My parent widget builds a list of text fields:
...
@override
Widget build(BuildContext context) {
...
var list = <Widget>;
collection.forEach((item)
var widget = CustomTextField(
content: item,
);
list.add(widget);
...
return new ListView(
children: list,
);
);
...
My CustomTextField definition:
class CustomTextField extends StatefulWidget
final MediaContent content;
CustomTextField(
Key key,
this.content,
) : super(key: key);
@override
CustomTextFieldState createState()
return CustomTextFieldState();
...
MediaContent is a very simple object containing some text:
class MediaContent
String textData;
ContentType type;
MediaContent(
this.type,
);
dart
flutter asked Nov 12 '18 at 0:12
MikiMiki
76416
I'm experiencing this same issue when creating the same widget in succession (even when I use the "new" keyword during creation). Did you find a solution for this?
– dazza5000
Jan 28 at 0:38
@dazza5000 see if my answer works for you
– Guilherme Torres Castro
Jan 31 at 15:09
will try it out shortly - thank you for the help
– dazza5000
Jan 31 at 15:24
@GuilhermeTorresCastro - that was it - thank you
– dazza5000
Feb 1 at 1:10
add a comment |
I have a collection of simple objets that sometimes changes. I am using a ListView to render those objects, basically text. When my collection changes the list is rebuild with the new objects, so if the list changes from 1 to 3 items, I see 3 items, but the first one keeps its previous value.
I've noticed that the method "createState" is not called in all cases when I create a new CustomTextField (in the example above, it is called only when new elements are added to the list).
How do I make sure my list is updated properly when my collection changes?
My parent widget builds a list of text fields:
...
@override
Widget build(BuildContext context) {
...
var list = <Widget>;
collection.forEach((item)
var widget = CustomTextField(
content: item,
);
list.add(widget);
...
return new ListView(
children: list,
);
);
...
My CustomTextField definition:
class CustomTextField extends StatefulWidget
final MediaContent content;
CustomTextField(
Key key,
this.content,
) : super(key: key);
@override
CustomTextFieldState createState()
return CustomTextFieldState();
...
MediaContent is a very simple object containing some text:
class MediaContent
String textData;
ContentType type;
MediaContent(
this.type,
);
dart
flutter asked Nov 12 '18 at 0:12
MikiMiki
76416
I have a collection of simple objets that sometimes changes. I am using a ListView to render those objects, basically text. When my collection changes the list is rebuild with the new objects, so if the list changes from 1 to 3 items, I see 3 items, but the first one keeps its previous value.
I've noticed that the method "createState" is not called in all cases when I create a new CustomTextField (in the example above, it is called only when new elements are added to the list).
How do I make sure my list is updated properly when my collection changes?
My parent widget builds a list of text fields:
...
@override
Widget build(BuildContext context) {
...
var list = <Widget>;
collection.forEach((item)
var widget = CustomTextField(
content: item,
);
list.add(widget);
...
return new ListView(
children: list,
);
);
...
My CustomTextField definition:
class CustomTextField extends StatefulWidget
final MediaContent content;
CustomTextField(
Key key,
this.content,
) : super(key: key);
@override
CustomTextFieldState createState()
return CustomTextFieldState();
...
MediaContent is a very simple object containing some text:
class MediaContent
String textData;
ContentType type;
MediaContent(
this.type,
);
dart
flutter dart
flutter asked Nov 12 '18 at 0:12
MikiMiki
76416
asked Nov 12 '18 at 0:12
MikiMiki
76416
edited Nov 12 '18 at 16:59
Miki
asked Nov 12 '18 at 0:12
MikiMiki
76416
asked Nov 12 '18 at 0:12
MikiMiki
76416
asked Nov 12 '18 at 0:12
MikiMiki
76416
76416
I'm experiencing this same issue when creating the same widget in succession (even when I use the "new" keyword during creation). Did you find a solution for this?
