Kotlin Firebase：无法将 java.lang.String 类型的对象转换为 com.example.Model.perizinan 类型

Question

我正在尝试将数据从 Firebase 加载到 RecyclerView，我需要将数据从 Firebase 获取到 ArrayList 但我收到以下错误：

com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type com.example.Model.perizinan

这是我的班级：

class perizinan(val imageUrl:String, val namakegiatan:String, val keterangan:String, val waktuKegiatan:String, val presensiIzin:String, val tanggalkegiatan:String)
class izin(val perizinan:List<perizinan>)

这是我的代码：

fun readFirebaseDatabase(){

    val ref= FirebaseDatabase.getInstance().getReference("Admin")
    ref.addValueEventListener(object: ValueEventListener {

        override fun onCancelled(p0: DatabaseError) {
            Log.e("AdminActivity","cancelled")
        }

        override fun onDataChange(p0: DataSnapshot) {
            val uid = FirebaseAuth.getInstance().uid

            p0.child(uid!!).children.forEach{

                it.children.forEach{

                val posts = ArrayList<perizinan>()

                for (snapshot in it.children) {
                    val post = snapshot.getValue(perizinan::class.java)
                    posts.add(post!!)
                }

                    RecyclerViewAdmin.layoutManager = LinearLayoutManager(this@AdminActivity)
                    RecyclerViewAdmin.adapter = adminAdapter(izin(posts), this@AdminActivity)

                }
            }


        }
    })

}

下面是我的数据库结构：

Answer 1

您收到该错误是因为您在尝试从数据库中获取 perizinan 对象时使用了错误的引用。要解决这个问题，请更改以下代码行：

val ref= FirebaseDatabase.getInstance().getReference("Admin")

到

val ref= FirebaseDatabase.getInstance().getReference()
    .child("Admin")
    .child(FirebaseAuth.getInstance().uid)
    .child(senderId)

和

p0.child(uid!!).children.forEach{ /* ... */ }

到

p0.children.forEach{ /* ... */ }