I am testing the ViewModel which is extended by AndroidViewModel(application).
Below is my ViewModel
#RequiresApi(Build.VERSION_CODES.M)
#HiltViewModel
class HomeFragmentViewModel #Inject constructor(
private val repository: MoviesRepository,
application: Application
) : AndroidViewModel(application) {
var movieData: MutableLiveData<List<Data>> = MutableLiveData()
val isLoading = MutableLiveData(false)
val errorMessage = MutableLiveData<String?>(null)
init {
getData()
}
private fun getData() {
if (checkInternetConnection()) {
viewModelScope.launch {
isLoading.postValue(true)
kotlin.runCatching {
repository.getMoviesData().sortedBy { it.title }
}.onSuccess {
movieData.postValue(it)
isLoading.postValue(false)
}.onFailure {
errorMessage.postValue(it.message)
isLoading.postValue(false)
}
isLoading.postValue(false)
}
} else {
errorMessage.postValue("Internet not available")
}
}
suspend fun filterMovies(searchTerm: String) {
movieData.value = repository.getMoviesData().filter { mvData ->
mvData.genre.contains(searchTerm, ignoreCase = true) ||
mvData.title.contains(searchTerm, ignoreCase = true)
}
}
private fun checkInternetConnection(): Boolean {
val connectivityManager =
getApplication<Application>().getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val activeNetwork = connectivityManager.activeNetwork ?: return false
val capabilities = connectivityManager.getNetworkCapabilities(activeNetwork) ?: return false
return when {
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> true
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> true
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) -> true
else -> false
}
}
}
Now I want this application class to be mocked in the test to initialize the viewmodel to write the test case.
Below is my test which I have written :
class HomeFragmentViewModelTest {
#get:Rule
val rule = InstantTaskExecutorRule()
#ExperimentalCoroutinesApi
#get:Rule
val mainDispatcherRule = MainDispatcherRule()
private val repository: MoviesRepository = mockk{
coEvery { getMoviesData() } returns movieList
}
private val observer: Observer<List<Data>> = mockk(relaxed = true)
private lateinit var viewModel: HomeFragmentViewModel
val context: Context = mock(Context::class.java)
val application: Application = mock(Application::class.java)
private val movieList = listOf(
Data(
id = 0,
year = "1984",
title = "Coming to America",
genre = "Comedy",
poster = ""
),
Data(
id = 1,
year = "2022",
title = "Coming 2 America",
genre = "Comedy",
poster = ""
),
Data(
id = 2,
year = "2020",
title = "Lucky",
genre = "Action",
poster = ""
)
)
#Before
fun setUp() {
viewModel = HomeFragmentViewModel(repository, application = application)
viewModel.movieData.observeForever(observer)
}
#After
fun tearDown() {
viewModel.movieData.removeObserver(observer)
}
#Test
fun `filter movies by genre should return matching genres`() = runBlocking {
val expectedList = listOf(
Data(
id = 0,
year = "1984",
title = "Coming to America",
genre = "Comedy",
poster = ""
),
Data(
id = 1,
year = "2022",
title = "Coming 2 America",
genre = "Comedy",
poster = ""
)
)
viewModel.filterMovies("Comedy")
verify { observer.onChanged(expectedList) }
assertEquals(expectedList, viewModel.movieData.value)
}
}
Now while running the test I am getting below error :
class java.lang.Object cannot be cast to class android.net.ConnectivityManager (java.lang.Object is in module java.base of loader 'bootstrap'; android.net.ConnectivityManager is in unnamed module of loader 'app')
java.lang.ClassCastException: class java.lang.Object cannot be cast to class android.net.ConnectivityManager (java.lang.Object is in module java.base of loader 'bootstrap'; android.net.ConnectivityManager is in unnamed module of loader 'app')
at com.harry.moviesapp.viewModel.HomeFragmentViewModel.checkInternetConnection(HomeFragmentViewModel.kt:62)
at com.harry.moviesapp.viewModel.HomeFragmentViewModel.getData(HomeFragmentViewModel.kt:34)
at com.harry.moviesapp.viewModel.HomeFragmentViewModel.<init>(HomeFragmentViewModel.kt:30)
at com.harry.moviesapp.viewModel.HomeFragmentViewModelTest.setUp(HomeFragmentViewModelTest.kt:77)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
at org.junit.internal.runners.statements.RunBefores.invokeMethod(RunBefores.java:33)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:61)
at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:61)
at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
at org.gradle.api.internal.tasks.testing.worker.TestWorker$2.run(TestWorker.java:176)
at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129)
at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100)
at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60)
at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56)
at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:133)
at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:71)
at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)
at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)
I have checked similar links such as How to mock Application class to unit test ViewModel
But my code is not working. Is there any way to initialize the application class using Mockito?
the first is check the use mockk instead mock for the generate the test doubles.
But the problem per se is that not provides a mock to the ConnectivityManager:
every {
context.getSystemService(Context.CONNECTIVITY_SERVICE)
} returns yourMock
The above is complicated (Everything related to mock of the context is complex)
Maybe your can move the internet validation to another class and generate a static access to the utility, with this also isn't necessary to use AndroidViewModel.
