I'm building an app around a Meals API. First a list of categories will be shown. On selecting a category, meals of the particular category will be displayed. Users can add any meal to favorites. User can see the list of favorites by clicking on the favorites icon at the top. If a user clicks a meal, he gets to see the details of the recipe for that meal. I'm using the same fragment & viewmodel to display the meals based on the category and also the favorite meals. I'm using MVVM with MutableLiveData. The favorites icon is in the activity and I keep on replacing the fragments within the activity.
If I click on the favorites icon from the CategoriesFragment or the FilterByTypeFragment, all the meals added to the favorites are shown correctly. But if I click on the favorites icon when I'm in the RecipeDetailsFragment, it just displays all the meals of that category. That means, it just works like a back press on the RecipeDetailsFragment. When I debug, I see that the fetchFavorites method is being called in the viewmodel when I click on the favorites icon. But what the observer gets at the end is the list of all the meals of the selected category. Why don't I see only the list of favorites when I navigate from RecipeDetailsFragment to the favorites section? I'm posting the code below for your understanding:
@HiltViewModel
class FilterByCategoryViewModel @Inject constructor(
val dataManager: AppDataManager,
val networkHelper: NetworkHelper,
val category: String?,
val isFavorites: String = "N"
) : ViewModel() {
val _meals = MutableLiveData<Resource<MealsResponse>>()
init {
if (isFavorites.equals("Y")) fetchFavorites()
else fetchMealsByCategory(category)
}
fun fetchMealsByCategory(category: String?) {
viewModelScope.launch {
_meals.postValue(Resource.loading(null))
if (networkHelper.isNetworkConnected()) {
launch(Dispatchers.IO) {
dataManager.getMealsByCategory(category!!).let {
if (it.isSuccessful) {
_meals.postValue(Resource.success(it.body()))
} else _meals.postValue(
Resource.error(
it.errorBody().toString(),
null
)
)
}
}
} else _meals.postValue(Resource.error("No Internet Connection", null))
}
}
fun fetchFavorites() {
viewModelScope.launch {
_meals.postValue(Resource.loading(null))
if (networkHelper.isNetworkConnected()) {
launch(Dispatchers.IO) {
dataManager.getFavoriteMeals().let {
if (it.isSuccessful) {
println("Body: " + it.body().toString())
_meals.postValue(Resource.success(it.body()))
println(_meals.getValue().toString())
} else _meals.postValue(
Resource.error(
it.errorBody().toString(),
null
)
)
}
}
} else _meals.postValue(Resource.error("No Internet Connection", null))
}
}
fun onFavoriteClicked(meal: Meal) {
viewModelScope.launch {
val job = launch(Dispatchers.IO) {
val isFavorite = dataManager.isFavorite(meal)
val _meal = meal.copy(
isFavorite = when (isFavorite) {
1 -> 0
else -> 1
}
)
dataManager.setFavorite(_meal)
}
job.join()
if (isFavorites.equals("Y"))
fetchFavorites()
else
fetchMealsByCategory(category)
}
}
}
The Fragment:
@AndroidEntryPoint
class FilterByTypeFragment : Fragment(), MealAdapter.FavoriteClickListener {
@Inject
lateinit var dataManager: AppDataManager
@Inject
lateinit var networkHelper: NetworkHelper
private lateinit var adapter: MealAdapter
private lateinit var binding: FragmentCategoriesBinding
private var category: String? = null
private var isFavorites: String = "N"
lateinit private var filterByCategoryViewModel: FilterByCategoryViewModel
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
binding = DataBindingUtil.inflate<FragmentCategoriesBinding>(
inflater,
R.layout.fragment_categories, container, false
)
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
val controller: NavController = Navigation.findNavController(view!!)
controller.popBackStack(R.id.recipeDetailFragment, true)
if (arguments != null) {
category = FilterByTypeFragmentArgs.fromBundle(requireArguments()).category
isFavorites = FilterByTypeFragmentArgs.fromBundle(requireArguments()).isFavorites
}
setupUI()
}
private fun setupUI() {
binding.recyclerView.layoutManager = GridLayoutManager(activity, 2)
adapter = MealAdapter(arrayListOf(), this)
binding.recyclerView.addItemDecoration(
GridSpacingItemDecoration(true, 2, 20, true)
)
binding.recyclerView.adapter = adapter
}
override fun onResume() {
super.onResume()
val factory = FilterByTypeViewModelFactory(dataManager, networkHelper, category, isFavorites)
filterByCategoryViewModel = ViewModelProvider(
this,
factory
).get(FilterByCategoryViewModel::class.java)
setupObserver()
}
private fun setupObserver() {
filterByCategoryViewModel._meals.observe(this, Observer {
when (it.status) {
Status.SUCCESS -> {
binding.progressBar.visibility = View.GONE
it.data?.let { users ->
renderList(users.meals)
}
binding.recyclerView.visibility = View.VISIBLE
}
Status.LOADING -> {
binding.progressBar.visibility = View.VISIBLE
binding.recyclerView.visibility = View.GONE
}
Status.ERROR -> {
//Handle Error
binding.progressBar.visibility = View.GONE
Toast.makeText(activity, it.message, Toast.LENGTH_LONG).show()
}
}
})
}
private fun renderList(meals: List<Meal>) {
println("Meals: " + meals.toString())
adapter.clearData()
adapter.addData(meals)
adapter.notifyDataSetChanged()
}
override fun onFavoriteClick(meal: Meal) {
filterByCategoryViewModel.onFavoriteClicked(meal)
}
}
