I want to set a simple switch that'll save a boolean value and if then block in my function.
Currently I have this in my DataStore:
companion object {
private val Context.dataStore: DataStore<Preferences> by preferencesDataStore("userToken")
private val AutoRestartSystemUI = booleanPreferencesKey("AutoRestartSystemUIValue")
}
var getAutoRestartSystemUIValue: Flow<Boolean> = context.dataStore.data.map { preferences ->
(preferences[AutoRestartSystemUI] ?: "") as Boolean
}
suspend fun setAutoRestartSystemUI(value: Boolean) {
context.dataStore.edit { preferences ->
preferences[AutoRestartSystemUI] = value
}
}
}
and
Button(onClick = {
// if [pro.themed.manager.UserStore(context).getAutoRestartSystemUIValue = true] ()
CoroutineScope(Dispatchers.IO).launch {
UserStore(context).setAutoRestartSystemUI(false)
}
}) {
Text(text = UserStore(context).getAutoRestartSystemUIValue.collectAsState(
initial = ""
).toString())
}
in my activity. I have generally no idea of what I should do next and for some weird reason instead of showing value in a text (temp solution for testing) i have
How do i simplify datastore? How do I properly implement switch that'll make it = !it? How to set default value?
Related
Currently Paging library handles when to load the data automatically when a user scrolls down. But what if you want to give the user full authority for when they want the next page of data to be loaded i.e when button is clicked show next page of movies. How can you handle this in Paging library? See below how I've implemented the paging to load data as a user scrolls down
Here below this how I implemented the Paging to load next page when user scrolls down
class MoviesPagingDataSource(
private val repo: MoviesRepository,
) : PagingSource<Int, Movies>() {
override fun getRefreshKey(state: PagingState<Int, Movies>): Int? {
return state.anchorPosition?.let { anchorPosition ->
val anchorPage = state.closestPageToPosition(anchorPosition)
anchorPage?.prevKey?.plus(1) ?: anchorPage?.nextKey?.minus(1)
}
}
override suspend fun load(params: LoadParams<Int>): LoadResult<Int, Movies> {
return try {
val nextPageNumber = params.key ?: 0
val response = repo.getMovies(page = nextPageNumber, size = 10)
LoadResult.Page(
data = response.content,
prevKey = null,
nextKey = if (response.content.isNotEmpty()) response.number + 1 else null
)
} catch (e: Exception) {
LoadResult.Error(e)
}
}
}
This is how I emit the state in ViewModel for the UI to observe
#HiltViewModel
class MoviesViewModel #Inject constructor(
private val moviesRepository: MoviesRepository
): ViewModel {
....
//emitting the data to the UI to observe
val moviesPagingDataSource = Pager(PagingConfig(pageSize = 10)) {
MoviesPagingDataSource(moviesRepository)
}.flow.cachedIn(viewModelScope)
}
How I'm observing it in the UI
#Composable
fun MoviesList(viewModel: MoviesViewModel) {
val moviesList = viewModel.moviesPagingDataSource.collectAsLazyPagingItems()
LazyColumn {
items(moviesList) { item ->
item?.let { MoviesCard(movie = it) }
}
when (moviesList.loadState.append) {
is LoadState.NotLoading -> Unit
LoadState.Loading -> {
item {
LoadingItem()
}
}
is LoadState.Error -> {
item {
ErrorItem(message = "Some error occurred")
}
}
}
when (moviesList.loadState.refresh) {
is LoadState.NotLoading -> Unit
LoadState.Loading -> {
item {
Box(
modifier = Modifier.fillMaxSize(),
contentAlignment = Center
) {
CircularProgressIndicator()
}
}
}
is LoadState.Error -> TODO()
}
}
}
So currently I'm adding 1 to the previous page every time a user clicks the button to load more movies then saving this movies to the list state. Also making sure the current page is greater than or equal to total pages before loading more data and adding to the list state of previous loaded movies
you can use Channel to block LoadResult returning from load, when user clicks the button, send an element to the Channel. here is the simple
class MoviesPagingDataSource(
private val repo: MoviesRepository
) : PagingSource<Int, Movies>() {
private val channel: Channel<Unit> = Channel(1, BufferOverflow.DROP_LATEST)
override fun getRefreshKey(state: PagingState<Int, Movies>): Int? {
return state.anchorPosition?.let { anchorPosition ->
val anchorPage = state.closestPageToPosition(anchorPosition)
anchorPage?.prevKey?.plus(1) ?: anchorPage?.nextKey?.minus(1)
}
}
override suspend fun load(params: LoadParams<Int>): LoadResult<Int, Movies> {
return try {
val nextPageNumber = params.key ?: 0
// load initial page
if (nextPageNumber == 0) loadNextPage()
val response = repo.getMovies(page = nextPageNumber, size = 10)
/*
* block next page data return, when user click the button,
* call loadNextPage. if you don't want to automatically
* request data as the user scrolls toward the end of the
* loaded data. put this line above the repo.getMovies.
