【发布时间】：2022-01-21 22:49:12
【问题描述】：
class FeedRecyclerAdapter (private val postList : ArrayList<Post>) : RecyclerView.Adapter<FeedRecyclerAdapter.PostHolder>() {
class PostHolder(val binding: FragmentDataBinding) : RecyclerView.ViewHolder(binding.root)
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PostHolder {
val binding = FragmentDataBinding.inflate(LayoutInflater.from(parent.context),parent,false)
return PostHolder(binding)
}
override fun onBindViewHolder(holder: PostHolder, position: Int) {
holder.binding.verimText.text = postList.get(position).lsi
}
override fun getItemCount(): Int {
return postList.size
}
这是为 recyclerView 编写的代码。
private lateinit var firestore: FirebaseFirestore
private lateinit var auth: FirebaseAuth
private var _binding: FragmentDataBinding? = null
private val binding get() = _binding!!
private lateinit var postArrayList : ArrayList<Post>
private lateinit var feedAdapter : FeedRecyclerAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
auth = Firebase.auth
firestore = Firebase.firestore
postArrayList = ArrayList<Post>()
feedAdapter = FeedRecyclerAdapter(postArrayList)
getData()
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
_binding = FragmentDataBinding.inflate(inflater, container, false)
val view = binding.root
return view
}
private fun getData(){
firestore.collection("Posts").addSnapshotListener { value, error ->
if (error!=null){
Toast.makeText(requireContext(),error.localizedMessage,Toast.LENGTH_SHORT).show()
}else{
if (value !=null){
if (!value.isEmpty){
val documents = value.documents
for (document in documents){
val araziBoyutu = document.get("Arazi Boyutu") as String
val araziEgimi = document.get("Arazi Eğimi") as String
val panelBoyutu = document.get("Panel Boyutu") as String
val panelSayisi = document.get("Panel Sayisi") as String
val sehir = document.get("Şehir") as String
val post = Post(panelSayisi,panelBoyutu,araziEgimi,araziBoyutu,sehir)
postArrayList.add(post)
recyclerView.adapter = FeedRecyclerAdapter(postArrayList)
}
feedAdapter.notifyDataSetChanged()
}
}
}
}
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding.recyclerView.adapter = feedAdapter
recyclerView.layoutManager = LinearLayoutManager(activity)
这里的代码是我定义 RecyclerView 并保存信息的部分。
我可以拉取数据，我可以在firebase上看到我正在尝试打印的 verimText TextView 中的这些数据。
【问题讨论】：
-
您得到的确切错误是什么？
-
尝试在空对象引用上调用虚拟方法 'void androidx.recyclerview.widget.RecyclerView.setAdapter(androidx.recyclerview.widget.RecyclerView$Adapter)'
-
您在代码中的哪个位置设置了适配器？请分享该代码。
-
我解决了这个问题。但现在还有另一个问题。我能够显示我保存在 verimText 中的数据。我用 println 命令调试，我可以看到我在 logcat 上输入的数据。但是有一个问题。 Firebase 总是在 verimText 上写入我输入的第一个值，而不是在 firestore 中注册的最后一个值。
-
我更新了第 2 部分的代码。现在我的位置应用程序中的所有代码都是这样的。
标签： android firebase kotlin fragment