Что я пытаюсь сделать
Когда мое приложение запускается, я использую фрагмент, который использует AutoCompleteTextView и Places SDK для получения Place объекта когда пользователь делает выбор. Когда это происходит, я сохраняю выбранный объект Place (как объект WeatherLocation) через мой класс Repository в моей базе данных Room, вызывая repository.storeWeatherLocation(context,placeId), а затем при необходимости извлекаю сведения о погоде.
Что происходит
suspend fun storeWeatherLocationAsync вызывает fetchCurrentWeather() & fetchWeeklyWeather(), потому что из того, что я смог записать, переменная previousLocation равна нулю, несмотря на то, что инспектор базы данных показывает, что старые данные о погоде уже присутствует.
Cra sh детали
Мое приложение аварийно завершает работу, сообщая, что getCustomLocationLat() моего LocationProvider возвращает ноль (происходит в fetchCurrentWeather()). Дело в том, что выбранное пользователем местоположение успешно сохраняется в моей базе данных Room (проверено с помощью инспектора базы данных), так как эта функция возвращает ноль?
UPDATE :
Проведя дополнительное тестирование с помощью отладчика и logcat, я обнаружил, что данные WeatherLocation сохраняются в комнате при запуске приложения. Как только он падает, и я снова открываю его, эти данные снова становятся нулевыми. Что мне здесь не хватает? Я как-то удаляю предыдущие данные? Разве я на самом деле не кэширую это правильно в комнате?
Класс базы данных:
@Database(
entities = [CurrentWeatherEntry::class,WeekDayWeatherEntry::class,WeatherLocation::class],
version = 16
)
abstract class ForecastDatabase : RoomDatabase() {
abstract fun currentWeatherDao() : CurrentWeatherDao
abstract fun weekDayWeatherDao() : WeekDayWeatherDao
abstract fun weatherLocationDao() : WeatherLocationDao
// Used to make sure that the ForecastDatabase class will be a singleton
companion object {
// Volatile == all of the threads will have immediate access to this property
@Volatile private var instance:ForecastDatabase? = null
private val LOCK = Any() // dummy object for thread monitoring
operator fun invoke(context:Context) = instance ?: synchronized(LOCK) {
// If the instance var hasn't been initialized, call buildDatabase()
// and assign it the returned object from the function call (it)
instance ?: buildDatabase(context).also { instance = it }
}
/**
* Creates an instance of the ForecastDatabase class
* using Room.databaseBuilder().
*/
private fun buildDatabase(context: Context) =
Room.databaseBuilder(context.applicationContext,
ForecastDatabase::class.java, "forecast.db")
//.addMigrations(MIGRATION_2_3) // specify an explicit Migration Technique
.fallbackToDestructiveMigration()
.build()
}
}
Вот класс репозитория:
class ForecastRepositoryImpl(
private val currentWeatherDao: CurrentWeatherDao,
private val weekDayWeatherDao: WeekDayWeatherDao,
private val weatherLocationDao: WeatherLocationDao,
private val locationProvider: LocationProvider,
private val weatherNetworkDataSource: WeatherNetworkDataSource
) : ForecastRepository {
init {
weatherNetworkDataSource.apply {
// Persist downloaded data
downloadedCurrentWeatherData.observeForever { newCurrentWeather: CurrentWeatherResponse? ->
persistFetchedCurrentWeather(newCurrentWeather!!)
}
downloadedWeeklyWeatherData.observeForever { newWeeklyWeather: WeeklyWeatherResponse? ->
persistFetchedWeeklyWeather(newWeeklyWeather!!)
}
}
}
override suspend fun getCurrentWeather(): LiveData<CurrentWeatherEntry> {
return withContext(Dispatchers.IO) {
initWeatherData()
return@withContext currentWeatherDao.getCurrentWeather()
}
}
override suspend fun getWeekDayWeatherList(time: Long): LiveData<out List<WeekDayWeatherEntry>> {
return withContext(Dispatchers.IO) {
initWeatherData()
return@withContext weekDayWeatherDao.getFutureWeather(time)
}
}
override suspend fun getWeatherLocation(): LiveData<WeatherLocation> {
return withContext(Dispatchers.IO) {
return@withContext weatherLocationDao.getWeatherLocation()
}
}
private suspend fun initWeatherData() {
// retrieve the last weather location from room
val lastWeatherLocation = weatherLocationDao.getWeatherLocation().value
if (lastWeatherLocation == null ||
locationProvider.hasLocationChanged(lastWeatherLocation)
) {
fetchCurrentWeather()
fetchWeeklyWeather()
return
}
val lastFetchedTime = currentWeatherDao.getCurrentWeather().value?.zonedDateTime
if (isFetchCurrentNeeded(lastFetchedTime!!))