**/
channel.receive()
LoadResult.Page(
data = response.content,
prevKey = null,
nextKey = if (response.content.isNotEmpty()) response.number + 1 else null
)
} catch (e: Exception) {
LoadResult.Error(e)
}
}
suspend fun loadNextPage() {
channel.send(Unit)
}
}
I want to be able to manipulate the paste behaviour of an TextField, something along the lines of -
override fun onPaste(pastedText: String){
}
Like how an EditText has
#Override
public boolean onContextItemSelected(MenuItem item) {
AdapterContextMenuInfo info = (AdapterContextMenuInfo)item.getMenuInfo();
switch (item.getItemId()) {
case R.id.paste:
break;
}
return true;
}
I thought of a workaround. When the paste happens, your value usually typically changes by more than 1 symbol, so maybe something like this will work. I know it is hacky, and I would rather write this as a comment, but comment limits will not let me describe it completely.
TextField(
value = textValue,
onValueChange = { newValue ->
textValue = if (newValue.text.length > 1) {
doSomething()
newValue
} else {
newValue
}
}
)
UPD:
Oh I forgot that you can set up a modifier!
TextField(
value = textValue,
onValueChange = {...},
modifier = Modifier
.onKeyEvent { event: KeyEvent ->
if (
event.type == KeyEventType.KeyDown
&& event.key == Key.Paste
) {
// DO SOMETHING
return#onKeyEvent true
}
false
}
)
I'm use DataStore with flow but I cant get any update on the flow when editing DataStore.
Store.kt
private class IStore(private val context: Context): Store {
val eventIDKey = stringPreferencesKey("EventID")
override suspend fun setEventID(eventID: String) {
context.dataStoreSettings.edit { settings ->
settings[eventIDKey] = eventID
}
}
override fun getEventID(): Flow<String> {
return context.dataStoreSettings.data.map { settings -> settings[eventIDKey].orEmpty() }
}
}
and manipulate getEventID() with data from room database in event service
EventService.kt
fun getSelectedEventLive() = store.getEventID()
.onEach { Log.d("EventService", "income new event id $it") }
.flatMapConcat { if(it.isNotBlank()) eventDao.get(it) else flowOf(null) }
onEach called when I collect the data but when updated it's not called again and need to close and open the app to show the latest data
MainViewModel.kt
val selectedEvent = eventService.getSelectedEventLive()
.stateIn(viewModelScope, SharingStarted.Lazily, null)
and use on Compose with this
val currentEvent by mainViewModel.selectedEvent.collectAsState()
Maybe I doing wrong or maybe there is something I miss?
Usually, you want to use flow.collect {...}, since Flow is cold and need to know that it is being collected to start producing new values.
// MainViewModel.kt
private val _selectedEvent = MutableStateFlow<TypeOfYourEvent>()
val selectedEvent: StateFlow<TypeOfYourEvent> = _selectedEvent
init {
viewModelScope.launch {
getSelectedEventLive().collect { it ->
_selectedEvent.value = it
}
}
}
This example should be fine with your composable's code, you still can collect selectedEvent as state.
