My recyclerview doesn't udpate with the livedata when I remove an
item.
The function jokeisclicked() opens up a dialog for the user which
can choose to edit or delete an item of the room database.
The delete completes, but only when I refresh the tab. How can I complete the delete without refreshing the tab?
class DashboardFragment : Fragment() {
private lateinit var dashboardViewModel: DashboardViewModel
lateinit var binding: FragmentDashboardBinding
lateinit var adapter: JokeRecyclerViewAdapter
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
//init repo and viewmodel
val dao: JokeDao = RoomDB.getInstance(requireContext()).JokeDAO
val jokerepo = JokeRepo(dao, RetrofitBuilder.jokeservice)
val factory = DashboardViewModelFactory(jokerepo)
dashboardViewModel = ViewModelProvider(this, factory).get(DashboardViewModel::class.java)
//init binding
binding = FragmentDashboardBinding.inflate(inflater, container, false)
binding.lifecycleOwner = this
//recycler observe from livedata
dashboardViewModel.jokes.observe(viewLifecycleOwner, {
binding.recyclerview.layoutManager = LinearLayoutManager(this.requireContext())
adapter = JokeRecyclerViewAdapter(it, { selected: Joke -> jokeIsClicked(selected) })
binding.recyclerview.adapter = adapter
})
return binding.root
}
fun jokeIsClicked(joke: Joke) {
//show pop up dialog
val dialog = PopUpFragment(joke)
getFragmentManager()?.let { dialog.show(it, "popUpDialog") }
}
}
here is the popupfragment class
class PopUpFragment(private val selectedJoke : Joke) : DialogFragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
//init viewmodel
val dao = RoomDB.getInstance(this.requireContext()).JokeDAO
val jokerepo = JokeRepo(dao,RetrofitBuilder.jokeservice)
val factory = PopUpViewModelFactory(jokerepo)
val popupViewModel : PopUpFragmentViewModel = ViewModelProvider(this,factory).get(PopUpFragmentViewModel::class.java)
//init binding
val binding = FragmentPopUpBinding.inflate(inflater,container,false)
//edit clicked
binding.editjoke.setOnClickListener{
}
//delete clicked
binding.deletejoke.setOnClickListener {
//TODO
popupViewModel.deleteJoke(selectedJoke)
this.dismiss()
}
return binding.root
}
}
I think you dont update value of livedata at viewModel. Could you share viewmodles also ? If dialogViewModel removes joke from database than you have to return at #Dao's method LiveData or Flow.
Any way don't set adapert and layout manager at observe method - it's point less. For updating list at adaper you could create method and call in it notifiDataSetChanged() or (the best way of handling changes at adaper) diffUtils.
You'll need to do 2 things:
1 - Remove the data from your variable i.e if you're storying it within a an array then use array = ArrayUtils.remove(array, index);
2 - run .notifyDataSetChanged() on your RecyclerView's Adapter in order refresh the view based on the values of the new data set.
Related
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val view = inflater.inflate(R.layout.fragment_list, container, false)
val recyclerView = view.findViewById<RecyclerView>(R.id.recyclerView)
recyclerView.adapter = adapter
recyclerView.layoutManager = LinearLayoutManager(requireActivity())
noDataTextView = view.findViewById(R.id.no_data_textView)
noDataImageView = view.findViewById(R.id.no_data_imageView)
mToDoViewModel.getAllData.observe(viewLifecycleOwner, Observer { data ->
adapter.setData(data)
mSharedViewModel.checkIfDatabaseEmpty(data)
})
floatingActionButton = view.findViewById<FloatingActionButton>(R.id.floatingActionButton)
listLayout = view.findViewById(R.id.listLayout)
floatingActionButton.setOnClickListener {
findNavController().navigate(R.id.action_listFragment_to_addFragment)
}
//set menu
setHasOptionsMenu(true)
mSharedViewModel.emptyDatabase.observe(viewLifecycleOwner, Observer { data ->
showEmptyDatabaseViews(data)
})
return view
}
I have a visibility system going on where if the database is empty then the image is shown.
but when I run the code first image shows up then the data shows up then I debugged it and seen that mSharedViewModel.emptyDatabase.observe() function is running first? what is the main issue here,
ps, I am using suspended fun to load the data
Edit 1:
my default visibility is invisible
<ImageView>
.
