从 Firebase 获取文档 ID 使用 Flutter 查询

Question

If I have a collection called userNames and I use a firebase query to search for a document that a database field uid matches the current user ID, how do I print the document ID of the documents that contain that term?

Answer 1

A query can return multiple documents that match the given condition and returns a QuerySnapshot (that contains zero or many DocumentSnapshots ).

FirebaseFirestore.instance
  .collection('userNames')
  .where('uid', isEqualTo: FirebaseAuth.instance.currentUser!.uid)
  .get()
  .then((value) {
    value.docs.forEach((element) {
      print(element.id);
    });
  });

Here value.docs is a list of all the documents included in this snapshot and each of them has id property (the document ID).