Related
I have this app which displays a list of "coins" to the users . This list was parsed from an JSON API and I used Jetpack Compose for the UI. I implemented
Here is the code of the Jetpack composable list of "coins"
#Composable
fun CoinListScreen(
navController: NavController,
viewModel: CoinListViewModel = hiltViewModel(),
) {
val state = viewModel.state.value
Surface {
Box(modifier = Modifier.fillMaxSize()) {
Column {
androidx.compose.foundation.Image(painter = painterResource(id = R.drawable.ic_baseline_currency_bitcoin_24),
contentDescription = "BTC",
modifier = Modifier
.fillMaxWidth()
.align(CenterHorizontally)
.size(50.dp, 50.dp)
)
SearchBar(
hint = "Search..",
modifier = Modifier
.fillMaxWidth()
.padding(16.dp)
){
viewModel.searchCoinsList(it) **//here I'm calling my search function from the view model, inside my search bar**
}
LazyColumn(modifier = Modifier.fillMaxSize()) {
items(state.coins) { coin ->
Spacer(modifier = Modifier.height(5.dp))
CoinListItem(
coin = coin,
onItemClick = {
navController.navigate(Screen.CoinDetailScreen.route + "/${coin.id}")
}
)
Divider()
}
}
}
if (state.error.isNotBlank()) {
Text(
text = state.error,
color = MaterialTheme.colors.error,
textAlign = TextAlign.Center,
modifier = Modifier
.fillMaxWidth()
.padding(horizontal = 20.dp)
.align(Alignment.Center)
)
}
if (state.isLoading) {
CircularProgressIndicator(modifier = Modifier.align(Alignment.Center))
}
}
}
}
**//and this Is my composable search bar**
#Composable
fun SearchBar(
modifier: Modifier = Modifier,
hint: String = "",
onSearch: (String) -> Unit = {}
) {
var text by remember {
mutableStateOf("")
}
var isHint by remember {
mutableStateOf(hint != "")
}
Box(modifier = modifier){
BasicTextField(
value = text,
onValueChange = {
text = it
onSearch(it)
},
maxLines = 1,
singleLine = true,
modifier = Modifier
.fillMaxWidth()
.shadow(5.dp, CircleShape)
.background(Color.White, CircleShape)
.padding(horizontal = 20.dp, vertical = 12.dp)
.onFocusChanged {
isHint = it.isFocused != true
}
)
if(isHint){
Text(
text = hint,
color = Color.LightGray,
modifier = Modifier.padding(horizontal = 20.dp, vertical = 12.dp)
)
}
}
}
and this is my view model, this is where I'm implementing the search function, this is where I'm lost, variables that I'm searching for are name, rank, and symbol from the Coin domain list
#HiltViewModel //injecting the use case
class CoinListViewModel #Inject constructor (
private val getCoinsUseCase: GetCoinsUseCase,
) : ViewModel() {
//vmstate Live Template, only the view model touches it
private val _state =
mutableStateOf(CoinListState())
val state: State<CoinListState> = _state
**//for search purposes , this is where I'm lost**
private var coinsList = mutableStateOf<List<Coin>>(listOf())
private var cachedCoinsList = listOf<Coin>()
private var isSearchStarting = true
private var isSearching = mutableStateOf(false)
init {
getCoins()
}
**//for search purposes , this is where I'm lost**
fun searchCoinsList(query: String){
val listToSearch = if(isSearchStarting){
coinsList.value
} else {
cachedCoinsList
}
viewModelScope.launch(Dispatchers.Default) {
if(query.isEmpty()){
coinsList.value = cachedCoinsList
isSearching.value = false
isSearchStarting = true
return#launch
}
val results = listToSearch.filter {
//val iterate: Int = coins.size
it.name.contains(query.trim(), ignoreCase = true) ||
(it.rank.toString() == query.trim()) ||
it.symbol.contains(query.trim(), ignoreCase = true)
}
if(isSearchStarting){
cachedCoinsList = coinsList.value
isSearchStarting = false
}
coinsList.value = results
isSearching.value = true
}
}
//function that calls our GetCoinsUseCase and puts the data inside the state object
//to display that in the UI
private fun getCoins() {
//overwrote the invoke function earlier for the use case which allows us to call the use case as a function
getCoinsUseCase().onEach { result ->
when (result) {
is Resource.SUCCESS -> {
_state.value =
CoinListState(coins = result.data ?: arrayListOf())
}
is Resource.ERROR -> {
_state.value =
CoinListState(
error = result.message ?: "An unexpected error occurred"
)
}
is Resource.LOADING -> {
_state.value = CoinListState(isLoading = true)
}
}
}.launchIn(viewModelScope)
}
}
CoinsListState data class used in view model
data class CoinListState(
val isLoading: Boolean = false,
val coins: ArrayList<Coin> = arrayListOf(),
val error: String = ""
)
this is my "GetCoinsUseCase" to get the coins
class GetCoinsUseCase #Inject constructor(
private val repository: CoinRepository
) {
// overwriting the operator fun invoke allows us to call the use case
//GetCoinsUseCase as if it was a function, and we return a flow because
// we want to emit states LOADING -> for progress bar, SUCCESS -> attach list of coins,
// and ERROR
operator fun invoke(): kotlinx.coroutines.flow.Flow<Resource<ArrayList<Coin>>> = flow {
try {
emit(Resource.LOADING<ArrayList<Coin>>())
//we mapped it to toCoin because we returning a list of coin, not coinDTO
val coins = repository.getCoins().map { it.toCoin() }
emit(Resource.SUCCESS<ArrayList<Coin>>(coins as ArrayList<Coin>))
}catch (e: HttpException){
emit(Resource.ERROR<ArrayList<Coin>>(e.localizedMessage ?: "An unexpected error occurred"))
