我想从 firestore 中的集合中获取多个字段的文档

Question

"titleList" is a list of names of collection documents. For "questionMaps", the document name is the key and the "text" field of the document's array type is the value. I would like to make this questionMaps have 30 elements, but I have tried using a for statement but it did not work. I would like to know how to solve this problem. This is my code.

Map questionMaps = {};
for (int i = 0; i < 30; i++) {
   FirebaseFirestore.instance
      .collection("titles")
      .doc(widget.titleList[i])
      .get()
      .then(
      (ref) {
         List questions = ref.get("text");
         questionMaps[widget.titleList[i]] = questions;
        },
       );
      }

Answer 1

consider trying to get the whole snapshot of the collection, then run your logic over it. since you said that your documents ids are the names in your titleList list, consider this:

   Map questionMaps = {};

   final querySnapshot = await FirebaseFirestore.instance.collection("titles").get();

   querySnapshot.docs.forEach((doc) {
     List questions = (doc.data() as Map<String, dynamic>)["text"];
     questionMaps[doc.id] = questions; 
   });

this will register your questions List for each doc.id , then you can get it based on titleList like this as example:

print(questionMaps[titleList[0]]); // will get you questions which have the  name key.