Here is the code:
import javafx.event
import javafx.event.EventHandler
import scalafx.application.{Platform, JFXApp}
import scalafx.application.JFXApp.PrimaryStage
import scalafx.event.ActionEvent
import scalafx.scene.Scene
import scalafx.scene.control.{Button, Label}
import scalafx.Includes._
import scalafx.scene.layout.{VBox, HBox}
object Blocking extends JFXApp {
val statusLbl = new Label("Not started...")
val startBtn = new Button("Start") {
onAction = (e: ActionEvent) => startTask
}
val exitBtn = new Button("Exit") {
onAction = (e: ActionEvent) => stage.close()
}
val buttonBox = new HBox(5, startBtn, exitBtn)
val vBox = new VBox(10, statusLbl, buttonBox)
def startTask = {
val backgroundThread = new Thread {
setDaemon(true)
override def run = {
runTask
}
}
backgroundThread.start()
}
def runTask = {
for(i <- 1 to 10) {
try {
val status = "Processing " + i + " of " + 10
Platform.runLater(() => {
statusLbl.text = status
})
println(status)
Thread.sleep(1000)
} catch {
case e: InterruptedException => e.printStackTrace()
}
}
}
stage = new PrimaryStage {
title = "Blocking"
scene = new Scene {
root = vBox
}
}
}
When the "start" button is pressed, the status label should be updated 10 times, but it is not. From the console you can see the background thread is actually updating the status, but these are not reflected in the UI. Why?
The problem is with the invocation of Platform.runLater. To make it work change it to:
Platform.runLater {
statusLbl.text = status
}
runLater[R](op: => R) takes as an argument a code block that returns a value of type R. You were passing a code block defining an anonymous function. runLater was creating a function, not executing it.
Related
Here is, what I'm trying to do:
A Switch is turned on, starting a service in another thread (works fine so far)
When this service is successful, it should then start another function within the main thread
I don't mind whether the function is called directly by the service or the service is returning a "success"-value to the main thread, what then starts the next function from there.
Here is, what the important parts of the code looks like:
Main thread:
class SendNotif : AppCompatActivity() {
val context = this
private lateinit var Switch: Switch
// Start LocationService when the switch is on
Switch.setOnCheckedChangeListener { buttonView, isChecked ->
if (isChecked) {
Toast.makeText(context, "Starting LocationService", Toast.LENGTH_SHORT).show()
Intent(applicationContext, LocationService::class.java).apply {
action = LocationService.ACTION_START
startService(this)
}
} else {
Toast.makeText(context, "Stopping LocationService", Toast.LENGTH_SHORT).show()
Intent(applicationContext, LocationService::class.java).apply {
action = LocationService.ACTION_STOP
startService(this)
}
}
}
}
fun InitiateMessage() {
// This is the function, that is supposed to start after the LocationService
}
}
This is the LocationService. After being successful, the function InitiateMessage() should start.
class LocationService: Service() {
private val serviceScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
private lateinit var locationClient: LocationClient
var lat = 0.0F
var long = 0.0F
override fun onBind(p0: Intent?): IBinder? {
return null
}
override fun onCreate() {
super.onCreate()
locationClient = DefaultLocationClient(
applicationContext,
LocationServices.getFusedLocationProviderClient(applicationContext)
)
}
// Start or stop the service
override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
when(intent?.action) {
ACTION_START -> start()
ACTION_STOP -> stop()
}
return super.onStartCommand(intent, flags, startId)
}
private fun start() {
// Starting notification
val notification = NotificationCompat.Builder(this, "location")
.setContentTitle("Tracking location...")
.setContentText("Location: null")
.setSmallIcon(R.drawable.ic_launcher_background)
// Can't swipe this notification away
.setOngoing(true)
val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
// Starting the location updates
locationClient
// Every 10 seconds
.getLocationUpdates(10000L)
.catch { e -> e.printStackTrace() }
.onEach { location ->
lat = location.latitude.toString().toFloat() // .takeLast(3) // taking only the last 3 digits
long = location.longitude.toString().toFloat() // .takeLast(3)
val updatedNotification = notification.setContentText(
"Location: ($lat, $long)"
)
// notificationManager.notify(1, updatedNotification.build())
// Geofence
MyGeofence(lat, long)
}
.launchIn(serviceScope)
// startForeground(1, notification.build())
}
private fun stop() {
// Stopping the notification
stopForeground(true)
// Stopping the location service
stopSelf()
}
override fun onDestroy() {
super.onDestroy()
serviceScope.cancel()
}
companion object {
const val ACTION_START = "ACTION_START"
const val ACTION_STOP = "ACTION_STOP"
}
fun MyGeofence(lat : Float, long : Float){
val context = this
var db = DataBaseHandler(context)
var data = db.readData()
// Setting the accuracy of the geofence
val acc = 2
val safelat : Double = data.get(0).LocLat.toFloat().round(acc)
val safelong = data.get(0).LocLong.toFloat().round(acc) // .take(acc).take(acc)
val h = Handler(context.mainLooper)
if(safelat == lat.toFloat().round(acc) && safelong == long.toFloat().round(acc)){
h.post(Runnable { Toast.makeText(context, "You have reached your safe refuge! " + lat.toFloat().round(acc) + " " + long.toFloat().round(acc), Toast.LENGTH_LONG).show() })
// ToDo: Right hereafter the function InitiateMessage() should start
}
else{
h.post(Runnable { Toast.makeText(context, "You are still in great danger! " + lat.toFloat().round(acc) + " " + long.toFloat().round(acc), Toast.LENGTH_LONG).show() })
}
}
fun Float.round(decimals: Int): Double {
var multiplier = 1.0
repeat(decimals) { multiplier *= 10 }
return round(this * multiplier) / multiplier
}
}
So far, I tried it with a Looper, which did not work.
