Developing an android app is easy but developing an app with reusable components are the hardest thing, Some tools are helpful to write a code with prebuild tools and configuration.
This guideline will help set for setting MVVM architecture with different plugins.
Simple texView & Button sample using ViewModel, liveData and DataBinding
liveData countText in MainViewModel is incremented by 1 whenever INCREASE NUMBER is clicked.
//MainViewModel.class
fun clickIncreaseButton() {
_countText.value = "click count : ${++count}"
}Then countText is observed and will be notifed of updates whenever the value is changed.
viewModel.countText.observe(this, Observer { number ->
binding.textviewNumber.text = number
})Simple RecyclerView Sample using Retrofit, Koin, ViewModel. (PokeApi is used in this sample)
pokemon list is retreived using Retrofit and saved to liveData
//ListViewModel.class
private val _pokemonList = MutableLiveData<List<PokemonEntity>>()
val pokemonList: LiveData<List<PokemonEntity>> get() = _pokemonList
init {
viewModelScope.launch {
_pokemonList.postValue(getPokemonListUseCase.invoke())
}
}
fun addFavoritePokemon(pokemonEntity: PokemonEntity) = viewModelScope.launch {
setLocalPokemonUseCase(pokemonEntity)
}
}
then the list is observed and will be notifed of updates whenever the the list is retreived.
//ListAcitivty.class
viewModel.pokemonList.observe(this, Observer {
binding.progressBarLoading.isVisible = false
adapter.setData(it)
})
//button to favorite activity
binding.floatingBtnFavorite.setOnClickListener {
startActivity(Intent(this, FavoriteActivity::class.java))
}
}
Simple RecyclerView Sample using Room, Koin, ViewModel.
RecyclerView, ViewModel, liveData structure is similar to Pokemon List View. However, for Data, Room is used instead of Retrofit in order to save Favorites.
when a pokemon is clicked in ListActivity, clicked pokemon is add to favorite using Room database. In favorite Activity (through floating button), added pokemon can be deleted from favorite.
| RecyclerView without paging | RecyclerView with paging |
|---|---|
 |
 |
Paging3 helps load and display pages of data from a larger dataset from local storage or over network. This will help configure RecyclerView adapters that automatically request data as the user scrolls toward the end of the loaded data.
paging3 needs PagingRepository, PagingSource, and PagingAdapter
Used Hilt instead of Koin for Dependancy Injection
MIT License
Copyright (c) 2021 Daniel Kim
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