How to reload specific widgets in flutter without its parent? - flutter

Question

I am building an app in Flutter,that supposed to be a social network app-similar to faceboook.
I have implemented a like button-when pressed is sending the server the request,and then depending on the status code it sets the state.My problem begins when the setState() is rendering again the avatar picture,or creating it again from scratch(the avatar is stored in a 64base String).
the likePress is a future that sends the request and then sets the boolean isLiked accordingly.
this is the creating of the like button:
buildLikeButton(int ownerId, int postId) {
return RepaintBoundary(
child: FutureBuilder<bool>(
future: getLike(ownerId, postId),
builder: (BuildContext context, AsyncSnapshot<bool> snapshot) {
IconButton likeButton;
if (snapshot.hasData) {
isLiked = snapshot.data;
likeButton = createLikeButton(ownerId, postId);
} else if (snapshot.hasError) {
isLiked = false;
likeButton = createLikeButton(ownerId, postId);
print('the snapshot has an error ${snapshot.error}');
} else {
isLiked = false;
likeButton = createLikeButton(ownerId, postId);
}
return likeButton;
}));
}
createLikeButton(int ownerId, int postId) {
return IconButton(
icon: returnLikeIcon(isLiked),
color: Theme.of(context).accentColor,
onPressed: () async {
if (this.mounted) {
setState(() {
Future lol = likePress(ownerId, postId).then((onValue) {});
});
}
},
);
}
and this is the creation of the avatar:
createAvatar(BuildContext context, avatar_base64, int ownerId) {
Uint8List bytes = base64Decode(avatar_base64.split(',').last);
return RepaintBoundary(
child: CircleAvatar(
radius: 25.0,
backgroundImage: MemoryImage(bytes),
backgroundColor: Colors.transparent,
));
}
The widget that displays them together is the Post widget which i have created for this project,and this is it's build function:
Widget build(BuildContext context) {
return InkWell(
borderRadius: BorderRadius.circular(0.2),
child: Container(
decoration: BoxDecoration(boxShadow: [
BoxShadow(
color: Theme.of(context).primaryColor,
blurRadius: 1.0,
spreadRadius: 1.0, // has the effect of extending the shadow
offset: Offset(
5.0, // horizontal, move right 10
5.0, // vertical, move down 10
),
),
]),
child: Card(
elevation: 10.0,
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Flexible(
fit: FlexFit.loose,
child: postInfo(context, time, ownerId)),
Divider(
thickness: 1.0,
height: 10.0,
indent: 10.0,
endIndent: 10.0,
),
postContent(content),
Divider(
thickness: 1.0,
height: 10.0,
indent: 10.0,
endIndent: 10.0,
),
createButtonBar(ownerId, postId),
],
)),
));
}
postInfo is just a FutureBuilder that builds the ListTile that adds up the avatar and the name, and createButtonBar creates the like button and 2 more buttons.
I would like to change the icon when the user presses the like button,but only if the server has responded with the right status code and without rendering and creating the whole Post widget over again.Thank you for the trouble!

Answer 1

This means that the avatar is beneath the point where you are calling setState(() {}). In your case, the method is probably inside that particular widget and the widget is being rebuilt.
I suggest for you to solve the problem to move the creation of the avatar above. In this way, if you need to rebuild the object the avatar will not be created anew but simply placed within the new widget. Place some debugPrints around to speed up the process and try to refactor the code to see if you missed something.

Answer 2

After taking a better look at my code,I decided to create a different Widget for each part of the post,so I can initialize everything that will not be built again outside of the build method.
so if you want to exclude a widget from the setState() method, you need to move it outside the current widget(by creating a widget for it) and just create an instance of it as a parameter in the constructor.
In more detail,I created a class named PostHeader and there i created the avatar and the ListTile containing it,then i created an instance of it inside the Post class,so it is not created inside the build method of the Post class.