Flutter - 如何第一次添加（创建）嵌套集合，然后下次在 Firestore 中添加字段（更新集合）

Question

在这种方法中，我在第一次保存一组（锻炼组）时创建一个新的集合（“锻炼”）。一次锻炼将有多个锻炼。那么如何将下一个练习添加到同一锻炼中？

_saveExerciseSetForUser() {
if (currentUser != null) {
  FirebaseFirestore.instance
      .collection('users')
      .doc(currentUser!.uid)
      .collection("workouts")
      .doc()
      .collection("exercises")
      .doc(exerciseId)
      .collection("sets")
      .doc()
      .set({
    
    "setNo.": setCount,
    "weight": weightController.text,
    "reps": repsController.text,
    "toFailure": false
  }).then((value) => {
    
  });
 }
}

Answer 1

为了在现有锻炼中添加新锻炼，您需要跟踪文档或锻炼 ID。获得锻炼 ID 后，您将知道可以将新锻炼添加到的路径。 users/$userId/workouts/$workoutId/exercises/$exerciseId/sets

Future<void> _saveExerciseSetForUser([String? workoutId]) async {
  if (currentUser == null) {
    return;
  }

  final data = {
    "setNo.": setCount,
    "weight": weightController.text,
    "reps": repsController.text,
    "toFailure": false,
  };

  final workoutDoc = FirebaseFirestore.instance
    .collection('users')
    .doc(currentUser!.uid)
    .collection("workouts")
    // if workoutId is null, this will create a new workout
    .doc(workoutId);

  // save doc id somewhere
  final workoutDocId = workoutDoc.id;

  await workoutDoc.collection("exercises")
    .doc(exerciseId)
    .collection("sets")
    .doc()
    .set(data);
}