.
android:visibility="invisible"
this is my ShareViewModel Class Which will check the database empty or not
class SharedViewModel(application: Application) : AndroidViewModel(application) {
val emptyDatabase: MutableLiveData<Boolean> = MutableLiveData(true)
fun checkIfDatabaseEmpty(toDoData: List<ToDoData>){
emptyDatabase.value=toDoData.isEmpty()
}
and this my ViewModel
class ToDoViewModel(application: Application):AndroidViewModel(application) {
private val toDoDao= ToDoDatabase.getDatabase(application).ToDoDao()
private val repository:ToDoRepository
val getAllData: LiveData<List<ToDoData>>
init {
repository=ToDoRepository(toDoDao)
getAllData=repository.getAllData
}
Your expectation:
I have a visibility system going on where if the database is empty then the image is shown.
According to your code:
android:visibility="invisible"
The default visibility is invisible okay but check the view model code
val emptyDatabase: MutableLiveData<Boolean> = MutableLiveData(true)
You set the value to true. So when any observer start observing the changes, the default value will be passed to the observer, so logically your code is OK, database is empty and image view is visible.
So, you should set false as the default value.
Is there a more generic way to init this two initialization lines?
private var _binding: MyFragmentViewBinding? = null
private val binding get() = _binding!!
Should we call every time binding
binding.cancelButton.setOnClickListener { }
binding.homeButton.setOnClickListener { }
binding.aboutButton.setOnClickListener { }
Or to create class variable?
cancelButton = binding.cancelButton
binding.cancelButton.setOnClickListener{}
And, should we set binding = null in adapter?
I think it is more of a personal preference. I like to do it with extension and higher-order function
fun <T : ViewDataBinding> Fragment.getDataBinding(layout: Int, container: ViewGroup?): T {
val binding: T = DataBindingUtil.inflate(layoutInflater, layout, container, false)
binding.lifecycleOwner = viewLifecycleOwner
return binding
}
My Fragment looks like this.
class InviteFragment : Fragment() {
private lateinit var binding: FragmentInviteBinding
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
binding = getDataBinding(R.layout.fragment_invite, container)
return binding.apply {
inviteAll.setOnClickListener(onInviteAllClick)
// You can set as many click listener here
// or some initialization related to view such as
// setting up recycler view adapter and decorators
}.root
}
private val onInviteAllClick = View.OnClickListener {
// Invite users
}
}
By doing things like this your onCreateView will be more readable and never going to get very long.
I have a tablayout inside a fragment. The tab layout has 3 tabs. Which tab has a fragment.
And, in the first fragment I insert a string and add it to a viewModel MutableLiveData<ArrayList>> variable.
Then, I want to observe in the third fragment.
My main ViewModel:
class MainViewModel : ViewModel() {
val message = MutableLiveData<ArrayList<String>>(arrayListOf())
fun myMessage(msg: String) {
message.value?.add(msg)
}
}
Third Fragment:
class Fragment3 : Fragment() {
lateinit var model: MainViewModel
private lateinit var viewModel: MainViewModel
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view= inflater.inflate(R.layout.fragment3_fragment, container, false)
model = activity?.let { ViewModelProvider(it).get(MainViewModel::class.java) }!!
model.message.observe(viewLifecycleOwner, Observer {
Log.e("aqui", "aqui$it")
})
return view
}
}
My first Fragment:
class Fragment1 : Fragment() {
lateinit var model: MainViewModel
private lateinit var viewModel: MainViewModel
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view= inflater.inflate(R.layout.fragment1_fragment, container, false)
model = activity?.let { ViewModelProvider(it).get(MainViewModel::class.java) }!!
var btnTest= view.findViewById<Button>(R.id.btn_test)
btnTest.setOnClickListener {
model.myMessage(et_text.text.toString())
}
return view
}
}
When I open the Third fragment it observes as planned. When I come back to first Fragment and add more Strings to the array list, the third does not observes again, I don't know why.
