I have fragment which showing weather for 10 days with getting geolocation city and show exactly weather for this city for 10 days.

I have problem initialization with RecyclerView and Viewmodel.

Also I use Hilt to provide dependencies.

My goal is showing weather by location (already have permission) for 10 days.

import androidx.lifecycle.LiveData
import dagger.hilt.android.lifecycle.HiltViewModel
import db.entities.WeatherData


@HiltViewModel
interface ForecastViewmodel {
val dataforecast:LiveData<List<WeatherData>>
val city : LiveData<String>
val isRefreshing:LiveData<Boolean>

fun onRefresh()
}

@HiltViewModel
class ForecastViewmodelImpl(private val repository: ForecastRepository,
                            private val day: Day

                            ) : ForecastViewmodel,
    ViewModel(){

    override val dataforecast = MutableLiveData<List<WeatherData>>()
    override val city = MutableLiveData(day.city)
    override val isRefreshing = MutableLiveData(true)


    init {
        loadForecast()
    }

    private fun loadForecast() {
        isRefreshing.value = true
        viewModelScope.launch {
            try {
                val data = repository.getForecast(day.days)
             Timber.d("size is ${data}")
            }catch (e:Exception){
Timber.e(e)
            }
            isRefreshing.value = false
        }
    }

    override fun onRefresh() = loadForecast()

    private fun Forecastday.toWeatherData() = WeatherData(
        date = date,
        temp = "${temp.roundToInt()}℃"
    )
}

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.example.testtaskweatherappkevychsol.R
import db.entities.WeatherData

class WeatherRecView:RecyclerView.Adapter<WeatherRecView.WeatherHolder>() {
    var listweather = emptyList<WeatherData>()
    class WeatherHolder(view:View):RecyclerView.ViewHolder(view)

    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): WeatherHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.daily_weather_layout,
            parent,false)
        return WeatherHolder(view)
    }

    override fun onBindViewHolder(
        holder: WeatherHolder,
        position: Int
    ) {
       holder.itemView.findViewById<TextView>(R.id.Dateitem).text = listweather[position].date
        holder.itemView.findViewById<TextView>(R.id.tempitem).text = listweather[position]
            .temp.toString()
    }

    override fun getItemCount(): Int {
       return listweather.size
    }
    fun addlistintoUI(list: List<WeatherData>){
        listweather = list

    }
}

data class WeatherData(
    val temp:String,
    val date:String
)

import RecyclerView.WeatherRecView
import Viewmodel.ForecastViewmodel
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.recyclerview.widget.DividerItemDecoration
import androidx.recyclerview.widget.LinearLayoutManager
import com.example.testtaskweatherappkevychsol.R
import com.example.testtaskweatherappkevychsol.databinding.FragmentWeatherBinding
import dagger.hilt.android.AndroidEntryPoint


@AndroidEntryPoint
class WeatherAtTheLifeMomentFragment : Fragment(R.layout.fragment_weather){
    lateinit var recview:WeatherRecView
  private var binding : FragmentWeatherBinding? = null
 lateinit var  viewmodel:ForecastViewmodel




    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val binding = FragmentWeatherBinding.inflate(inflater,container,false)
        this.binding = binding
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
with(binding){
    this!!.refreshbt.setOnClickListener { viewmodel.isRefreshing }
    containerlistweather.adapter = recview
   containerlistweather.addItemDecoration(DividerItemDecoration(containerlistweather.context,
        (containerlistweather
       .layoutManager as LinearLayoutManager).orientation))

    with(viewmodel){
dataforecast.observe(viewLifecycleOwner) { recview.listweather = it }
       City.text = city.toString()
    }
}
    }

    override fun onDestroyView() {
        super.onDestroyView()
        binding = null
    }
}

CodePudding user response：

lateinit property recview has not been initialized

you are getting this issue as you are trying to access lateinit property recview without initialising it

in WeatherAtTheLifeMomentFragment

From

containerlistweather.adapter = recview

To

recview = WeatherRecView() // initialise recview variable by creating instance of your adapter
containerlistweather.layoutManager = LinearLayoutManager(context) // not sure you have set layout manager in your xml so just adding it in your code as it is necessary to use
containerlistweather.adapter = recview

Also you have create method addlistintoUI in WeatherRecView class so use it and make below mentioned changes to load your data

in WeatherAtTheLifeMomentFragment class

From

dataforecast.observe(viewLifecycleOwner) { recview.listweather = it }

To

dataforecast.observe(viewLifecycleOwner) { recview.addlistintoUI(it) }

in WeatherRecView class

From

fun addlistintoUI(list: List<WeatherData>){
        listweather = list

    }

To

fun addlistintoUI(list: List<WeatherData>){
        listweather.addAll(list)
        notifyDataSetChanged()

    }
    ```