ı am trying to use a method which is getValues(). Im trying to take all my value variable from my SQL table and trying to make an addition with them. At the end, ı am trying to print my "value list" but it is just returning "Unit". The result that ı'm trying to reach: sum them all and get the total result.
var incomeList: List<Int> = mIncomeViewModel.getValues() // it is automaticly corrects me as incomeList: Unit
#Dao
interface IncomeDao {
#Insert(onConflict = OnConflictStrategy.IGNORE)
suspend fun addIncome(income: Income)
#Update
suspend fun updateIncome(income: Income)
#Delete
suspend fun deleteIncome(income: Income)
#Query("DELETE FROM income_table")
suspend fun deleteAllIncomes()
#Query("SELECT * FROM income_table ORDER BY id ASC")
fun readAllData(): LiveData<List<Income>>
#Query("SELECT value FROM income_table ")
fun getValues(): LiveData<List<Int>>
}
class IncomeRepository (private val incomeDao: IncomeDao) {
val readAllData: LiveData<List<Income>> = incomeDao.readAllData()
suspend fun addIncome(income: Income){
incomeDao.addIncome(income)
}
suspend fun updateIncome(income: Income){
incomeDao.updateIncome(income)
}
suspend fun deleteIncome(income: Income){
incomeDao.deleteIncome(income)
}
suspend fun deleteAllIncomes(){
incomeDao.deleteAllIncomes()
}
fun getValues(): LiveData<List<Int>> {
return incomeDao.getValues()
}
}
class IncomeViewModel(application: Application): AndroidViewModel(application) {
val readAllData: LiveData<List<Income>> //if anything happens by the private of this variable make it public again
private val repository: IncomeRepository
init {
val incomeDao = IncomeDatabase.getDatabase(application).incomeDao()
repository = IncomeRepository(incomeDao)
readAllData = repository.readAllData
}
fun addIncome(income: Income){
viewModelScope.launch(Dispatchers.IO){
repository.addIncome(income)
}
}
fun updateIncome(income: Income){
viewModelScope.launch(Dispatchers.IO){
repository.updateIncome(income)
}
}
fun deleteIncome(income: Income){
viewModelScope.launch(Dispatchers.IO) {
repository.deleteIncome(income)
}
}
fun deleteAllIncomes(){
viewModelScope.launch(Dispatchers.IO) {
repository.deleteAllIncomes()
}
}
fun getValues(){
viewModelScope.launch(Dispatchers.IO) {
repository.getValues()
}
}
}
Edit:
I fixed my problem with returning the ViewModel methods as LiveData<List>
fun getValues(): LiveData<List<Int>>{
return repository.getValues()
}
Related
I'm newbie in coding, so I want to ask more experienced programmers how to do it right.
I have 2 functions, first from Facebook SDK and second from AppsFlyerLib.
Can you tell me if there is right option to wait results from this functions please.
Here example of code:
class MainActivity: AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) {
super.onCreate(savedInstanceState, persistentState)
var linkdataPlusApps = ""
//Getting Link Data
val linkdataHandler = object : AppLinkData.CompletionHandler {
override fun onDeferredAppLinkDataFetched(appLinkData: AppLinkData?) {
linkdataPlusApps += appLinkData.toString()
}
}
AppLinkData.fetchDeferredAppLinkData(this, linkdataHandler)
//Gettings Apps
val appsdataHandler = object : AppsFlyerConversionListener {
override fun onConversionDataSuccess(p0: MutableMap<String, Any>?) {
linkdataPlusApps += p0.toString()
}
override fun onConversionDataFail(p0: String?) {}
override fun onAppOpenAttribution(p0: MutableMap<String, String>?) {}
override fun onAttributionFailure(p0: String?) {}
}
AppsFlyerLib.getInstance().init("APPS_KEY", appsdataHandler, this).start(this)
//Here I wanna take this data and put in another activity
val intent = Intent(this, NextActivity::class.java)
intent.putExtra("FetchedData", linkdataPlusApps)
startActivity(intent)
}}
But this code doesn't work because Activity started before data was fetched so string is empty.
I solved this by chaining code, but I'm sure that is dirty-coding.
