TabLayoutMediator has been re-instantiated, hopefully in a form that is less crash-prone. Crashes will also be handled now in StwParser.kt

app/src/main/java/com/denizk0461/studip/activity/FetcherActivity.kt

@@ -8,10 +8,9 @@ import android.webkit.WebView
 import android.webkit.WebViewClient
 import androidx.lifecycle.ViewModelProvider
 import com.denizk0461.studip.R
-import com.denizk0461.studip.data.getThemedColor
+import com.denizk0461.studip.data.showErrorSnackBar
 import com.denizk0461.studip.databinding.ActivityFetcherBinding
 import com.denizk0461.studip.viewmodel.FetcherViewModel
-import com.google.android.material.snackbar.Snackbar
 import java.io.IOException
 import java.net.URLDecoder
 
@@ -90,18 +89,8 @@ class FetcherActivity : Activity() {
 //                        finish()
 //                    }
                 } catch (e: IOException) {
-
                     // Let the user know that an error occurred
-                    Snackbar
+                    theme.showErrorSnackBar(binding.rootView, getString(R.string.fetch_error_snack))
-                        .make(
-                            binding.rootView,
-                            getString(R.string.fetch_error_snack),
-                            Snackbar.LENGTH_SHORT
-                        )
-                        // Set colours to signify an error
-                        .setBackgroundTint(theme.getThemedColor(R.attr.colorErrorContainer))
-                        .setTextColor(theme.getThemedColor(R.attr.colorOnErrorContainer))
-                        .show()
                 }
             }
         }

app/src/main/java/com/denizk0461/studip/data/Misc.kt

@@ -5,7 +5,10 @@ import android.content.res.Resources
 import android.util.TypedValue
 import android.widget.Toast
 import androidx.annotation.AttrRes
+import androidx.coordinatorlayout.widget.CoordinatorLayout
+import com.denizk0461.studip.R
 import com.denizk0461.studip.exception.AcademicQuarterNotApplicableException
+import com.google.android.material.snackbar.Snackbar
 import kotlin.jvm.Throws
 
 /**
@@ -42,6 +45,15 @@ fun showToast(context: Context, text: String) {
     Toast.makeText(context, text, Toast.LENGTH_SHORT).show()
 }
 
+fun Resources.Theme.showErrorSnackBar(view: CoordinatorLayout, text: String) {
+    Snackbar
+        .make(view, text, Snackbar.LENGTH_SHORT)
+        // Set colours to signify an error
+        .setBackgroundTint(getThemedColor(R.attr.colorErrorContainer))
+        .setTextColor(getThemedColor(R.attr.colorOnErrorContainer))
+        .show()
+}
+
 /**
  * Provides a conversion method between a timestamp ending in a full hour, and one with an academic
  * quarter applied.

app/src/main/java/com/denizk0461/studip/data/StwParser.kt

@@ -3,9 +3,12 @@ package com.denizk0461.studip.data
 import android.app.Application
 import com.denizk0461.studip.db.AppRepository
 import com.denizk0461.studip.model.*
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
 import org.jsoup.Jsoup
 import org.jsoup.nodes.Element
 import org.jsoup.select.Elements
+import kotlin.jvm.Throws
 
 /**
  * Parser class used for fetching and collecting canteen offers from the website of the
@@ -36,11 +39,14 @@ class StwParser(application: Application) {
     /**
      * Parses through a list of canteen plans and saves them to persistent storage.
      *
-     * @param onRefreshUpdate   action call for when an update on the status of the fetch is
-     *                          available
      * @param onFinish  action call for when the fetch has finished
+     * @param onError   action call for when an error has occurred
      */
-    fun parse(canteen: Int, onRefreshUpdate: (status: Int) -> Unit, onFinish: () -> Unit) {
+    suspend fun parse(
+        canteen: Int,
+        onFinish: () -> Unit,
+        onError: () -> Unit
+    ) {
         /*
          * Reset primary key values. This needs to be done in case this method is called multiple
          * times within the app's lifespan
@@ -65,12 +71,18 @@ class StwParser(application: Application) {
             else -> urlUniMensa
         }
 
-        // Delete all previous entries and start afresh
+        /*
-        repo.nukeOffers()
+         * Handle the fetch operation in an encompassing try-catch to prevent the app from crashing.
+         * User will be notified if an error occurs.
+         */
+        try {
 
