我有一个Firebase数据库,我想从那里检索数据列表并存储到ArrayList中。
产品模型很好,可以正常工作。
class Product(var pName: String?, var pUnit: Int, var pPrice: Double, var pAmount: Double)
但是以某种方式我无法从数据库中获取“项目”列表。我想要的是获取pname
,punit
,pprice
和pamount
并将其存储在ArrayList<Product>
我对数据库的引用是这个;
ref = FirebaseDatabase.getInstance().getReference().child("Sales")
ref.addValueEventListener(object : ValueEventListener{
override fun onCancelled(p0: DatabaseError) {
}
override fun onDataChange(p0: DataSnapshot) {
var sira: Int = 0
ref.addListenerForSingleValueEvent(object : ValueEventListener {
override fun onCancelled(p0: DatabaseError) {
}
override fun onDataChange(p1: DataSnapshot) {
println("onDataChange")
if (p0.exists()) {
list.clear()
for (h in p0.children) {
val dateR = h.child("date").value.toString()
val discountR = h.child("discount").value.toString()
val dueR = h.child("due").value.toString()
val nameR = h.child("name").value.toString()
val totalR = h.child("total").value.toString()
val subtotalR = h.child("subTotal").value.toString()
val timeR = h.child("time").value.toString()
val name = h.child("pname").value.toString()
val unit = h.child("punit").value.toString()
val price = h.child("pprice").value.toString()
val amount = h.child("pamount").value.toString()
productList.add(Product(name, unit.toInt(), price.toDouble(), amount.toDouble()))
但是,请帮助我在这里做错了什么。任何帮助表示赞赏。
谢谢。
您可以尝试:使用GenericTypeIndicator获取列表数据
private lateinit var database: DatabaseReference
private var productList: ArrayList<Product> = arrayListOf()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
database = FirebaseDatabase.getInstance().getReference("Sales")
database.addValueEventListener(object: ValueEventListener {
override fun onCancelled(p0: DatabaseError) {
}
override fun onDataChange(p0: DataSnapshot) {
productList.clear()
for (snapshot in p0.children) {
if (snapshot.hasChild("items")) {
val generic: GenericTypeIndicator<List<Product>> =
object : GenericTypeIndicator<List<Product>>() {}
val items = snapshot.child("items").getValue(generic)
items?.let { productList.addAll(it) }
}
}
}
})
}
class Product {
var pName: String? = null
var pUnit: Int? = null
var pPrice: Double? = null
var pAmount: Double? = null
}