}catch (e: IOException){
emit(Resource.ERROR<ArrayList<Coin>>("Couldn't reach server. Check connection"))
}
}
}
just the coin repository that is implemented in another place
interface CoinRepository {
//repository definitions
suspend fun getCoins() : ArrayList<CoinDTO>
suspend fun getCoinById(coinId: String) : CoinDetailDTO
}
This is my domain - Domain - only contains the data needed
data class Coin(
var id: String,
var isActive: Boolean,
var name: String,
var rank: Int,
var symbol: String
)
and this is how I'm mapping it
data class CoinDTO(
val id: String,
#SerializedName("is_active")
val isActive: Boolean,
#SerializedName("is_new")
val isNew: Boolean,
val name: String,
val rank: Int,
val symbol: String,
val type: String
)
fun CoinDTO.toCoin(): Coin {
return Coin(
id = id,
isActive = isActive,
name = name,
rank = rank,
symbol = symbol,
// logo = CoinDetailLogo(logo = String()).logo
)
}
Coin list item if needed for reference, this is what is displayed to the user in the list
#Composable
fun CoinListItem (
coin: Coin,
onItemClick: (Coin) -> Unit
) {
Row(
modifier = Modifier
.fillMaxWidth()
.clickable { onItemClick(coin) }
.padding(20.dp),
horizontalArrangement = Arrangement.SpaceBetween
) {
Text(
text = "${coin.rank}. ${coin.name} (${coin.symbol})",
style = MaterialTheme.typography.body1,
overflow = TextOverflow.Ellipsis
)
Text(
text = if(coin.isActive) "active" else "inactive",
color = if(coin.isActive) Color.Green else Color.Red,
fontStyle = FontStyle.Italic,
textAlign = TextAlign.End,
style = MaterialTheme.typography.body2,
modifier = Modifier.align(CenterVertically)
)
}
}
as well as the "Resource" generic for states
//UIStates
sealed class Resource<T>(val data: T? = null, val message: String? = null) {
class SUCCESS<T>(data: T) : Resource<T>(data)
class ERROR<T>(message: String, data: T? = null) : Resource<T>(data, message)
class LOADING<T>(data: T? = null) : Resource<T>(data)
}
again, given this info, how can I get the function searchCoinList in the view model to correctly view the searched data (name, rank, or symbol) when it is called in the CoinListScreen inside the Search Bar. Thank you so much
It seems like you want to implement a basic instant search functionality. It's pretty easy to achieve using Kotlin's StateFlow and its operators. Consider the following implementation with description:
// CoinListViewModel
private val queryFlow = MutableStateFlow("")
private val coinsList = mutableStateOf<List<Coin>>(listOf())
init {
queryFlow
.debounce(300) // filters out values that are followed by the newer values within the given timeout. The latest value is always emitted.
.filterNot { query -> userInput.isEmpty() } // filter the unwanted string like an empty string in this case to avoid the unnecessary network call.
.distinctUntilChanged() // to avoid duplicate network calls
.flowOn(Dispatchers.IO) // Changes the context where this flow is executed to Dispatchers.IO
.flatMapLatest { query -> // to avoid the network call results which are not needed more for displaying to the user
getCoinsUseCase(query).catch { emitAll(flowOf(emptyList())}
}
.onEach { coins: List<Coin> -> // go through each list of Coins
coinsList.value = coins
}
.launchIn(viewModelScope)
}
fun searchCoinsList(query: String) {
queryFlow.value = query
}
Main Fragment:
here were initializing the recyclerview and the viewmodel and getting the data to submit to the adapter:
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val binding: FragmentMainBinding = FragmentMainBinding.inflate(inflater, container, false)
this.binding = FragmentMainBinding.inflate(layoutInflater)
dataFromViewModel = arrayListOf()
setupViewModel()
setupList()
setupView()
return binding.root;
}
private fun setupView() {
viewLifecycleOwner.lifecycleScope.launchWhenCreated {
viewModel.listData.collectLatest {
Log.e("Output Frg", it.toString())
if (!dataFromViewModel.contains(it)) {
dataFromViewModel.add(it)
mainAdapter.submitData(it)
mainAdapter.notifyDataSetChanged()
Log.e(TAG, "setupView: ${mainAdapter.repos.toString()}", )
}
}
}
}
private fun setupList() {
mainAdapter = MainAdapter()
val gridLayoutManager: GridLayoutManager = GridLayoutManager(context, 2)
binding.recyclerview.apply {
layoutManager = gridLayoutManager
adapter = mainAdapter
}
// mainAdapter.addLoadStateListener { loadState ->
//
// if (loadState.refresh is LoadState.Loading && !flag) {
// binding.progressbar.visibility = View.VISIBLE
// flag = true
// } else {
// binding.progressbar.visibility = View.GONE
// }
// }
}
private fun setupViewModel() {
viewModel =
ViewModelProvider(
this,
ViewModelFactory(RetrofitService.getApiService())
)[MainViewModel::class.java]
}
Main ViewModel:
here were just calling the postdatasource function and adding it to the listData value
class MainViewModel(private val apiService: RetrofitService) : ViewModel() {
val listData = Pager(PagingConfig(pageSize = 6)) {
PostDataSource(apiService)
}.flow.cachedIn(viewModelScope)
}
PostDataSource:
Here, we have extended PostDataSource with PagingSource which will implement a suspend load function which will help us to load the data.