java.lang.RuntimeException: Can't create handler inside thread Thread[DefaultDispatcher-worker-1,5,main] that has not called Looper.prepare()
But I guess the far easier way would be a returned value by the service. How do I implement this, and how do I start the next function through this returned value?
I solved my problem with an observe-function and a companion object, that is a MutableLiveData.
The companion object is placed inside the main thread:
companion object {
// var iamsafe: Boolean = false
val iamsafe: MutableLiveData<Boolean> by lazy {
MutableLiveData<Boolean>()
}
}
The observe-function is placed within onCreate:
val safeObserver = Observer<Boolean> { newState ->
Toast.makeText(context, "Initiating message to my mate.", Toast.LENGTH_SHORT).show()
InitiateMessage()
}
iamsafe.observe(this, safeObserver)
The companion is changed in the second thread like this:
SendNotif.iamsafe.postValue (true)
I wrote an unit test to test if a Map is updated every second. In the code I inserted some println statements to see if the function really is called. The test runs indefinitely until I abort the test, showing the println in system.out. So the function works correctly, but my test does not.
Testcode and programcode are below.
#Test
fun test_count_is_updated_using_turbine(){
runTest {
testScheduler.runCurrent()
viewmodelUnderTest.runningTaskMap.test(2.seconds){
val firstCount = awaitItem()
assertThat(firstCount).containsKey(1)
viewmodelUnderTest.startUpdates()
val secondCount = awaitItem()
viewmodelUnderTest.stopUpdates()
cancelAndIgnoreRemainingEvents()
assertThat(firstCount).isEqualTo(0)
assertThat(secondCount).isEqualTo(1)
}
}
}
Program code in viewmodel:( RunningMapState is initialized with a value when the viewmodel is initialized, so it is not an empty map.)
var runningTaskState:Map<Int, RunningTaskView> = mapOf()
private val _runningTaskMap = MutableStateFlow<Map<Int, RunningTaskView>>(mapOf())
val runningTaskMap: StateFlow<Map<Int, RunningTaskView>>
get()=_runningTaskMap
suspend fun updateRunningTasks() {
if (runningTaskState.isNotEmpty()) {
println("Before update:"+runningTaskState)
runningTaskState.forEach {
it.value.duration += 1000L
}
println("After update:"+runningTaskState)
//val tempMap = runningTaskState.toMap()
_runningTaskMap.update{ runningTaskState }
}
else{
println("map empty")
}
}
fun startUpdates(){
val previousJob = timerJob
timerJob = viewModelScope.launch (dispatcher){
previousJob?.cancelAndJoin()
while (isActive) {
delay(1000L)
updateRunningTasks()
}
}
}
fun stopUpdates(){
viewModelScope.launch(dispatcher) {
timerJob?.cancelAndJoin()
}
}
To test the testcode I wrote a sample program replacing the map with a Integer. This test functions as expected and passes. Viewmodelcode and testcode are nearly identical.
See below code:
#Test
fun test_count_is_updated_using_turbine(){
runTest {
testDispatcher.scheduler.runCurrent()
viewmodelUnderTest.countFlow.test(2.seconds){
val firstCount = awaitItem()
val started = viewmodelUnderTest.startTimer()
val secondCount = awaitItem()
viewmodelUnderTest.stoptimer()
cancelAndIgnoreRemainingEvents()
assertThat(started).isTrue()
assertThat(firstCount).isEqualTo(0)
assertThat(secondCount).isEqualTo(1)
}
}
}
Viewmodel:
var count = 0
var countFlow = MutableStateFlow<Int>(0)
fun updateTimer(){
count++
countFlow.update { count }
println("count updated to $count")
}
fun stoptimer(){
viewModelScope.launch {
timerJob?.cancelAndJoin()
}
}
fun startTimer():Boolean{
val previousJob = timerJob
timerJob = viewModelScope.launch(dispatcher) {
previousJob?.cancelAndJoin()
println("start updating")
while(isActive) {
delay(1000L)
println("calling update")
updateTimer()
println("update called")
}
}
println("TimerTest is active: "+timerJob?.isActive?.toString()?:"not initialized")
return timerJob?.isActive?:false
}
Can anyone explain why the first test is not finishing?