             // Fetch offers from the chosen canteen
             val (dates, canteens, categories, items) = parseFromPage(link)
 
+            // Delete all previous entries and start afresh
+            repo.nukeOffers()
+
             // Save everything all at once into the database
             with(repo) {
                 insertDates(dates)
@@ -78,17 +90,28 @@ class StwParser(application: Application) {
                 insertCategories(categories)
                 insertItems(items)
             }
-            // TODO implement onRefresh(Int)
 
-        // Action call once all fetching activities have finished
+            // Call action to let the user know the fetch has finished
             onFinish()
+
+        } catch (e: RuntimeException) {
+            /*
+             * Call action to let the user know an error occurred. Do this on the main thread to
+             * access UI.
+             */
+            withContext(Dispatchers.Main) {
+                onError()
+            }
+        }
     }
 
     /**
      * Fetch and parse the plan of a specific canteen.
      *
      * @param url               link to the canteen to be scraped. Must be a subpage of stw-bremen.de
+     * @throws RuntimeException if something goes wrong during the fetch
      */
+    @Throws(RuntimeException::class)
     private fun parseFromPage(url: String): StwResults {
 
         val dates = mutableListOf<OfferDate>()
@@ -189,25 +212,34 @@ class StwParser(application: Application) {
                         // Retrieve the parent element holding the item's title and price
                         val tableRows = element.getElementsByTag("td")
 
-                        // Retrieve the dietary preferences the item meets
+                        /*
-                        val prefs = element
+                         * Retrieve the dietary preferences the item meets and parse them into a
+                         * string that can be inserted into the database.
+                         */
+                        val prefs = try {
+                            with(element
                                 .getElementsByClass("field field-name-field-food-types")[0]
+                            ) {
+                                DietaryPreferences.Object(
+                                    isFair = isDietaryPreferenceMet(imageLinkPrefFair),
+                                    isFish = isDietaryPreferenceMet(imageLinkPrefFish),
+                                    isPoultry = isDietaryPreferenceMet(imageLinkPrefPoultry),
+                                    isLamb = isDietaryPreferenceMet(imageLinkPrefLamb),
+                                    isVital = isDietaryPreferenceMet(imageLinkPrefVital),
+                                    isBeef = isDietaryPreferenceMet(imageLinkPrefBeef),
+                                    isPork = isDietaryPreferenceMet(imageLinkPrefPork),
+                                    isVegan = isDietaryPreferenceMet(imageLinkPrefVegan),
+                                    isVegetarian = isDietaryPreferenceMet(imageLinkPrefVegetarian),
+                                    isGame = isDietaryPreferenceMet(imageLinkPrefGame),
+                                )
+                            }
+                        } catch (e: IndexOutOfBoundsException) {
+                            DietaryPreferences.NONE_MET
+                        }
 
-                        // Parse the preferences into a string for the database
+                        val filteredText = getOrElse(orElse = Pair("", "")) {
-                        val prefString = DietaryPreferences.Object(
+                            tableRows[1].getFilteredText()
-                            isFair = prefs.isDietaryPreferenceMet(imageLinkPrefFair),
+                        }
-                            isFish = prefs.isDietaryPreferenceMet(imageLinkPrefFish),
-                            isPoultry = prefs.isDietaryPreferenceMet(imageLinkPrefPoultry),
-                            isLamb = prefs.isDietaryPreferenceMet(imageLinkPrefLamb),
-                            isVital = prefs.isDietaryPreferenceMet(imageLinkPrefVital),
-                            isBeef = prefs.isDietaryPreferenceMet(imageLinkPrefBeef),
-                            isPork = prefs.isDietaryPreferenceMet(imageLinkPrefPork),
-                            isVegan = prefs.isDietaryPreferenceMet(imageLinkPrefVegan),
-                            isVegetarian = prefs.isDietaryPreferenceMet(imageLinkPrefVegetarian),
-                            isGame = prefs.isDietaryPreferenceMet(imageLinkPrefGame),
-                        ).deconstruct()
-
-                        val filteredText = tableRows[1].getFilteredText()
 
