flutter - 避免整个小部件重建

Question

Trying a 'like button' within a Future builder with many other widgets as below,

onPressed: () {
    if (aleadyLiked.length > 0) {
        unlike(profileId);
     } else {
        like(profileId);
     }
   setState(() {});
 },

And this is how my future builder starts,

@override
Widget build(BuildContext context) {
return FutureBuilder(
  future: getProfile(profileId), 
  builder: (context, snapshot) {
  =======Other widgets here======
  }

Issue is onPressed of the like icon-button I am doing the setState() which is causing the whole Future builder to reload, Is there a way just to update the Like Button and the Like count, I was thinking to use some client side counter logic which callbacks to actual DB updates.Please help.

Loading Profile part on initState() can be achieved, but how to handle updating and reflecting 'Likes', can that Like-button region alone be reloaded?

Answer 1

You should not get this User Profile like this, but what you can do rather, you can get the user profile inside the initState, and before data is not loaded you can show either loader of something.

Something like this...

  User _user;
  
  Future<User> getUserProfile(profileId) async{
    ///Todo : Implementation of get User Profile
  }
  
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    getUserProfile("userId").then((user){
      setState(() {
        _user =user;
      });
    })
  }

@override
  Widget build(BuildContext context) {
    return Scaffold(
      body: this._user == null ? CircularProgressIndicator() : UserWidget(),
    );
  }

Answer 2

So this is how I finally achieved it,

void initState() {
 getProfile(profileId).then((user){
  setState(() {
    _profile =user;
    _counter =_profile.profilelikes.length;
    _isAlreadyLiked=_profile.allreadyliked.length > 0;
  });
 });
 super.initState();
}

And OnPressed() is

                                                            onPressed: () {
                                                              if (_isAlreadyLiked) {
                                                                unlike(profileId);
                                                                setState(() {
                                                                  _counter--;
                                                                  _isAlreadyLiked=false;
                                                                });
                                                              } else {
                                                                like(profileId);
                                                                setState(() {
                                                                  _counter++;
                                                                  _isAlreadyLiked=true;
                                                                });
                                                              }
                                                            },

Downside: The likes by other users will reflect on Wiget reload only, which is fine for me, for now.