Yeah i found the solusion its works if i change the flatMapConcat with flatMapLatest in EventService.kt
fun getSelectedEventLive() = store.getEventID()
.filterNot { it.isBlank() }
.flatMapLatest { eventDao.get(it) }
this started as a new compose project
with the following code the intent is to change the text to the picked time. The code is commented where the behavior occurs
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
MyApplicationTestTheme {
// A surface container using the 'background' color from the theme
Surface(
modifier = Modifier.fillMaxSize(),
color = MaterialTheme.colors.background
) {
TimeCardButton(id = 1, symbol ="In", enabled=true,modifier = Modifier) { entry ->
Log.d("click", "$entry result")
}
}
}
}
}
}
data class TimeCardEntry(val id: Int = -1, var entry: String = "")
#Composable
fun TimeCardButton(
id: Int,
symbol: String,
enabled: Boolean = false,
modifier: Modifier,
onValueChange: (TimeCardEntry) -> Unit = {},
) {
// Value for storing time as a string
val timeState = remember {
mutableStateOf(TimeCardEntry(id, symbol))
}
val validState = remember {
timeState.value.entry.trim().isNotEmpty()
}
val mTime = remember { mutableStateOf(symbol) }
if (enabled) {
// Fetching local context
val mContext = LocalContext.current
// Declaring and initializing a calendar
val mCalendar = Calendar.getInstance()
val mHour = mCalendar[Calendar.HOUR_OF_DAY]
val mMinute = mCalendar[Calendar.MINUTE]
// Creating a TimePicker dialog
val mTimePickerDialog = TimePickerDialog(
mContext,
{ _, mHour: Int, mMinute: Int ->
timeState.value.entry = "$mHour:$mMinute"
mTime.value = "$mHour:$mMinute"
onValueChange(timeState.value)
}, mHour, mMinute, false
)
Box(
contentAlignment = Alignment.Center,
modifier = Modifier
.clip(CircleShape)
.then(modifier)
) {
TextButton(onClick = { mTimePickerDialog.show() }.also {
Log.d("click", "id $id clicked!") }) {
Column() {
// if I use just this it works [in changes to the time picked]
//Text(text = mTime.value)
// if i use both of these BOTH are set when the date picker is invoked
// if I just use the second one alone, the text never changes
Text(text = timeState.value.entry)
}
}
}
} else {
Box(
contentAlignment = Alignment.Center,
modifier = Modifier
.clip(CircleShape)
.then(modifier)
) {
Text(text = symbol, color =
MaterialTheme.colors.onBackground)
}
}
}
#Preview(showBackground = true)
#Composable
fun DefaultPreview() {
MyApplicationTestTheme {
}
}
First of all how to fix it:
Your problem basically is this. The easiest way to fix it would be to reassign the whole value of TimeState, not just entry by calling
timeState.value = timeState.value.copy(entry = "$mHour:$mMinute")
The reason it doesn't work with only the second one is that the change of a property doesn't trigger recomposition, even if the variable containing it is a mutableState. To fix (as outlined in the answers to the question linked above) this you either have to reassign the whole variable or make the parameter you want to observe observable (for example changing the String to State<String>)
PS: if you use by with mutableStateOf (i.e. val timeState = remember { mutableStateOf(TimeCardEntry(id, symbol)) }) you don't have to use .value every time. I find that a lot cleaner and more readable
I have a LazyRow. Everything works fine. I just want the items to be randomly rearranged every time this LazyRow is drawn on the screen. Here is my code:
LazyRow(
reverseLayout = true,
contentPadding = PaddingValues(top = twelveDp, end = eightDp)
) {
itemsIndexed(
items = featureUsersLazyPagingItems,
key = { _, featuredPerson ->
featuredPerson.uid
}
) { _, featuredUser ->
featuredUser?.let {
//Daw the age suggested People
DrawSuggestedPerson(featuredUser.toPersonUser(),) {
homeViewModel.deleteFeaturedUserFromLocalDb(featuredUser.uid)
}
}
}
featureUsersLazyPagingItems.apply {
when {
loadState.refresh is LoadState.Loading -> {
item {
ShowLazyColumnIsLoadingProgressBar()
}
}
loadState.append is LoadState.Loading -> {
item {
ShowLazyColumnIsLoadingProgressBar()
}
}
loadState.refresh is LoadState.Error -> {
val e = featureUsersLazyPagingItems.loadState.refresh as LoadState.Error
item {
LazyColumnErrorView(
message = e.error.localizedMessage!!,
onClickRetry = { retry() }
)
}
}
loadState.append is LoadState.Error -> {
val e = featureUsersLazyPagingItems.loadState.append as
LoadState.Error
item {
LazyColumnErrorView(
message = e.error.localizedMessage!!,
onClickRetry = { retry() }
)
}
}
}
}
So the LazyRow displays the same set of 30 or so items but only 3- 4 items are visible on screen, for a bit of variety, I would like the items to be re-arranged so that the user can see different items on the screen. Is there a way to achieve this?
You can shuffle your list inside remember, by doing this you're sure that during one view appearance your order will be the same, and it'll be shuffled on the next view appearance. I'm passing featureUsersLazyPagingItems as a key, so if featureUsersLazyPagingItems changes shuffledItems will be recalculated.
val shuffledItems = remember(featureUsersLazyPagingItems) {
featureUsersLazyPagingItems.shuffled()
}
The only problem of remember is that it'll be reset on screen rotation. Not sure if you need that, and if you wanna save state after rotation, you need to use rememberSaveable. As it can only store simple types, which your class isn't, you can store indices instead, like this:
val shuffledItemIndices = rememberSaveable(featureUsersLazyPagingItems) {
featureUsersLazyPagingItems.indices.shuffled()
}
val shuffledItems = remember(featureUsersLazyPagingItems, shuffledItemIndices) {
featureUsersLazyPagingItems.indices
.map(featureUsersLazyPagingItems::get)
}
I suggest you checkout out documentation for details of how state works in compose.