fetchCurrentWeather()
if (isFetchWeeklyNeeded())
fetchWeeklyWeather()
}
/**
* Checks if the current weather data should be re-fetched.
* @param lastFetchedTime The time at which the current weather data were last fetched
* @return True or false respectively
*/
private fun isFetchCurrentNeeded(lastFetchedTime: ZonedDateTime): Boolean {
val thirtyMinutesAgo = ZonedDateTime.now().minusMinutes(30)
return lastFetchedTime.isBefore(thirtyMinutesAgo)
}
/**
* Fetches the Current Weather data from the WeatherNetworkDataSource.
*/
private suspend fun fetchCurrentWeather() {
weatherNetworkDataSource.fetchCurrentWeather(
locationProvider.getPreferredLocationLat(),
locationProvider.getPreferredLocationLong()
)
}
private fun isFetchWeeklyNeeded(): Boolean {
val todayEpochTime = LocalDate.now().toEpochDay()
val futureWeekDayCount = weekDayWeatherDao.countFutureWeekDays(todayEpochTime)
return futureWeekDayCount < WEEKLY_FORECAST_DAYS_COUNT
}
private suspend fun fetchWeeklyWeather() {
weatherNetworkDataSource.fetchWeeklyWeather(
locationProvider.getPreferredLocationLat(),
locationProvider.getPreferredLocationLong()
)
}
override fun storeWeatherLocation(context:Context,placeId: String) {
GlobalScope.launch(Dispatchers.IO) {
storeWeatherLocationAsync(context,placeId)
}
}
override suspend fun storeWeatherLocationAsync(context: Context,placeId: String) {
var isFetchNeeded: Boolean // a flag variable
// Specify the fields to return.
val placeFields: List<Place.Field> =
listOf(Place.Field.ID, Place.Field.NAME,Place.Field.LAT_LNG)
// Construct a request object, passing the place ID and fields array.
val request = FetchPlaceRequest.newInstance(placeId, placeFields)
// Create the client
val placesClient = Places.createClient(context)
placesClient.fetchPlace(request).addOnSuccessListener { response ->
// Get the retrieved place object
val place = response.place
// Create a new WeatherLocation object using the place details
val newWeatherLocation = WeatherLocation(place.latLng!!.latitude,
place.latLng!!.longitude,place.name!!,place.id!!)
val previousLocation = weatherLocationDao.getWeatherLocation().value
if(previousLocation == null || ((newWeatherLocation.latitude != previousLocation.latitude) &&
(newWeatherLocation.longitude != previousLocation.longitude))) {
isFetchNeeded = true
// Store the weatherLocation in the database
persistWeatherLocation(newWeatherLocation)
// fetch the data
GlobalScope.launch(Dispatchers.IO) {
// fetch the weather data and wait for it to finish
withContext(Dispatchers.Default) {
if (isFetchNeeded) {
// fetch the weather data using the new location
fetchCurrentWeather()
fetchWeeklyWeather()
}
}
}
}
Log.d("REPOSITORY","storeWeatherLocationAsync : inside task called")
}.addOnFailureListener { exception ->
if (exception is ApiException) {
// Handle error with given status code.
Log.e("Repository", "Place not found: ${exception.statusCode}")
}
}
}
/**
* Caches the downloaded current weather data to the local
* database.
* @param fetchedCurrentWeather The most recently fetched current weather data
*/
private fun persistFetchedCurrentWeather(fetchedCurrentWeather: CurrentWeatherResponse) {
fetchedCurrentWeather.currentWeatherEntry.setTimezone(fetchedCurrentWeather.timezone)
// Using a GlobalScope since a Repository class doesn't have a lifecycle
GlobalScope.launch(Dispatchers.IO) {
currentWeatherDao.upsert(fetchedCurrentWeather.currentWeatherEntry)
}
}
/**
* Caches the selected location data to the local
* database.