– dazza5000
Jan 28 at 0:38
@dazza5000 see if my answer works for you
– Guilherme Torres Castro
Jan 31 at 15:09
will try it out shortly - thank you for the help
– dazza5000
Jan 31 at 15:24
@GuilhermeTorresCastro - that was it - thank you
– dazza5000
Feb 1 at 1:10
add a comment |
I'm experiencing this same issue when creating the same widget in succession (even when I use the "new" keyword during creation). Did you find a solution for this?
– dazza5000
Jan 28 at 0:38
@dazza5000 see if my answer works for you
– Guilherme Torres Castro
Jan 31 at 15:09
will try it out shortly - thank you for the help
– dazza5000
Jan 31 at 15:24
@GuilhermeTorresCastro - that was it - thank you
– dazza5000
Feb 1 at 1:10
I'm experiencing this same issue when creating the same widget in succession (even when I use the "new" keyword during creation). Did you find a solution for this?
– dazza5000
Jan 28 at 0:38
I'm experiencing this same issue when creating the same widget in succession (even when I use the "new" keyword during creation). Did you find a solution for this?
– dazza5000
Jan 28 at 0:38
@dazza5000 see if my answer works for you
– Guilherme Torres Castro
Jan 31 at 15:09
@dazza5000 see if my answer works for you
– Guilherme Torres Castro
Jan 31 at 15:09
will try it out shortly - thank you for the help
– dazza5000
Jan 31 at 15:24
will try it out shortly - thank you for the help
– dazza5000
Jan 31 at 15:24
@GuilhermeTorresCastro - that was it - thank you
– dazza5000
Feb 1 at 1:10
@GuilhermeTorresCastro - that was it - thank you
– dazza5000
Feb 1 at 1:10
add a comment |
1 Answer
1
active
oldest
votes
You have to define unique Key for you collections itens, take a look at here:
https://www.youtube.com/watch?v=kn0EOS-ZiIc
answered Jan 31 at 15:08
Guilherme Torres CastroGuilherme Torres Castro
9,24744684
add a comment |
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1 Answer
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1 Answer
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oldest
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votes
You have to define unique Key for you collections itens, take a look at here:
https://www.youtube.com/watch?v=kn0EOS-ZiIc
answered Jan 31 at 15:08
Guilherme Torres CastroGuilherme Torres Castro
9,24744684
add a comment |
You have to define unique Key for you collections itens, take a look at here:
https://www.youtube.com/watch?v=kn0EOS-ZiIc
answered Jan 31 at 15:08
Guilherme Torres CastroGuilherme Torres Castro
9,24744684
add a comment |
You have to define unique Key for you collections itens, take a look at here:
https://www.youtube.com/watch?v=kn0EOS-ZiIc
answered Jan 31 at 15:08
Guilherme Torres CastroGuilherme Torres Castro
9,24744684
You have to define unique Key for you collections itens, take a look at here:
https://www.youtube.com/watch?v=kn0EOS-ZiIc
answered Jan 31 at 15:08
Guilherme Torres CastroGuilherme Torres Castro
9,24744684
answered Jan 31 at 15:08
Guilherme Torres CastroGuilherme Torres Castro
9,24744684
answered Jan 31 at 15:08
Guilherme Torres CastroGuilherme Torres Castro
9,24744684
answered Jan 31 at 15:08
Guilherme Torres CastroGuilherme Torres Castro
9,24744684
9,24744684
add a comment |
add a comment |
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I'm experiencing this same issue when creating the same widget in succession (even when I use the "new" keyword during creation). Did you find a solution for this?
– dazza5000
Jan 28 at 0:38
@dazza5000 see if my answer works for you
– Guilherme Torres Castro
Jan 31 at 15:09
will try it out shortly - thank you for the help
– dazza5000
Jan 31 at 15:24
@GuilhermeTorresCastro - that was it - thank you
– dazza5000
Feb 1 at 1:10