First Observer:
My layout:
My observer only observes once.
You have to change the value of the live data instead of just adding an item to the already set list.
Change your function myMessage as:
fun myMessage(msg: String) {
val list = message.value
list.add(msg)
message.value = list
}
This will take your existing list then add your new item and then set the value of the live data so that the observe will be called.
Inside my fragment, i have some image and views that are getting their values by binding data, and beneath them a RecyclerView. The images and textviews are showing successfully but my Recyclerview won't show. If i return my view only, the RecyclerView shows but the binded data doesn't. I want to view both of them.
[]
class DetailFragment : Fragment(), LessonRecyclerAdapter.LessonItemListener {
private lateinit var viewModel: SharedViewModel
private lateinit var recyclerView: RecyclerView
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_detail, container, false)
recyclerView = view.findViewById(R.id.lessonRecyclerView)
navController = Navigation.findNavController(requireActivity(), R.id.nav_host )
viewModel = ViewModelProvider(requireActivity()).get(SharedViewModel::class.java)
viewModel.lessonData.observe(viewLifecycleOwner, Observer {
val adapter =
LessonRecyclerAdapter(
it,
this
)
recyclerView.adapter = adapter
})
// return binding data
val binding = FragmentDetailBinding.inflate(inflater, container, false)
binding.lifecycleOwner = this
binding.viewModel = viewModel
return binding.root
//return view
}
As you can see, There are two inflates, one for binding and another for view(for recyclerview setup). The easy solution is to directly use recyclerview from binding variable to set up the list as:
private lateinit var binding: FragmentDetailBinding
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
navController = Navigation.findNavController(requireActivity(), R.id.nav_host )
viewModel = ViewModelProvider(requireActivity()).get(SharedViewModel::class.java)
binding = FragmentDetailBinding.inflate(inflater, container, false)
binding.lifecycleOwner = this
binding.viewModel = viewModel
viewModel.lessonData.observe(viewLifecycleOwner, Observer {
val adapter =
LessonRecyclerAdapter(
it,
this
)
// directly access the view using ids
binding.lessonRecyclerView.adapter = adapter
})
return binding.root
}
Another option is to use binding adapters with live data to setup adapter and pass the data to the adapter.
I currently have an interface that's implemented in the MainActivity that allows communication with the NumberFragment. The onCountClicked is the method in NumberFragment receiving the id of the item click.
Question
How can I send the onCountClicked position to the NumberFragmentViewModel every time an item is clicked?
Note: Using databinding & recycleview
Main Activity
val newFragment = NumberFragment()
val args = Bundle()
args.putInt(NumberFragment().onCountClicked(data).toString(),data.toInt())
newFragment.arguments = args
Number Fragment
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
val sleepTrackerViewModel =
ViewModelProviders.of(
this, viewModelFactory).get(NumberViewModel::class.java)
setHasOptionsMenu(true)
binding.setLifecycleOwner(this)
binding.sleepTrackerViewModel = sleepTrackerViewModel
//Observes for any changes on database and updates the UI
sleepTrackerViewModel.dbCount.observe(this, Observer {dbCount ->
dbView.text = dbCount.number.toString()
})
return binding.root
}
fun onCountClicked(position: Long) {
Log.i("NumberF" , "------------->" + position)
}
You can just simply create a method in the viewModel that receives that position and updates the value of the live data. I would do it like this:
private val _idItemClicked = MutableLiveData<Int>()
val idItemClicked: LiveData<Int> = _idItemClicked
fun setIdItemClicked(id: Int) {
_idItemClicked.value = id
}
Now you call the function setIdItemClicked to set a new value.