Flutter从QuerySnapshot转换为将来的<List <Map <dynamic <dynamic，dynamic >>>

Question

如何返回QuerySnapshot作为Future >>？

程式码片段：

Future <List<Map<dynamic, dynamic>>>() {
List<Map<dynamic,dynamic>> list;
.....

.....
QuerySnapshot collectionSnapshot = await collectionRef.getDocuments();

list = collectionSnapshot.documents;  <--- ERROR
return list;

}

我认为我需要使用的Map，但无法绕开它。

Answer 1

collectionSnapshot.documents返回List而不是List类型，您将需要将Documentsnapshots的List转换为List>。我是这样的：

Future <List<Map<dynamic, dynamic>>> getCollection() async{
List<DocumentSnapshot> templist;
List<Map<dynamic, dynamic>> list = new List();
CollectionReference collectionRef = Firestore.instance.collection("path");
QuerySnapshot collectionSnapshot = await collectionRef.getDocuments();

templist = collectionSnapshot.documents; // <--- ERROR

list = templist.map((DocumentSnapshot docSnapshot){
  return docSnapshot.data;
}).toList();

return list;
}