檢索科特林內的地圖

Question

我有這樣的數據結構：

        val drinks = hashMapOf(
        "cola" to hashMapOf(
            "price" to 36,
            "amount" to 15
        )
    )

我使用消防站，想取回價格。

        db.collection("category").document("drinks").get()
        .addOnSuccessListener {documentSnapshot->
            documentSnapshot.data?.forEach {
            //it ->  Map.Entry<String!,Any!>
                Log.d(TAG, "for each data: ${it.key} ${it.value}")
            }
            if (documentSnapshot != null && documentSnapshot.exists()) {
                Log.d(TAG, "read data: ${documentSnapshot["sultan"]}")
            } else {
                Log.d(TAG, "Current data: null")
            }
    }

我試圖將其轉換為對象列表，但沒有任何幫助

Answer 1

使用Kotlin中的Firebase處理數據的更好方法。

.addOnSuccessListener { docsSnapshot ->
    for (docSnapshot in docsSnapshot.documents) {
        val hashmap = docSnapshot.data
        hashmap?.put("id", docSnapshot.id)
        Log.e("hashmap", hashmap) // This hashmap holds your document id and rest of data.
        val Data = Gson().toJson(hashmap)
        val docsData = Gson().fromJson<Drinks>(Data, Drinks::class.java)
        Log.e("docsData", docsData) // Now you can access what type of data you need.
    }
}

POKO供您參考：

class Drinks{
    val id : String,
    val amount : Long,
    val price : Long,
}