我在 MainAcitvity 连接到 ViewModel 和 Adapter 时遇到了什么问题？

Question

I am trying to show list of elements in Recyclerview from Adapter class while connecting it function in ViewModel class. i am using mvvm architecture, when I execute the program, I am getting 'java.lang.RuntimeException: Cannot create an instance of class com.example.mvvmnetwork.viewmodel.Mainviewmodel' error in my Logcat, I am providing the Logcat below.

MainActivity.kt

    import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.ProgressBar
import androidx.activity.viewModels
import androidx.core.view.isVisible
import androidx.lifecycle.ViewModelProvider
import androidx.recyclerview.widget.DividerItemDecoration
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.example.mvvmnetwork.adapter.MainAdapter
import com.example.mvvmnetwork.viewmodel.Mainviewmodel

class MainActivity : AppCompatActivity() {

   private val mainViewmodel:Mainviewmodel by viewModels()
    lateinit var mainAdapter: MainAdapter
    lateinit var recyclerView: RecyclerView
    lateinit var progressBar:ProgressBar

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        recyclerView = findViewById<RecyclerView>(R.id.recyclerView)
        progressBar = findViewById<ProgressBar>(R.id.progressBar)

        setupAdapter()
        setupObserver()

    }

    private fun setupObserver() {

        mainViewmodel.response.observe(this){ results ->
            results.data?.let { users->
                progressBar.isVisible = users.isEmpty()
                recyclerView.isVisible = users.isNotEmpty()
                mainAdapter.addData(users)

            }

        }
        mainViewmodel.getUsers()
    }

    

    private fun setupAdapter() {

        recyclerView.layoutManager = LinearLayoutManager(this)
        mainAdapter = MainAdapter(arrayListOf())
        recyclerView.addItemDecoration(
            DividerItemDecoration(
            recyclerView.context,
            (recyclerView.layoutManager as LinearLayoutManager).orientation
        )
        )
        recyclerView.adapter = mainAdapter
    }




}

MainAdapter.kt[Adapter class]

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import androidx.appcompat.widget.AppCompatTextView
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.RecyclerView
import com.bumptech.glide.Glide
import com.example.mvvmnetwork.R
import com.example.mvvmnetwork.data.api.User

class MainAdapter(private val users:
                  ArrayList<User>):RecyclerView.Adapter<MainAdapter.DataViewHolder>() {

   inner class DataViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        fun bind(user: User) {
            val imageView:ImageView = itemView.findViewById(R.id.imageViewAvatar)
            val textViewUserName:AppCompatTextView = itemView.findViewById(R.id.textViewUserName)
            val textViewUserEmail:AppCompatTextView = itemView.findViewById(R.id.textViewUserEmail)
            Glide.with(imageView.context)
                .load(user.avatar)
                .into(imageView)

            textViewUserName.text = user.name
            textViewUserEmail.text=user.email
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int)=
        DataViewHolder(
            LayoutInflater.from(parent.context).inflate(
                R.layout.item_layout, parent,
                false
        )
        )

    override fun onBindViewHolder(holder: DataViewHolder, position: Int)= holder.bind(users[position])

    override fun getItemCount(): Int =users.size

     fun addData(list: List<User>){
         users.addAll(list)
     }


}

MainviewModel.kt [Viewmodel class]

import androidx.lifecycle.*
import com.example.mvvmnetwork.data.api.User
import com.example.mvvmnetwork.repository.UserRepository
import com.example.mvvmnetwork.sealed.Network
import dagger.hilt.android.lifecycle.HiltViewModel
import kotlinx.coroutines.flow.collect
import kotlinx.coroutines.launch
import javax.inject.Inject

@HiltViewModel
class Mainviewmodel @Inject internal constructor(private val userRepository: UserRepository,
      ):ViewModel() {

          private val _response:MutableLiveData<Network<List<User>>> = MutableLiveData()

          val response:LiveData<Network<List<User>>> = _response


    fun getUsers() = viewModelScope.launch {

        userRepository.getUsers().collect {

            _response.value = it
        }
    }



}

Logcat

Answer 1

你错过了在你的活动中注释

@AndroidEntryPoint