ViewModel中的Kotlin单例吸气剂

Question

I'm studying Android Architecture Components. How to implement singleton getInstance() method using Kotlin ? I did this using Java-like style (getLocation), but it is not kotlin-like.

class LocationViewModel: ViewModel() {
        lateinit var locationData: MyLocationListener

        fun getLocation(context: Context): MyLocationListener {
            locationData = MyLocationListener(context)
            return locationData
        }
    }

Answer 1

You shouldn't really use a make ViewModels a singleton - they should be scoped to the lifecycle of the Activity/Fragment in which they are created.

If you want to expose the MyLocationListener instance you could use the AndroidViewModel class - this provides you with access to the application class which you can use as the Context.

class LocationViewModel(application: Application): AndroidViewModel(application) {
    val locationData = MyLocationListener(application)
}