flutter firebase database initState issue

Question

My app has a object Company that has an attribute shopList. The shoplist will get data from firebase database in void initState() .

Company(name: 'Storm',
      about: 'xxxxxxxxxxxx',
      backdropPhoto: 'assets/hk.jpg',
      shopList: [],
      location: 'HK',
      logo: 'assets/logo.png',
      president: 'Grand Production House');

The shoplist is supposed to have 5 different shops, but I don't know why it will have 5 shops with the same data.

Code:

class CompanyDetailsPage extends StatefulWidget {

    CompanyDetailsPage(
      {@required AnimationController controller, this.context})
      : animation = new CompanyDetsIntroAnimation(controller);

  final BuildContext context;

  final CompanyDetsIntroAnimation animation;
  @override
  _CompanyDetailsPageState createState() => _CompanyDetailsPageState();
}

class _CompanyDetailsPageState extends State<CompanyDetailsPage> {

  Shop shopItems;

  Company storm = Company(
      name: 'Storm',
      about: 'xxxxxxxxxxxx',
      backdropPhoto: 'assets/hk.jpg',
      shopList: [],
      location: 'HK',
      logo: 'assets/logo.png',
      president: 'Grand Production House');

  DatabaseReference databaseReference = FirebaseDatabase.instance.reference();

  @override
  void initState() {
    super.initState();

    shopItems = Shop();

    databaseReference.child('HK').once().then((DataSnapshot snapshot) {
      Map uid = snapshot.value;
      uid.forEach((k,v) {
        Map shopMap = v['Shop'];

        shopMap.forEach((sk,sv) {
          shopItems.key = sk;
          shopItems.shopName = sv["ShopName"];
          shopItems.address = sv["ShopAddress"];
          shopItems.tel = sv["ShopTel"];
          shopItems.thumbnail = sv["Thumbnail"];


          debugPrint(shopItems.address);

          storm.shopList.add(shopItems);

          debugPrint(shopItems.key);
        });

      });

      for (int i = 0; i < storm.shopList.length; i++) {

        debugPrint("Username: ${storm.shopList[i].address }, User Id: ${storm.shopList[i].key}");

      }
    });
  }

Result from console:

Syncing files to device iPhone X...
flutter: -LM3JFMq5y9fNVA431QW
flutter: -LMHR9YQFqgKlnFArwEN
flutter: -LM3JH8KMha3aeN-YEq5
flutter: -LM3JJTFda0c3qKaKEaL
flutter: -LMIaUIBOhj1k6pjj9eY
flutter: ShopAddress: bbbbbb, ShopKey: -LMIaUIBOhj1k6pjj9eY
flutter: ShopAddress: bbbbbb, ShopKey: -LMIaUIBOhj1k6pjj9eY
flutter: ShopAddress: bbbbbb, ShopKey: -LMIaUIBOhj1k6pjj9eY
flutter: ShopAddress: bbbbbb, ShopKey: -LMIaUIBOhj1k6pjj9eY
flutter: ShopAddress: bbbbbb, ShopKey: -LMIaUIBOhj1k6pjj9eY

You should try naming variables with more descriptive words. It's hard to follow like this. If you debug the method, can you see the five different shops returned by firebase? — Sebastian
– Sebastian, Commented Sep 13, 2018 at 20:53
debugPrint(shopItems.address) print out 5 different address, then I put this shopItem in to shopList array of Company object. But I print the element of shopList array, it shows that all the items are the same. I couldn't find out whats the problem. — GPH
– GPH, Commented Sep 14, 2018 at 5:01

Sebastian · Accepted Answer · 2018-09-14 12:38:43Z

1

I think the problem may be where you are instantiating shopItems = Shop();.

Try removing it from there and do this

shopMap.forEach((sk,sv) {
//Create the instance here
  shopItems = Shop();

  shopItems.key = sk;
  shopItems.shopName = sv["ShopName"];
  shopItems.address = sv["ShopAddress"];
  shopItems.tel = sv["ShopTel"];
  shopItems.thumbnail = sv["Thumbnail"];


  debugPrint(shopItems.address);

  storm.shopList.add(shopItems);

  debugPrint(shopItems.key);
});

answered Sep 14, 2018 at 12:38

Sebastian

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1 Comment

GPH Over a year ago

Thank you very much! May I ask why the shopItem didn't change value?

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