PostDataSource also takes a primary constructor parameter APIService. PostDataSource acts here as a repository and the load function gets the data from the API.
Since the load function is a suspend function, we can call other suspend functions inside it without any issues which we created in APIService.
In the PostDataSource, we take two parameters one of integer type and other of the data type we have to load on the list item. The integer parameter represents the page number here.
Here, we get the page number from params and assign it to nextPage variable using param.key and if it returns null, we set a default value 1.
We also do the API call and get assign the response to the response variable using APIService which we passed as a constructor parameter to PostDataSource class.
After doing all the operations with the successful response, we return the LoadResult.Page object here with the required data and it something went wrong we use LoadResult.Error.
We are also passing null as the next key if there is no corresponding data in that direction.
class PostDataSource(private val apiService: RetrofitService) : PagingSource<Int, repo>() {
override suspend fun load(params: LoadParams<Int>): LoadResult<Int, repo> {
try {
val currentLoadingPageKey = params.key ?: 1
val response = apiService.getListData(currentLoadingPageKey)
val responseData = mutableListOf<repo>()
var repos : List<repo>
val data = response
responseData.addAll(data)
Log.e(TAG, "load: $responseData", )
val prevKey = if (currentLoadingPageKey == 1) null else currentLoadingPageKey - 1
return LoadResult.Page(
data = responseData,
prevKey = prevKey,
nextKey = currentLoadingPageKey.plus(1)
)
} catch (e: Exception) {
return LoadResult.Error(e)
}
}
override fun getRefreshKey(state: PagingState<Int, repo>): Int? {
return state.anchorPosition?.let { anchorPosition ->
val anchorPage = state.closestPageToPosition(anchorPosition)
anchorPage?.prevKey?.plus(1) ?: anchorPage?.nextKey?.minus(1)
}
}
// fun getAllrepos() = retrofitService.getAllrepos()
}
MainAdapter:
Now, we will update the MainListAdapter. We will extend the MainListAdapter with PagingDataAdapter and the PagingDataAdapter will take the type of data we need to display in the list and the ViewHolder.
It also takes a DiffUtil callback, as a parameter to its primary constructor which helps the PagingDataAdapter to update the items if they are changed or updated. And DiffUtil callback is used because they are more performant.
Now, the MainListAdapter looks like,
class MainAdapter : PagingDataAdapter<repo, MainAdapter.ViewHolder>(DiffCallBack) , Filterable {
private lateinit var Repos : List<repo>
class ViewHolder(view: View, mlistener: onItemClickListener) : RecyclerView.ViewHolder(view)
private lateinit var mlistener: onItemClickListener
interface onItemClickListener {
fun OnItemClick(position: Int)
}
var repos: MutableList<repo> = ArrayList()
private var reposFull: MutableList<repo> = ArrayList()
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.itemView.findViewById<TextView>(R.id.title).text = getItem(position)?.name
Log.e(TAG,"name ${holder.itemView.findViewById<TextView>(R.id.title).text}", )
Glide.with(holder.itemView.context)
.load(getItem(position)?.owner?.avatar_url)
.into(holder.itemView.findViewById(R.id.imgCircle))
// val repo = repos[position]
//
//
// val mainViewHolder: ViewHolder = holder as ViewHolder
// mainViewHolder.itemView Title?.text = repo.name
// mainViewHolder.Image?.let {
// Glide.with(holder.itemView.context).load(repo.owner.avatar_url).into(
// it
// )
// }
}
fun submitList(list: PagingData<repo>) {
Repos = list as List<repo>
notifyDataSetChanged()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return ViewHolder(
LayoutInflater
.from(parent.context)
.inflate(R.layout.repo_layout, parent, false), mlistener
)
}
fun setOnItemClickListener(listener: onItemClickListener) {
mlistener = listener
}
object DiffCallBack : DiffUtil.ItemCallback<repo>() {
override fun areItemsTheSame(oldItem: repo, newItem: repo): Boolean {
return oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: repo, newItem: repo): Boolean {
return oldItem == newItem
}
}
// class MainViewHolder(itemView: View, listener: onItemClickListener) : RecyclerView.ViewHolder(itemView) {
