从 FirebaseFirestore 查询数据不起作用

Question

I want to query the data in a collection in Firestore. This is the code I used in initState:

  @override
  void initState() {
    super.initState();
    var nws;
    FirebaseFirestore.instance
      .collection('News')
      .get()
      .then((QuerySnapshot querySnapshot) {
        querySnapshot.docs.forEach((doc) {
        nws = doc["news"] // PRINT STATEMENT 1 
        print(nws);
        });
    });
    print(nws); // PRINT STATEMENT 2
  }

The issue I am facing is that PRINT STATEMENT 1 is correctly printing the data in Firestore but PRINT STATEMENT 1 is printing null . What is my mistake? I want to use nws in a Text Widget.

Answer 1

var news;
void getFirebaseData() async {
await FirebaseFirestore.instance.collection("News").get().then((querySnapshot) {
  querySnapshot.docs.forEach((result) {
    setState(() {
      news = result.data();
    });
   });
  });
print("***2***" +  news['news'].toString());
}

Let me know if this works out, It's tested and working. You should handle null values I would suggest adding a null value checker like

if (result.data().isEmpty)