How I did
class MainActivity: AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) {
super.onCreate(savedInstanceState, persistentState)
var linkdataPlusApps = ""
//Getting Link Data
val linkdataHandler = object : AppLinkData.CompletionHandler {
override fun onDeferredAppLinkDataFetched(appLinkData: AppLinkData?) {
linkdataPlusApps += appLinkData.toString()
val appsdataHandler = object : AppsFlyerConversionListener {
override fun onConversionDataSuccess(p0: MutableMap<String, Any>?) {
linkdataPlusApps += p0.toString()
val intent = Intent(this#MainActivity, NextActivity::class.java)
intent.putExtra("FetchedData", linkdataPlusApps)
startActivity(intent)
}
override fun onConversionDataFail(p0: String?) {}
override fun onAppOpenAttribution(p0: MutableMap<String, String>?) {}
override fun onAttributionFailure(p0: String?) {}
}
AppsFlyerLib.getInstance().init("APPS_KEY", appsdataHandler, this#MainActivity).start(this#MainActivity)
}
}
AppLinkData.fetchDeferredAppLinkData(this, linkdataHandler)
}
}
So code starts from fetching AppLinkData, and when fetched, starting fetching apps, and only then starting second activity with right string.
Can I do it in another way?
class SummonerInfoActivity: AppCompatActivity() {
private lateinit var participantAdapter: ParticipantAdapter
private val recycler: RecyclerView by lazy {
findViewById(R.id.RecyclerView)
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val Summoner = intent.getParcelableExtra<SummonerDTO>("SummonerDTO")
Log.e("Info","${Summoner}")
val retrofit2 = Retrofit.Builder()
.baseUrl("https://asia.api.riotgames.com")
.addConverterFactory(GsonConverterFactory.create())
.build()
lolAPIForMatch = retrofit2.create(lolAPIService::class.java)
setContentView(R.layout.activity_summoner_info)
participantAdapter = ParticipantAdapter()
recycler.adapter = participantAdapter
recycler.layoutManager = LinearLayoutManager(this#SummonerInfoActivity)
getMatchIdBypuuid(Summoner?.puuId.orEmpty(),Summoner?.summonerName.orEmpty())
}
private fun getMatchIdBypuuid(puuid: String,summonerName: String){
lolAPIForMatch.getMatchIdBypuuid(puuid, 0,20, API_KEY)
.enqueue(object : Callback<List<String>> {
override fun onResponse(
call: Call<List<String>>,
response: Response<List<String>>
) {
if(response.isSuccessful.not()){
return
}
response.body()?.let {
it.forEach {
searchMatchInfoByMatchID(it,summonerName)
}
}
}
override fun onFailure(call: Call<List<String>>, t: Throwable) {
}
})
}
private fun searchMatchInfoByMatchID(matchId: String,summonerName: String){
lolAPIForMatch.getMatchInfoByMatchID(matchId, API_KEY)
.enqueue(object : Callback<MatchDTO>{
override fun onResponse(call: Call<MatchDTO>, response: Response<MatchDTO>) {
if(response.isSuccessful.not()){
return
}
response.body()?.let {
it.info.participants.filter {
it.summonerName == "${summonerName}"
}.forEach {
participantAdapter.participants.add(it)
}
}
}
override fun onFailure(call: Call<MatchDTO>, t: Throwable) {
}
})
}
}
class ParticipantAdapter: RecyclerView.Adapter<ParticipantAdapter.ViewHolder>() {
var participants = mutableListOf<ParticipantDTO>()
inner class ViewHolder(itemView: View): RecyclerView.ViewHolder(itemView){
fun bind(participant: ParticipantDTO){
itemView.findViewById<TextView>(R.id.kill).text = participant.kills.toString()
itemView.findViewById<TextView>(R.id.death).text = participant.deaths.toString()
itemView.findViewById<TextView>(R.id.assist).text = participant.assists.toString()
}
}
override fun onCreateViewHolder(
parent: ViewGroup,
viewType: Int
): ParticipantAdapter.ViewHolder {
val inflater = LayoutInflater.from(parent.context)
return ViewHolder(inflater.inflate(R.layout.item_match, parent, false))
}
override fun onBindViewHolder(holder: ParticipantAdapter.ViewHolder, position: Int) {
holder.bind(participants[position])
}
override fun getItemCount(): Int {
return participants.size
}
}
participantAdapter.participants.add(it)
The command is searchMatchInfoByMatchID
In the function, you can check that the value is entered correctly, but
If you check in the onCreate function, the value is not assigned.
I want to use the recycler view by properly assigning a value
I tried to solve this problem, but my skills were not enough.
I desperately need the advice of seniors.