// var Title: TextView? =
// itemView.findViewById<View>(com.lau.google_rep.R.id.title) as TextView
// var Image: ImageView? =
// itemView.findViewById<View>(com.lau.google_rep.R.id.imgCircle) as ImageView
//
// init {
// itemView.setOnClickListener {
// listener.OnItemClick(adapterPosition)
// }
// }
// }
override fun getFilter(): Filter {
return exampleFilter
}
private val exampleFilter: Filter = object : Filter() {
override fun performFiltering(constraint: CharSequence?): FilterResults? {
val filteredList: MutableList<repo> = ArrayList()
if (constraint == null || constraint.length == 0) {
filteredList.addAll(reposFull)
} else {
val filterPattern = constraint.toString().toLowerCase().trim { it <= ' ' }
for (item in reposFull) {
if (item.name.toLowerCase().contains(filterPattern)) {
filteredList.add(item)
}
}
}
Log.d(TAG, "publishResults: $filteredList")
val results = FilterResults()
results.values = filteredList
return results
}
#SuppressLint("NotifyDataSetChanged")
override fun publishResults(constraint: CharSequence?, results: FilterResults) {
repos.clear()
(results.values as? Collection<repo>)?.let { repos.addAll(it) }
notifyDataSetChanged()
}
}
}
retrofit service:
interface RetrofitService {
// #Headers("Authorization: token ")
#GET("repos")
suspend fun getListData(#Query("page") pageNumber: Int): List<repo>
companion object{
private val moshi = Moshi.Builder()
.add(KotlinJsonAdapterFactory())
.build()
fun getApiService() = Retrofit.Builder()
.baseUrl("https://api.github.com/orgs/google/")
.addConverterFactory(MoshiConverterFactory.create(moshi))
.build()
.create(RetrofitService::class.java)
}
}
I have been trying to code a step tracker app. When I build the app, it doesn't show any errors but when I run it, it crashes and throws this:
java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Float
at com.example.fitnesstracker.MainActivity.loadData(MainActivity.kt:159)
at com.example.fitnesstracker.MainActivity.onCreate(MainActivity.kt:48)
I have implemented everything that I need but it won't start.
Here is the code for the saveData() and loadData() where I have the error:
private fun saveData() {
val sharedPreferences = getSharedPreferences("myPrefs", Context.MODE_PRIVATE)
val editor = sharedPreferences.edit()
editor.putFloat("key1", previoustotalSteps)
editor.apply()
}
private fun loadData(){
val sharedPreferences= getSharedPreferences("myPrefs", Context.MODE_PRIVATE)
val savedNumber = sharedPreferences.getFloat("key1", 0f)
Log.d("MainActivity", "$savedNumber")
previoustotalSteps = savedNumber
}
These lines are after the setContentView in the onCreate method:
loadData()
resetSteps()
sensorManager = getSystemService(Context.SENSOR_SERVICE) as SensorManager
And these are the other functions that I use:
override fun onSensorChanged(event: SensorEvent?) {
if(running){
val stepstaken = findViewById<TextView>(R.id.steps_taken_id)
val progressBar = findViewById<CircularProgressBar>(R.id.circularProgressBar)
totalSteps = event!!.values[0]
val currentSteps = totalSteps.toInt() - previoustotalSteps.toInt()
stepstaken.text = currentSteps.toString()
progressBar.apply {
setProgressWithAnimation(currentSteps.toFloat())
}
}
}
private fun resetSteps(){
val stepstaken = findViewById<TextView>(R.id.steps_taken_id)
stepstaken.setOnClickListener {
Toast.makeText(this, "Long tap for step reset.", Toast.LENGTH_SHORT).show()
}
stepstaken.setOnLongClickListener {
previoustotalSteps = totalSteps
stepstaken.text = 0.toString()
saveData()
true
}
}
Also the step counter doesn't work. It stays at 0 no matter how much I move my phone.
I'm trying to store an instance of my Kotlin class into a JSON file using the Gson library. However, when I run Gson().fromJson, I'm receiving the following error:
java.lang.RuntimeException: Failed to invoke public com.keikakupet.PetStatus() with no args
My understanding of the error is that Gson requires that my class has a primary constructor which takes no arguments so it can construct the desired object (in this case, a PetStatus object). However, I have such a constructor. I'm not sure if part of the problem lies in the fact that I'm running the method from the init. Does anyone know how I might fix this error?
