This is what I'm trying to do.
ArrayList
of object inside a Fragment FragmentActivity
container (the activity that hosts all the fragments)So, What I have done is the following.
First I created the SharedViewModel
from where I will set and get the data from :
class SharedViewModel: ViewModel() {
var personArrayObj:MutableLiveData<ArrayList<Person>> = MutableLiveData()
fun setPersonArray(personArray:ArrayList<Person>){
personArrayObj.value = personArray
}
val getPersonArray:LiveData<ArrayList<Person>>
get() = personArrayObj
}
Now , I instantiate this ViewModel
inside the MainActivity
that hosts all the fragments creation, so , I can get the ArrayData
from wherever Fragment its set :
class MainActivity: FragmentActivity(){
private lateinit var viewModel:SharedViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
viewModel = ViewModelProviders.of(this).get(SharedViewModel::class.java)
viewModel.getPersonArray.observe(this, Observer { it:ArrayList<Person>
Log.d("Array:",""+it)
})
}
}
Then the last thing I need to do is to set the value of that Array from whatever Fragment I want, and then the host Activity will be triggered if the value has changed, so, to do this, I simple do a viewModel.setValue(personArray)
at my desired Fragment .
When I try to instantiate the SharedViewModel
inside any fragment I get this problem :
I tried to assert !! for the null, use let too, but is not working and I wonder from where it comes that FragmentActivity
required
If I use viewLifecycleOwner
instead of activity
it says to me that it cant be called either with Fragment or FragmentActivity ?
Any clues?
Thanks .
Fragments offer a helper method for retrieving a non-null Activity - requireActivity()
. Use that instead of activity
:
viewModel = ViewModelProviders.of(requireActivity()).get(SharedViewModel::class.java)
As an alternative, you can include the fragment-ktx
dependency in your app and use the by activityViewModels() Kotlin property extension instead of using ViewModelProviders.of()
at all:
val viewModel: SharedViewModel by activityViewModels()