* @param fetchedLocation The most recently fetched location data
*/
private fun persistWeatherLocation(fetchedLocation: WeatherLocation) {
GlobalScope.launch(Dispatchers.IO) {
weatherLocationDao.upsert(fetchedLocation)
}
}
/**
* Caches the downloaded weekly weather data to the local
* database.
* @param fetchedWeeklyWeather The most recently fetched weekly weather data
*/
private fun persistFetchedWeeklyWeather(fetchedWeeklyWeather: WeeklyWeatherResponse) {
fun deleteOldData() {
val time = LocalDate.now().toEpochDay()
weekDayWeatherDao.deleteOldEntries(time)
}
GlobalScope.launch(Dispatchers.IO) {
deleteOldData()
val weekDayEntriesList = fetchedWeeklyWeather.weeklyWeatherContainer.weekDayEntries
weekDayWeatherDao.insert(weekDayEntriesList)
}
}
}
, а вот Impl LocationProvider:
class LocationProviderImpl(
private val fusedLocationProviderClient: FusedLocationProviderClient,
context: Context,
private val locationDao: WeatherLocationDao
) : PreferenceProvider(context), LocationProvider {
private val appContext = context.applicationContext
override suspend fun hasLocationChanged(lastWeatherLocation: WeatherLocation): Boolean {
return try {
hasDeviceLocationChanged(lastWeatherLocation)
} catch (e:LocationPermissionNotGrantedException) {
false
}
}
/**
* Makes the required checks to determine whether the device's location has
* changed or not.
* @param lastWeatherLocation The last known user selected location
* @return true if the device location has changed or false otherwise
*/
private suspend fun hasDeviceLocationChanged(lastWeatherLocation: WeatherLocation): Boolean {
if(!isUsingDeviceLocation()) return false // we don't have location permissions or setting's disabled
val currentDeviceLocation = getLastDeviceLocationAsync().await()
?: return false
// Check if the old and new locations are far away enough that an update is needed
val comparisonThreshold = 0.03
return abs(currentDeviceLocation.latitude - lastWeatherLocation.latitude) > comparisonThreshold
&& abs(currentDeviceLocation.longitude - lastWeatherLocation.longitude) > comparisonThreshold
}
/**
* Checks if the app has the location permission, and if that's the case
* it will fetch the device's last saved location.
* @return The device's last saved location as a Deferred<Location?>
*/
@SuppressLint("MissingPermission")
private fun getLastDeviceLocationAsync(): Deferred<Location?> {
return if(hasLocationPermission())
fusedLocationProviderClient.lastLocation.asDeferredAsync()
else
throw LocationPermissionNotGrantedException()
}
/**
* Checks if the user has granted the location
* permission.
*/
private fun hasLocationPermission(): Boolean {
return ContextCompat.checkSelfPermission(appContext,
Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED
}
/**
* Returns the sharedPrefs value for the USE_DEVICE_LOCATION
* preference with a default value of "true".
*/
private fun isUsingDeviceLocation(): Boolean {
return preferences.getBoolean(USE_DEVICE_LOCATION_KEY,false)
}
private fun getCustomLocationLat() : Double {
val lat:Double? = locationDao.getWeatherLocation().value?.latitude
if(lat == null) Log.d("LOCATION_PROVIDER","lat is null = $lat")
return lat!!
}
private fun getCustomLocationLong():Double {
return locationDao.getWeatherLocation().value!!.longitude
}
override suspend fun getPreferredLocationLat(): Double {
if(isUsingDeviceLocation()) {
try {
val deviceLocation = getLastDeviceLocationAsync().await()
?: return getCustomLocationLat()
return deviceLocation.latitude
} catch (e:LocationPermissionNotGrantedException) {
return getCustomLocationLat()
}
} else {
return getCustomLocationLat()
}
}
override suspend fun getPreferredLocationLong(): Double {
if(isUsingDeviceLocation()) {
try {
val deviceLocation = getLastDeviceLocationAsync().await()
?: return getCustomLocationLong()
return deviceLocation.longitude
} catch (e:LocationPermissionNotGrantedException) {
return getCustomLocationLong()
}
} else {
return getCustomLocationLong()
}
}
}