LiveData and Coroutines - Property must be initialized or abstract

Question

I am trying to use LiveData and Coroutines together in MVVM, and I may be missing something simple.

class WeatherViewModel (
    private val weatherRepository: ForecastRepository
) : ViewModel() {

    var weather: LiveData<Weather>;

    /**
     * Cancel all coroutines when the ViewModel is cleared.
     */
    @ExperimentalCoroutinesApi
    override fun onCleared() {
        super.onCleared()
        viewModelScope.cancel()
    }


    init {
        viewModelScope.launch {
            weather = weatherRepository.getWeather()
        }

    }

}

But I am getting Property must be initialized or be abstract on assigning the weather in the init function. I am assuming this is the case because I am using coroutines viewModelScope.launch.

override suspend fun getWeather(): LiveData<Weather> {
    return withContext(IO){
       initWeatherData()
       return@withContext weatherDao.getWeather()
    }
}

How do I fix this?

Answer 1

You can declare weather property as lateinit:

private lateinit var weather: LiveData<String>

Or make it nullable:

private var weather: LiveData<String>? = null

If you're sure that the property will be initialized before you first use it use lateinit otherwise make it nullable.