Im working on a project and implementing the MVVM model with databinding
and navigation
. My button
is on a fragment
that opens with a drawer menu item
, the thing is when i click on the button it does nothing, the debugger doesn't go into the navigate method, I really don't know what I did wrong, can someone help?
MYACCOUNT CLASS
:
class MyAccountFragment : BaseFragment() {
private val vm: MyAccountViewModel by viewModel()
override fun getViewModel(): BaseViewModel = vm
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val binding = FragmentMyAccountBinding.inflate(inflater, container, false)
context ?: return binding.root
injectFeature()
setToolbar(binding)
subscribeUi(binding)
return binding.root
}
/**
* set toolbar
* **/
private fun setToolbar(binding: FragmentMyAccountBinding) {
binding.appBarLayout.backClickListener = (activity as MainActivity).createOnBackClickListener()
}
/**
* set ui
* **/
private fun subscribeUi(binding: FragmentMyAccountBinding) {
binding.viewModel = vm
}
}
MYACCVIEWMODEL
class MyAccountViewModel constructor() : BaseViewModel() {
fun onAddRoomClick()
{
navigate(MyAccountFragmentDirections.actionMyAccountFragmentToAddRoomFragment())
}
}
and in the xml i implemented the
android:onClick="@{() -> viewModel.onAddRoomClick()}"
Im using this pattern for all my Fragments
and ViewModels
, and i really dont know why it doesn't do anything, the vm initializes. On the other drawermenu fragment
I also have the onClick method and it navigates to the other fragment. So if anyone knows the solution that would be helpful, thank you in advance.
the answer was in the initialization of the viewModel.
the onClick method in xml is in a content_layout that is included in a fragment_layout and instead of binding.viewModel = vm I had to do binding.content_layout.viewModel = vm.
private fun subscribeUi(binding: FragmentMyAccountBinding) {
binding.contentMyAccount.viewModel = vm
}
ViewModel is not supposed to handle any kind of navigation, it will just receive the event from the UI and pass it to the controller (which might be a fragment or activity) and the latter will handle the navigation...
So one way to solve your issue is to do the following:
ViewModel
class MyAccountViewModel constructor() : BaseViewModel() {
private val _navigateToRoomFragEvent = MutableLiveData<Boolean>(false)
val navigateToRoomFragEvent:LiveData<Boolean>
get()=_navigateToRoomFragEvent
fun onAddRoomClick()
{
_navigateToRoomFragEvent.value=true
}
fun resetNavigation(){
_navigateToRoomFragEvent.value=false
}
}
Controller (Activity or Fragment)
inside **onCreate() (if it is an activity)**
viewModel.navigateToRoomFragEvent.observe(this,Observer{navigate->
//boolean value
if(navigate){
navController.navigate(//action)
}
viewModel.resetNavigation() //don't forget to reset the event
})
onActivityCreated(if it is a fragment)
viewModel.navigateToRoomFragEvent.observe(viewLifeCycleOwner,Observer{navigate->
//boolean value
if(navigate){
navController.navigate(//action)
}
viewModel.resetNavigation() //don't forget to reset the event
})
Hope it helps,
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