I'm trying to pass a constantly updating variable "message" across my Jetpack Composables. I have a draggable box that tracks the coordinates of the box but I'm trying to send the real-time data through a TCP connection. However, I noticed that the current coordinate of the draggable box isn't passing through to the other Composable or the socket -only the same value is passed despite message changing continuously due to me dragging the box. Also, the moment dataSendButton() is pressed, the createDragImage() and its draggable box stops animating/running.
var message = "" // global Android send message
class MainActivity : ComponentActivity() {
private var textView: TextView? = null
dataSendButton()
createDragImage()
...
}
}
}
#Composable
fun createDragImage(){
val context = LocalContext.current
...
Box() {
var offsetX by remember { mutableStateOf(0f) }
var offsetY by remember { mutableStateOf(0f) }
Box(
Modifier
.offset { IntOffset(offsetX.roundToInt(), offsetY.roundToInt()) }
.background(Color.Transparent)
.size(150.dp)
.border(BorderStroke(4.dp, SolidColor(Color.Red)))
.pointerInput(Unit) {
detectDragGestures { change, dragAmount ->
change.consumeAllChanges()
offsetX = someConstantX
offsetY += dragAmount.y
message = offsetY.toString()
...
#Composable
fun dataSendButton() {
val context = LocalContext.current
...
Button(
onClick = {
// **ISSUE: message in this composable is not getting updated with message value from createDragImage()
val b1 = MainActivity.TCPconnector_client(context, message)
b1.execute()
},
{
Text(text = "Send Data", color = Color.White, fontSize = 20.sp)
}
}
}
}
}
It is because that is not how you store state in Compose.
Change the declaration of the variable.
var message by mutableStateOf(...)
Then the changes to it will trigger a recomposition, and so the rest of the code should remain the same. It is always recommended to store the state holders in a viewmodel, and pass the viewmodel around instead.
This is a working code with viewmodel
class MainActivity : ComponentActivity() {
private var textView: TextView? = null
val vm by viewmodels<MViewModel>()
dataSendButton(vm.message, vm:: onMessageChange)
createDragImage(vm.message)
...
}
}
}
#Composable
fun createDragImage(message: String, onMessageChange: (String) -> Unit){
val context = LocalContext.current
...
Box() {
var offsetX by remember { mutableStateOf(0f) }
var offsetY by remember { mutableStateOf(0f) }
Box(
Modifier
.offset { IntOffset(offsetX.roundToInt(), offsetY.roundToInt()) }
.background(Color.Transparent)
.size(150.dp)
.border(BorderStroke(4.dp, SolidColor(Color.Red)))
.pointerInput(Unit) {
detectDragGestures { change, dragAmount ->
change.consumeAllChanges()
offsetX = someConstantX
offsetY += dragAmount.y
onMessageChange (offsetY.toString())
...
#Composable
fun dataSendButton(message: String) {
val context = LocalContext.current
...
Button(
onClick = {
// **ISSUE: message in this composable is not getting updated with message value from createDragImage() // This seems to be an error. Calling a Composable from onClick?
val b1 = MainActivity.TCPconnector_client(context, message)
b1.execute()
},
{
Text(text = "Send Data", color = Color.White, fontSize = 20.sp)
}
}
}
}
}
class MViewModel: ViewModel(){
var message by mutableStateOf("")
private set //do not allow external modifications to ensure consistency
fun onMessageChange (newMessage: String){
message = newMessage
}
}
Note this is the ideal way of doing such implementation. However, for your specific case, if you do not need to access it anywhere else, only changing the declaration as described in the second line of the answer should do
Thanks
In my android project, I use objectbox as database, if I insert with lock and query without lock, is there any side effect ? such as crash and so on.
fun query(uniqueId: String = ""): MutableList<T> {
if (box.store.isClosed) return mutableListOf()
val query = box.query()
withQueryBuilder(query, uniqueId)
//开始
return query.build().find()
}
private fun putInner(entity: T): Long {
synchronized(box.store) {
if (box.store.isClosed) return -1
if (entity.unique.isBlank()) {
entity.unique = entity.providerUnique()
}
entity.timestamp = System.currentTimeMillis()
return try {
box.put(entity).let { id -> entity.id = id }
entity.id
} catch (ex: Exception) {
-1
}
}
}
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.