for in loop is only storing the last data in the Map-CodePudding

This is the code that im developing to get a collection from Firestore and store all its data in another map

onPressed: () async {
  Map<String, dynamic> data = {};
  await FirebaseFirestore.instance.collection('primary').get() .then((values) {
    for (var I in values.docs) {
      data.addAll(i.data());
    }
    print(data);
  });
},

if I just print i.id, I will get all 9 ids that are available. But, by doing this to copy all the data from the map, when I print the Map data, Im only Storting the last value. Ive tried to use forEach but happened the same

CodePudding user response：

You have to make data a List<Map<String, dynamic>> instead of Map<String, dynamic> so you can add values to it instead of overwriting it the whole time.

So do this:

onPressed: () async {
  List<Map<String, dynamic>> data = {};
  await FirebaseFirestore.instance.collection('primary').get().then((snapshots) {
    for (var doc in snapshots.docs) {
      data.add(doc.data());
    }
  });
  print(data);
},