问机器人科特林。利用碎片进行回收查看的数据库问题

EN

<androidx.recyclerview.widget.RecyclerView
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_marginTop="8dp"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            android:layout_marginStart="8dp"
            android:layout_marginBottom="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            android:layout_marginEnd="8dp"
            android:id="@+id/job_recyclerView"/>

data class JobData(val companyName: String, val location: String)

class CustomAdapter(val userList: ArrayList<JobData>) : RecyclerView.Adapter<CustomAdapter.ViewHolder>() {

//Returning view for each item in the list
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CustomAdapter.ViewHolder {
    val v = LayoutInflater.from(parent.context).inflate(R.layout.job_item_layout, parent, false)
    return ViewHolder(v)
}

//Binding the data on the list
override fun onBindViewHolder(holder: CustomAdapter.ViewHolder, position: Int) {
    holder.bindItems(userList[position])
}

override fun getItemCount(): Int {
    return userList.size
}

//Class holds the job list view
class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

    fun bindItems(job: JobData) {
        val textViewName = itemView.findViewById(R.id.tv_company_name) as TextView
        val textViewAddress  = itemView.findViewById(R.id.tv_Location) as TextView
        textViewName.text = job.companyName
        textViewAddress.text = job.location
    }
}
}

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    val binding: FragmentMainBinding = DataBindingUtil.inflate(
        inflater, R.layout.fragment_main, container, false)

    //Setting onClickListener for FAB(floating action button) using Navigation
    binding.createNewJobFAB.setOnClickListener { v: View ->
        v.findNavController().navigate(R.id.action_mainFragment_to_createNewJobFragment)
    }

    //getting recyclerview from xml
    val recyclerView = findViewById(R.id.job_recyclerView) as RecyclerView

    //adding a layoutmanager
    recyclerView.layoutManager = LinearLayoutManager(this, RecyclerView.VERTICAL, false)


    //Arraylist to store jobs using the data class JobData
    val jobs = ArrayList<JobData>()

    //add dummy data to list
    jobs.add(JobData("A Company", "Town A"))
    jobs.add(JobData("B Company", "Town B"))
    jobs.add(JobData("C Company", "Town C"))
    jobs.add(JobData("D Company", "Town D"))

    //creating adapter
    val adapter = CustomAdapter(jobs)

    //add adapter to recyclerView
    recyclerView.adapter = adapter
    return binding.root
}
}

class MainActivity : AppCompatActivity() {

//private lateinit var binding: ActivityMainBinding

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    @Suppress("UNUSED_VARIABLE")
    val binding = DataBindingUtil.setContentView<ActivityMainBinding>(this, R.layout.activity_main)
}

//Ensures back button works as it should
override fun onSupportNavigateUp() = findNavController(this, R.id.navHostFragment).navigateUp()
}

android {
compileSdkVersion 28
dataBinding {
    enabled = true
}
...
}

kapt {
generateStubs = true
correctErrorTypes = true
}

dependencies {
...
kapt "com.android.databinding:compiler:$gradle_version"

...
}