I would really appreciate it if you could show me a code sample if possible
I am using Room in my app with two entities. The whole implementation is below.
The Problem is, the given scheme is fixed, which means I do not change anything regarding DB. When I provide a new version of my app to Users over Google Play Console, I get the following issue in Cryshlytics although I did not change anything for DB, just edited UI or another things, which definetly nothing have to do with DB:
Fatal Exception: java.lang.IllegalStateException: Room cannot verify the data integrity. Looks like you've changed schema but forgot to update the version number. You can simply fix this by increasing the version number.
at androidx.room.RoomOpenHelper.checkIdentity(RoomOpenHelper.java:154)
at androidx.room.RoomOpenHelper.onOpen(RoomOpenHelper.java:135)
.......
Now I am not sure if I change the version of DB, it would work. What is wrong here?
BTW the DB is called from a Fragment like this
val mainDb: MainRepository by lazy { MainRepository(requireContext()) }
val stateDb: StateRepository by lazy { StateRepository(requireContext()) }
What's wrong here?
AppDatabase:
#Database(entities = [Main::class, State::class], version = 1, exportSchema = false)
abstract class AppDatabase : RoomDatabase() {
abstract val mainDao: MainDao
abstract val stateDao: StateDao
companion object {
private var INSTANCE: AppDatabase? = null
fun getInstance(context: Context): AppDatabase? =
INSTANCE ?: synchronized(AppDatabase::class) {
INSTANCE = Room.databaseBuilder(
context.applicationContext,
AppDatabase::class.java,
MY_DB
).allowMainThreadQueries()
.build()
return INSTANCE
}
}
}
Dao:
#Dao
interface StateDao {
#Query("SELECT * FROM $STATE")
fun getAll(): List<State>
#Insert(onConflict = OnConflictStrategy.REPLACE)
fun insert(state: State)
#Update
fun update(state: State)
#Query("DELETE FROM $STATE")
fun drop()
}
#Dao
interface MainDao {
#Query("SELECT * FROM $MAIN")
fun getAll(): List<Main>
#Insert(onConflict = OnConflictStrategy.REPLACE)
fun insert(main: Main)
#Update
fun update(main: Main)
#Query("DELETE FROM $MAIN")
fun drop()
}
Main:
#Entity(tableName = MAIN)
data class Main(
#PrimaryKey #ColumnInfo(name = NUMBER) val number: Int,
#ColumnInfo(name = CARD) val car: String? = EMPTY,
#ColumnInfo(name = MODEL) val model: String? = EMPTY
) : Parcelable {
constructor(parcel: Parcel) : this(
parcel.readInt(),
parcel.readString(),
parcel.readString()
)
override fun writeToParcel(parcel: Parcel, flags: Int) {
parcel.writeInt(number)
parcel.writeString(car)
parcel.writeString(model)
}
override fun describeContents(): Int {
return 0
}
companion object CREATOR : Parcelable.Creator<Main> {
override fun createFromParcel(parcel: Parcel): Main {
return Main(parcel)
}
override fun newArray(size: Int): Array<Main?> {
return arrayOfNulls(size)
}
}
}
State:
#Entity(tableName = STATE)
data class State(
#PrimaryKey #ColumnInfo(name = NUMBER) val number: Int,
#ColumnInfo(name = STATE) val state: String? = EMPTY
) : Parcelable {
constructor(parcel: Parcel) : this(
parcel.readInt(),
parcel.readString()
)
override fun writeToParcel(parcel: Parcel, flags: Int) {
parcel.writeInt(number)
parcel.writeString(question)
}
override fun describeContents(): Int {
return 0
}
companion object CREATOR : Parcelable.Creator<State> {
override fun createFromParcel(parcel: Parcel): State {
return State(parcel)
}
override fun newArray(size: Int): Array<State?> {
return arrayOfNulls(size)
}
}
}
Repository:
class MainRepository(context: Context) {
private val mainDao = AppDatabase.getInstance(context)?.mainDao
fun getAll(): List<Main>? {
return mainDao?.getAll()
}
fun insert(main: Main) {
AsyncInsert(mainDao).execute(main)
}
fun update(main: Main) {
mainDao?.update(main)
}
fun drop() {
mainDao?.drop()
}
private class AsyncInsert(private val dao: MainDao?) : AsyncTask<Main, Void, Void>() {
override fun doInBackground(vararg p0: Main?): Void? {
p0[0]?.let { dao?.insert(it) }
return null
}
}
}
class StateRepository(context: Context) {
private val stateDao = AppDatabase.getInstance(context)?.stateDao
fun drop() {
stateDao?.drop()
}
fun getAll(): List<State>? {
return stateDao?.getAll()
}
fun insert(state: State) {
AsyncInsert(stateDao).execute(state)
}
fun update(state: State) {
stateDao?.update(state)
}
private class AsyncInsert(private val dao: StateDao?) : AsyncTask<State, Void, Void>() {
override fun doInBackground(vararg p0: State?): Void? {
p0[0]?.let { dao?.insert(it) }
return null
}
}
}
Now I am not sure if I change the version of DB, it would work. What is wrong here?