My code:
package com.keikakupet
import android.content.Context
import android.util.Log
import com.google.gson.Gson
import java.io.File
import java.util.*
import java.io.BufferedReader
class PetStatus constructor(){
var maxHealth: Int = 10
var currentHealth: Int = 10
var healthIncrementer: Int = 2 // amount by which health increments when a task is completed
var healthDecrementer: Int = 0 // amount by which health decrements when user approaches / misses deadline
var isHungry: Boolean = false
var isTired: Boolean = false
var isSick: Boolean = false
var isAlive: Boolean = true
init{
//if a json exists, use it to update PetStatus
val context = getContext()
var file = File(context.getFilesDir(), "PetStatus.json")
if(file.exists()){
Log.d("FILE_EXISTS", "File exists!")
val bufferedReader: BufferedReader = file.bufferedReader()
val json = bufferedReader.readText()
val retrievedStatus = Gson().fromJson(json, PetStatus::class.java)
Log.d("JSON_RETRIEVED", json)
}
else
Log.d("FILE_DNE", "File does not exist!")
updateJson()
}
// method to update pet's health and ailment upon completing a task
fun processCompletedTask(){
incrementHealth()
removeAilment()
Log.d("TASK_COMPLETE", "completed task processed")
}
fun getHealthPercent(): Int {
return currentHealth / maxHealth
}
// method to update pet's health and ailment upon missing a task
fun processMissedTask(){
decrementHealth()
addAilment()
Log.d("TASK_MISSED", "missed task processed")
}
/*
Potentially creating another method to update pet's
health and status because of an approaching deadline.
*/
// method to decrement the pet's health
private fun decrementHealth(){
currentHealth-=healthDecrementer
if(currentHealth <= 0)
isAlive = false
updateJson()
}
// method to increment the pet's health
private fun incrementHealth(){
val sum = currentHealth + healthIncrementer
if(sum > maxHealth)
currentHealth = maxHealth
else
currentHealth = sum
updateJson()
}
// method to add an ailment to the pet
private fun addAilment(){
// if no ailment, randomly assign hungry or tired
if(!isHungry && !isTired && !isSick){
val rand = Random()
val randBool = rand.nextBoolean()
if(randBool)
isHungry = true
else
isTired = true
healthDecrementer = 1
}
// otherwise, if hungry XOR tired, assign the other
else if(isHungry && !isTired){
isTired = true
healthDecrementer = 2
}
else if(isTired && !isHungry){
isHungry = true
healthDecrementer = 2
}
// otherwise, if both hungry AND tired, assign sick
else if(isHungry && isTired){
isSick = true
healthDecrementer = 3
}
updateJson()
}
// method to remove an ailment from the pet
private fun removeAilment(){
// if sick, remove sick
if(isSick){
isSick = false
healthDecrementer = 2
}
// otherwise, if hungry and tired, remove one of the two randomly
else if(isHungry && isTired){
val rand = Random()
val randBool = rand.nextBoolean()
if(randBool)
isHungry = false
else
isTired = false
healthDecrementer = 1
}
// otherwise, if hungry XOR tired, remove relevant ailment
else if(isHungry && !isTired){
isHungry = false
healthDecrementer = 0
}
else if(isTired){
isTired = false
healthDecrementer = 0
}
updateJson()
}
private fun updateJson(){
val gson = Gson()
var json: String = gson.toJson(this)
Log.d("JSON_UPDATE", json)
val context = getContext()
var file = File(context.getFilesDir(), "PetStatus.json")
file.writeText(json)
val bufferedReader: BufferedReader = file.bufferedReader()
json = bufferedReader.readText()
Log.d("JSON_FROM_FILE", json)
}
companion object {
private lateinit var context: Context
fun setContext(con: Context) {
context=con
}
fun getContext() : Context {
return context
}
}
}
Logcat information:
Caused by: java.lang.RuntimeException: Failed to invoke public com.keikakupet.PetStatus() with no args
at com.google.gson.internal.ConstructorConstructor$3.construct(ConstructorConstructor.java:118)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:212)
at com.google.gson.Gson.fromJson(Gson.java:927)
at com.google.gson.Gson.fromJson(Gson.java:892)
at com.google.gson.Gson.fromJson(Gson.java:841)
at com.google.gson.Gson.fromJson(Gson.java:813)
at com.keikakupet.PetStatus.<init>(PetStatus.kt:32)
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
at com.google.gson.internal.ConstructorConstructor$3.construct(ConstructorConstructor.java:110)
... 4981 more
Since your constructor has no parameters, Gson is not able to instantiate your class with the help of json.
Restructure your class like this:
class PetStatus private constructor(
var maxHealth: Int = 10,
var currentHealth: Int = 10,
var healthIncrementer: Int = 2, // amount by which health increments when a task is completed
var healthDecrementer: Int = 0, // amount by which health decrements when user approaches / misses deadline
var isHungry: Boolean = false,
var isTired: Boolean = false,
var isSick: Boolean = false,
var isAlive: Boolean = true) {
/**
* This is optional fix, since it is a design guideline
* recommendation, you can retain your original function as well
* fun getHealthPercent(): Int {
* return currentHealth / maxHealth
* }
*/
val healthPercent: Int
get() = currentHealth / maxHealth
...
