如何使用kotlin firestore获得客户订购的相似和不相似项目的总权重&用于循环/迭代地图集合

val db = FirebaseFirestore.getInstance()
val collectionRef = db.collection("orders")

val query = collectionRef.whereEqualTo("customer", "客户ID")
val orders = mutableListOf<DocumentSnapshot>()

query.get().addOnSuccessListener { querySnapshot ->
    for (document in querySnapshot.documents) {
        orders.add(document)
    }

    // 在这里处理获取到的订单数据
}.addOnFailureListener { exception ->
    // 处理获取订单数据失败的情况
}

var similarWeight = 0
var dissimilarWeight = 0

for (order in orders) {
    val weight = order.getLong("weight") ?: 0

    if (order.getBoolean("similar") == true) {
        similarWeight += weight.toInt()
    } else {
        dissimilarWeight += weight.toInt()
    }
}

// 在这里可以使用 similarWeight 和 dissimilarWeight 进行后续操作

val parentDocRef = db.collection("parentCollection").document("parentDocument")
val childCollectionRef = parentDocRef.collection("childCollection")

childCollectionRef.get().addOnSuccessListener { querySnapshot ->
    for (document in querySnapshot.documents) {
        // 在这里处理子集合文档数据
    }
}.addOnFailureListener { exception ->
    // 处理获取子集合文档数据失败的情况
}