How to set state to another class ? - Flutter

Question

I want to change the value of an integer in another class and rebuild this class so the bottom navigation bar items will change according to the integer

Here's the main class were the bottom navigation bar exists and the condition to hide or show the items :

class Home extends StatefulWidget { 
 static int showCard = 0;
@override
 _HomeState createState() => _HomeState();
}  

@override
 Widget build(BuildContext context) {
 ...

//the items to show and hide according to int showcard
 if (Home.showCard == 0)
              BottomNavigationBarItem(
                icon: Icon(
                  Icons.person_outlined,
                ),
                title: Text(
                  'Profile',
                ),
              ),
            if (Home.showCard != 0)
              BottomNavigationBarItem(
                icon: Icon(Icons.settings),
                title: Text(
                  'Settings',
                ),
              )

And here's the second class where i want to change the value of showcard to hide the profile section ad show the setting , i'm calling set state with on pressed in this class it's changing the value but not rebuilding the main class :

class Homehome extends StatefulWidget {
const Homehome({Key? key}) : super(key: key);
  @override
_HomehomeState createState() => _HomehomeState();
}   
  class _HomehomeState extends State<Homehome> {
   @override
  Widget build(BuildContext context) {
  ...
   child: RaisedButton(
                                  onPressed: () {
                                    setState(() {
                                      Home.showCard = 1;
                                    });

                                    Navigator.of(context)
                                        .push(MaterialPageRoute(
                                      builder: (context) => Green(),
                                    ));
                                  },

any suggestions ?

Does this answer your question? [Flutter setState to another class?](https://stackoverflow.com/questions/51798498/flutter-setstate-to-another-class) — Md. Yeasin Sheikh, Jan 19 '22 at 16:22

score 1 · Answer 1 · answered Jan 19 '22 at 15:20

1

You can use callback functions: have a look at this solution. https://stackoverflow.com/a/59832932/16479524

upvote if helpful :)

answered Jan 19 '22 at 15:20

Yash Bhansali

420
2
6

score 0 · Answer 2 · answered Jan 19 '22 at 14:45

0

You don't need to change the state. You should only update the state when you want to change something inside a widget, for instance a Text value or something like that.

Every time you change a value, it changes. If you want to change a 'visible value', then you have to change the state by setState method.

answered Jan 19 '22 at 14:45

Prodromos Sarakinou

809
4
16

I need to chenge the state so the value of showcard can change to 1 and it's working . the problem that i'm facing is that i want to rebuild the main class once the value of showcard has changed so the profile section will hide and the settings section will show – flutteruser Jan 19 '22 at 14:48
If you want to show the value of the 'showCard' value, then because you push again the previous page, the page will be rebuilt. Also, if you don't want to show this value '1' or '0' you won't need to change the state. The value will be changed either way, if it doesn't work, something else should go wrong. – Prodromos Sarakinou Jan 20 '22 at 08:25

score 0 · Answer 3 · answered Jan 19 '22 at 14:48

0

It sounds like you need to get a better understanding of state.

Widgets in Flutter live in a hierarchy. You should have a state in one widget, and then child widgets update based on this state. You can pass state changes down to child widgets using parameters.

Also, prefer to use proper data types for the situation. Don’t use a numerical data type like an int for showing or hiding a widget; use a bool (true or false).

answered Jan 19 '22 at 14:48

Martin Bean

38,379
25
128
201

I, m using an iteger because later on i might use three itemes to show and hide acording to the integer 1 2 and 3 , can you give me an example how can i can pass the state to solve my problem ? – flutteruser Jan 19 '22 at 14:55
That makes no sense. “Show” or “hide” doesn’t map to 1, 2, or 3. – Martin Bean Jan 19 '22 at 15:13

How to set state to another class ? - Flutter

3 Answers3