companion object {
lateinit var context: Context // getters and setters for java are automatically generated
operator fun invoke(): PetStatus {
//if a json exists, use it to update PetStatus
val context = context
var file = File(context.getFilesDir(), "PetStatus.json")
if(file.exists()){
Log.d("FILE_EXISTS", "File exists!")
val bufferedReader: BufferedReader = file.bufferedReader()
val json = bufferedReader.readText()
val retrievedStatus = Gson().fromJson(json, PetStatus::class.java)
Log.d("JSON_RETRIEVED", json)
return retrievedStatus
} else {
Log.d("FILE_DNE", "File does not exist!")
return PetStatus()
}
updateJson()
}
operator fun invoke(maxHealth: Int, currentHealth: Int, healthIncrementer: Int, healthDecrementer: Int, isHungry: Boolean, isTired: Boolean, isSick: Boolean, isAlive: Boolean): PetStatus
= PetStatus(maxHealth, currentHealth, healthIncrementer, healthDecrementer, isHungry, isTired, isSick, isAlive)
}
}
Now you can call the class the same
PetStatus()
operator fun invoke() is a hack (ish) approach, I'll recommend you should actually take the code out and instantiate the class from outside.
I have a remote server from where I want to fetch 20 items(Job) per api call and show them in RecyclerView using paging library.
For that, I want to show a loading indicator at the beginning of the first api call when list of items is being fetched from the server. Everything is okay if data is fetched successfully. That means the loading indicator got invisible if data loaded successfully. The code is given bellow.
JobService.KT
#GET(Constants.API_JOB_LIST)
fun getJobPost(
#Query("page") pageNumber: Int
): Observable<Response<JobResponse>>
JobResponse.kt
data class JobResponse(
#SerializedName("status") val status: Int? = null,
#SerializedName("message") val message: Any? = null,
#SerializedName("data") val jobData: JobData? = null
)
JobData.kt
data class JobData(
#SerializedName("jobs") val jobs: List<Job?>? = null,
#SerializedName("total") val totalJob: Int? = null,
#SerializedName("page") val currentPage: Int? = null,
#SerializedName("showing") val currentlyShowing: Int? = null,
#SerializedName("has_more") val hasMore: Boolean? = null
)
NetworkState.kt
sealed class NetworkState {
data class Progress(val isLoading: Boolean) : NetworkState()
data class Failure(val errorMessage: String?) : NetworkState()
companion object {
fun loading(isLoading: Boolean): NetworkState = Progress(isLoading)
fun failure(errorMessage: String?): NetworkState = Failure(errorMessage)
}
}
Event.kt
open class Event<out T>(private val content: T) {
private var hasBeenHandled = false
fun getContentIfNotHandled() = if (hasBeenHandled) {
null
} else {
hasBeenHandled = true
content
}
fun peekContent() = content
}
JobDataSource.kt
class JobDataSource(
private val jobService: JobService,
private val compositeDisposable: CompositeDisposable
) : PageKeyedDataSource<Int, Job>() {
val paginationState: MutableLiveData<Event<NetworkState>> = MutableLiveData()
val initialLoadingState: MutableLiveData<Event<NetworkState>> = MutableLiveData()
val totalJob: MutableLiveData<Event<Int>> = MutableLiveData()
companion object {
private const val FIRST_PAGE = 1
}
override fun loadInitial(params: LoadInitialParams<Int>, callback: LoadInitialCallback<Int, Job>) {
compositeDisposable += jobService.getJobPost(FIRST_PAGE)
.performOnBackgroundOutputOnMain()
.doOnSubscribe { initialLoadingState.postValue(Event(loading(true))) }
.doOnTerminate { initialLoadingState.postValue(Event(loading(false))) }
.subscribe({
if (it.isSuccessful) {
val jobData = it.body()?.jobData
totalJob.postValue(Event(jobData?.totalJob!!))
jobData.jobs?.let { jobs -> callback.onResult(jobs, null, FIRST_PAGE+1) }
} else {
val error = Gson().fromJson(it.errorBody()?.charStream(), ApiError::class.java)
when (it.code()) {
CUSTOM_STATUS_CODE -> initialLoadingState.postValue(Event(failure(error.message!!)))
else -> initialLoadingState.postValue(Event(failure("Something went wrong")))
}
}
}, {
if (it is IOException) {
initialLoadingState.postValue(Event(failure("Check Internet Connectivity")))
} else {
initialLoadingState.postValue(Event(failure("Json Parsing error")))
}
})
}
override fun loadAfter(params: LoadParams<Int>, callback: LoadCallback<Int, Job>) {
compositeDisposable += jobService.getJobPost(params.key)
.performOnBackgroundOutputOnMain()
.doOnSubscribe { if (params.key != 2) paginationState.postValue(Event(loading(true))) }
.doOnTerminate { paginationState.postValue(Event(loading(false))) }
.subscribe({
if (it.isSuccessful) {
val jobData = it.body()?.jobData
totalJob.postValue(Event(jobData?.totalJob!!))
