Error after Listing 9.3

Android Programming (4th Edition) 9. Displaying Lists with RecyclerView
1

Hi

if I start CriminalIntent after Listing 9.3 the emulator says Criminal Intent keeps stopping

Logcat says

at com.bignerdranch.android.criminalintent.CrimeListFragment.getCrimeListViewModel(Unknown Source:2)
at com.bignerdranch.android.criminalintent.CrimeListFragment.access$getCrimeListViewModel$p(CrimeListFragment.kt:9)
at com.bignerdranch.android.criminalintent.CrimeListFragment$crimeListViewModel$2.invoke(CrimeListFragment.kt:12)
at com.bignerdranch.android.criminalintent.CrimeListFragment$crimeListViewModel$2.invoke(CrimeListFragment.kt:9)

What should I do?

2

Changing

implementation 'com.android.support:appcompat-v7:28.0.0'

to

implementation ‘androidx.appcompat:appcompat:1.0.2’

doesn’t help

other lines are

implementation “androidx.fragment:fragment-ktx:$fragment_version”
implementation “androidx.lifecycle:lifecycle-extensions:2.0.0”
implementation “androidx.recyclerview:recyclerview:1.0.0”

Any suggestions?

3

Listing of CrimeListFragment

package com.bignerdranch.android.criminalintent

import android.os.Bundle
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.lifecycle.ViewModelProviders
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView

private const val TAG =“CrimeListFragment”

class CrimeListFragment : Fragment() {

private lateinit var crimeRecyclerView :RecyclerView

private val crimeListViewModel : CrimeListViewModel by lazy{
    ViewModelProviders.of(this).get(crimeListViewModel::class.java)

}
override fun onCreate(savedInstanceState: Bundle?){
    super.onCreate(savedInstanceState)
    Log.d(TAG, "Total crimes: ${crimeListViewModel.crimes.size}")
}

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    val view =inflater.inflate(R.layout.fragment_crime_list,container,false)
    crimeRecyclerView =view.findViewById(R.id.crime_recycler_view) as RecyclerView
    crimeRecyclerView.layoutManager=LinearLayoutManager(context)
    return view
}

private inner class CrimeHolder(view: View)
    :RecyclerView.ViewHolder(view)
{
        val titleTextView: TextView = itemView.findViewById(R.id.crime_title)
    val dateTextView: TextView = itemView.findViewById(R.id.crime_date)
    }

private inner class CrimeAdapter(var crimes: List<Crime>)
    : RecyclerView.Adapter<CrimeHolder>(){

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int)
        : CrimeHolder{val view = layoutInflater.inflate(R.layout.list_item_crime, parent,false)
        return CrimeHolder(view)



        }
    override fun getItemCount() = crimes.size

    override fun onBindViewHolder(holder: CrimeHolder, position: Int) {
        val crime = crimes[position]
        holder.apply { titleTextView.text = crime.title
            dateTextView.text=crime.date.toString()}
    }
    }


companion object{
    fun newInstance():CrimeListFragment{
        return CrimeListFragment()
    }



}

}
4

@HothCoder were you able to resolve this? If not please post the full stack trace from Logcat.