Changing the version would probably not work as the schema, as far as Room is concerned, has changed.
There is either a bug or the schema has been changed.
However, changing the version, would, with a Migration that does nothing (so as to not get a "no migration specified" error), then fail but importantly with an expected (what Room expects the schema to be according to the Entities) found (the schema that exists) discrepancy. This, if there is no bug, could then be used to ascertain what has been changed.
I am discovering Kotlin and android app dev. I fail to get data from my room database (because of Cannot access database on the main thread). So I try with lifecyclescope.
The concerned code, in Fragment onViewCreated function, is :
lifecycleScope.launch {
withContext(Dispatchers.Default) {
val accountConfiguration = viewModel.get();
println("{${accountConfiguration}}")
}
}
The called function (in viewModel) is :
fun get() = viewModelScope.launch {
repository.get()
}
There is the "full" code (simplified), Entity & DAO :
#Entity
data class AccountConfiguration(
#PrimaryKey val server_address: String,
#ColumnInfo(name = "user_name") val user_name: String,
// [...]
)
#Dao
interface AccountConfigurationDao {
#Query("SELECT * FROM accountconfiguration LIMIT 1")
fun flow(): Flow<AccountConfiguration?>
#Query("SELECT * FROM accountconfiguration LIMIT 1")
suspend fun get(): AccountConfiguration?
// [...]
}
Repository :
package fr.bux.rollingdashboard
import androidx.annotation.WorkerThread
import kotlinx.coroutines.flow.Flow
class AccountConfigurationRepository(private val accountConfigurationDao: AccountConfigurationDao) {
val accountConfiguration: Flow<AccountConfiguration?> = accountConfigurationDao.flow()
// [...]
#Suppress("RedundantSuspendModifier")
#WorkerThread
suspend fun get() : AccountConfiguration? {
return accountConfigurationDao.get()
}
}
ViewModel & Factory :
class AccountConfigurationViewModel(private val repository: AccountConfigurationRepository) : ViewModel() {
val accountConfiguration: LiveData<AccountConfiguration?> = repository.accountConfiguration.asLiveData()
// [...]
fun get() = viewModelScope.launch {
repository.get()
}
// [...]
}
class AccountConfigurationViewModelFactory(private val repository: AccountConfigurationRepository) : ViewModelProvider.Factory {
override fun <T : ViewModel> create(modelClass: Class<T>): T {
if (modelClass.isAssignableFrom(AccountConfigurationViewModel::class.java)) {
#Suppress("UNCHECKED_CAST")
return AccountConfigurationViewModel(repository) as T
}
throw IllegalArgumentException("Unknown ViewModel class")
}
}
Fragment :
class AccountConfigurationFragment : Fragment() {
private var _binding: AccountConfigurationFragmentBinding? = null
// This property is only valid between onCreateView and
// onDestroyView.
private val binding get() = _binding!!
private val viewModel: AccountConfigurationViewModel by activityViewModels {
AccountConfigurationViewModelFactory(
(activity?.application as RollingDashboardApplication).account_configuration_repository
)
}
lateinit var accountConfiguration: AccountConfiguration
// [...]
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding.buttonGoBackMain.setOnClickListener {
findNavController().navigate(R.id.action_AccountConfigurationFragment_to_DashboardFragment)
}
lifecycleScope.launch {
withContext(Dispatchers.Default) {
val accountConfiguration = viewModel.get();
println("{${accountConfiguration}}")
}
}
binding.buttonSave.setOnClickListener {
save()
}
}
// [...]
}
In your current code,
lifecycleScope.launch {
withContext(Dispatchers.Default) {
val accountConfiguration = viewModel.get();
println("{${accountConfiguration}}")
}
}
viewModel.get() is not a suspend function, so it returns immediately and proceeds to the next line. It actually returns the Job created by viewModelScope.launch().