jobData.jobs?.let { jobs -> callback.onResult(jobs, if (jobData.hasMore!!) params.key+1 else null) }
} else {
val error = Gson().fromJson(it.errorBody()?.charStream(), ApiError::class.java)
when (it.code()) {
CUSTOM_STATUS_CODE -> initialLoadingState.postValue(Event(failure(error.message!!)))
else -> initialLoadingState.postValue(Event(failure("Something went wrong")))
}
}
}, {
if (it is IOException) {
paginationState.postValue(Event(failure("Check Internet Connectivity")))
} else {
paginationState.postValue(Event(failure("Json Parsing error")))
}
})
}
override fun loadBefore(params: LoadParams<Int>, callback: LoadCallback<Int, Job>) {}
}
JobDataSourceFactory.kt
class JobDataSourceFactory(
private val jobService: JobService,
private val compositeDisposable: CompositeDisposable
): DataSource.Factory<Int, Job>() {
val jobDataSourceLiveData = MutableLiveData<JobDataSource>()
override fun create(): DataSource<Int, Job> {
val jobDataSource = JobDataSource(jobService, compositeDisposable)
jobDataSourceLiveData.postValue(jobDataSource)
return jobDataSource
}
}
JobBoardViewModel.kt
class JobBoardViewModel(
private val jobService: JobService
) : BaseViewModel() {
companion object {
private const val PAGE_SIZE = 20
private const val PREFETCH_DISTANCE = 20
}
private val jobDataSourceFactory: JobDataSourceFactory = JobDataSourceFactory(jobService, compositeDisposable)
var jobList: LiveData<PagedList<Job>>
init {
val config = PagedList.Config.Builder()
.setPageSize(PAGE_SIZE)
.setInitialLoadSizeHint(PAGE_SIZE)
.setPrefetchDistance(PREFETCH_DISTANCE)
.setEnablePlaceholders(false)
.build()
jobList = LivePagedListBuilder(jobDataSourceFactory, config).build()
}
fun getPaginationState(): LiveData<Event<NetworkState>> = Transformations.switchMap<JobDataSource, Event<NetworkState>>(
jobDataSourceFactory.jobDataSourceLiveData,
JobDataSource::paginationState
)
fun getInitialLoadingState(): LiveData<Event<NetworkState>> = Transformations.switchMap<JobDataSource, Event<NetworkState>>(
jobDataSourceFactory.jobDataSourceLiveData,
JobDataSource::initialLoadingState
)
fun getTotalJob(): LiveData<Event<Int>> = Transformations.switchMap<JobDataSource, Event<Int>>(
jobDataSourceFactory.jobDataSourceLiveData,
JobDataSource::totalJob
)
}
JobBoardFragment.kt
class JobBoardFragment : BaseFragment() {
private val viewModel: JobBoardViewModel by lazy {
getViewModel { JobBoardViewModel(ApiFactory.jobListApi) }
}
private val jobAdapter by lazy {
JobAdapter {
val bundle = Bundle()
bundle.putInt(CLICKED_JOB_ID, it.jobId!!)
navigateTo(R.id.jobBoard_to_jobView, R.id.home_navigation_fragment, bundle)
}
}
override fun getLayoutResId() = R.layout.fragment_job_board
override fun initWidget() {
job_list_recycler_view.adapter = jobAdapter
back_to_main_image_view.setOnClickListener { onBackPressed() }
}
override fun observeLiveData() {
with(viewModel) {
jobList.observe(this#JobBoardFragment, Observer {
jobAdapter.submitList(it)
})
getInitialLoadingState().observe(this#JobBoardFragment, Observer {
it.getContentIfNotHandled()?.let { state ->
when (state) {
is Progress -> {
if (state == loading(true)) {
network_loading_indicator.visible()
} else {
network_loading_indicator.visibilityGone()
}
}
is Failure -> context?.showToast(state.errorMessage.toString())
}
}
})
getPaginationState().observe(this#JobBoardFragment, Observer {
it.getContentIfNotHandled()?.let { state ->
when (state) {
is Progress -> {
if (state == loading(true)) {
pagination_loading_indicator.visible()
} else {
pagination_loading_indicator.visibilityGone()
}
}
is Failure -> context?.showToast(state.errorMessage.toString())
}
}
})
getTotalJob().observe(this#JobBoardFragment, Observer {
it.getContentIfNotHandled()?.let { state ->
job_board_text_view.visible()
with(profile_completed_image_view) {
visible()
text = state.toString()
}
}
})
}
}
}
But the problem is if data fetching failed due to internet connectivity or any other server related problem loading indicator does not invisible that means it still loading though I make the loadingStatus false and error message is shown. it means .doOnTerminate { initialLoadingState.postValue(Event(loading(false))) } is not called if error occured. This is the first problem. Another problem is loadInitial() and loadAfter() is being called simultaneously at the first call. But I just want the loadInitial() method is called at the beginning. after scrolling loadAfter() method will be called.
Try replacing all your LiveData's postValue() methods by setValue() or simply .value =.
The problem is that the postValue() method is for updating the value from a background thread to observers in the main thread. In this case you are always changing the values from the main thread itself, so you should use .value =.
Hope it's not too late.