If you want your coroutine to wait for the result before continuing you should make the get() function suspend and return the AccountConfiguration?
suspend fun get(): AccountConfiguration? {
return repository.get()
}
You need not change dispatchers to Dispatchers.Default because Room itself will switch to a background thread before executing any database operation.
Right now if there is a configuration change while coroutines inside lifecyclerScope are running, everything will get cancelled and restarted.
A better way would have been to put the suspending calls inside the ViewModel and expose a LiveData/Flow to the UI.
The problem is the viewModel function :
fun get() = viewModelScope.launch {
repository.get()
}
This function must be the coroutine instead launch the coroutine itself. Correct code is :
suspend fun get(): AccountConfiguration? {
return repository.get()
}
I want to test a method of my ViewModel that collects a Flow. Inside the collector a LiveData object is mutated, which I want to check in the end. This is roughly how the setup looks:
//Outside viewmodel
val f = flow { emit("Test") }.flowOn(Dispatchers.IO)
//Inside viewmodel
val liveData = MutableLiveData<String>()
fun action() {
viewModelScope.launch { privateAction() }
}
suspend fun privateAction() {
f.collect {
liveData.value = it
}
}
When I now call the action() method in my unit test, the test finishes before the flow is collected. This is how the test might look:
#Test
fun example() = runBlockingTest {
viewModel.action()
assertEquals(viewModel.liveData.value, "Test")
}
I am using the TestCoroutineDispatcher via this Junit5 extension and also the instant executor extension for LiveData:
class TestCoroutineDispatcherExtension : BeforeEachCallback, AfterEachCallback, ParameterResolver {
#SuppressLint("NewApi") // Only used in unit tests
override fun supportsParameter(parameterContext: ParameterContext?, extensionContext: ExtensionContext?): Boolean {
return parameterContext?.parameter?.type === testDispatcher.javaClass
}
override fun resolveParameter(parameterContext: ParameterContext?, extensionContext: ExtensionContext?): Any {
return testDispatcher
}
private val testDispatcher = TestCoroutineDispatcher()
override fun beforeEach(context: ExtensionContext?) {
Dispatchers.setMain(testDispatcher)
}
override fun afterEach(context: ExtensionContext?) {
Dispatchers.resetMain()
testDispatcher.cleanupTestCoroutines()
}
}
class InstantExecutorExtension : BeforeEachCallback, AfterEachCallback {
override fun beforeEach(context: ExtensionContext?) {
ArchTaskExecutor.getInstance()
.setDelegate(object : TaskExecutor() {
override fun executeOnDiskIO(runnable: Runnable) = runnable.run()
override fun postToMainThread(runnable: Runnable) = runnable.run()
override fun isMainThread(): Boolean = true
})
}
override fun afterEach(context: ExtensionContext?) {
ArchTaskExecutor.getInstance().setDelegate(null)
}
}
You can try either,
fun action() = viewModelScope.launch { privateAction() }
suspend fun privateAction() {
f.collect {
liveData.value = it
}
}
#Test
fun example() = runBlockingTest {
viewModel.action().join()
assertEquals(viewModel.liveData.value, "Test")
}
or
fun action() {
viewModelScope.launch { privateAction()
}
suspend fun privateAction() {
f.collect {
liveData.value = it
}
}
#Test
fun example() = runBlockingTest {
viewModel.action()
viewModel.viewModelScope.coroutineContext[Job]!!.join()
assertEquals(viewModel.liveData.value, "Test")
}
You could also try this,
suspend fun <T> LiveData<T>.awaitValue(): T? {
return suspendCoroutine { cont ->
val observer = object : Observer<T> {
override fun onChanged(t: T?) {
removeObserver(this)
cont.resume(t)
}
}
observeForever(observer)
}
}
#Test
fun example() = runBlockingTest {
viewModel.action()
assertEquals(viewModel.liveData.awaitValue(), "Test")
}
So what I ended up doing is just passing the Dispatcher to the viewmodel constructor:
class MyViewModel(..., private val dispatcher = Dispatchers.Main)
and then using it like this:
viewModelScope.launch(dispatcher) {}
So now I can override this when I instantiate the ViewModel in my test with a TestCoroutineDispatcher and then advance the time, use testCoroutineDispatcher.runBlockingTest {}, etc.