                         // Save the item to its list
                         items.add(
@@ -216,7 +248,7 @@ class StwParser(application: Application) {
                                 categoryId,
                                 title = filteredText.first,
                                 price = tableRows.getTextOrEmpty(2),
-                                dietaryPreferences = prefString,
+                                dietaryPreferences = prefs.deconstruct(),
                                 allergens = filteredText.second,
                             )
                         )
@@ -300,7 +332,6 @@ class StwParser(application: Application) {
         /*
          * The Studierendenwerk's website lists allergens, but they are invisible, rendering them
          * pointless to the website user. As of now, this information is discarded in the app.
-         * TODO implement allergen functionality
          */
         while (text.contains("<sup>")) {
 
@@ -367,6 +398,12 @@ class StwParser(application: Application) {
         else -> "00" // shouldn't occur
     }
 
+    private fun <T> getOrElse(orElse: T, action: () -> T): T = try {
+        action()
+    } catch (e: Exception) {
+        orElse
+    }
+
     /**
      * Retrieves a text and adds <br> tags with line breaks.
      *
@@ -407,7 +444,7 @@ class StwParser(application: Application) {
     private val urlGW2 = "https://www.stw-bremen.de/de/cafeteria/gw2"
 //    private val urlGraz = "" // No link since there are only snacks on offer that are not listed online
     private val urlHSBNeustadt = "https://www.stw-bremen.de/de/mensa/neustadtswall"
-    private val urlHSBWerder = "https://www.stw-bremen.de/de/mensa/werderstra%C3%9Fe"
+    private val urlHSBWerder = "https://www.stw-bremen.de/de/mensa/werderstraße"
     private val urlHSBAirport = "https://www.stw-bremen.de/de/mensa/airport"
     private val urlHfK = "https://www.stw-bremen.de/de/mensa/interimsmensa-hfk"
     private val urlMensaBHV = "https://www.stw-bremen.de/de/mensa/bremerhaven"

app/src/main/java/com/denizk0461/studip/db/AppDAO.kt

@@ -67,20 +67,6 @@ interface AppDAO {
 
     /* --- canteen offers --- */
 
-    /**
-     * Retrieves all canteen offers. Objects will be joined through their primary/foreign keys from
-     * instances of OfferDate.kt, OfferCanteen.kt, OfferCategory.kt, and OfferItem.kt.
-     *
-     * @return all canteen offers exposed through a LiveData object
-     */
-    @get:Query(
-        "SELECT * FROM offer_item " +
-                "JOIN offer_category ON offer_item.categoryId = offer_category.id " +
-                "JOIN offer_canteen ON offer_category.canteenId = offer_canteen.id " +
-                "JOIN offer_date ON offer_category.dateId = offer_date.id"
-    )
-    val allOffers: LiveData<List<CanteenOffer>>
-
     /**
      * Retrieves all canteen offers that match given dietary preferences. Objects will be joined
      * through their primary/foreign keys from instances of OfferDate.kt, OfferCanteen.kt,
@@ -113,21 +99,13 @@ interface AppDAO {
     )
     fun getOffersByDay(day: Int): LiveData<List<CanteenOffer>>
 
-    /**
-     * Retrieves the amount of dates represented in the offers stored locally. Can be observed.
-     *
-     * @return  date count as LiveData
-     */
-    @Query("SELECT COUNT(*) FROM offer_date")
-    fun getDateCount(): LiveData<Int>
-
     /**
      * Retrieves all canteen offer date objects.
      *
      * @return a list of instances of canteen offer dates
      */
     @Query("SELECT * FROM offer_date ORDER BY id")
-    fun getDates(): List<OfferDate>
+    fun getDates(): LiveData<List<OfferDate>>
 
     /**
      * Deletes all dates from the database.

app/src/main/java/com/denizk0461/studip/db/AppRepository.kt

@@ -78,13 +78,6 @@ class AppRepository(app: Application) {
      */
     fun getCanteenOpeningHours(): String = dao.getCanteenOpeningHours()
 
-    /**
-     * Retrieves all canteen offers.
-     *
-     * @return all canteen offers exposed through a LiveData object
-     */
-    val allOffers: LiveData<List<CanteenOffer>> = dao.allOffers
-
     /**
      * Retrieves all canteen offers that match given day.
      *
@@ -92,13 +85,6 @@ class AppRepository(app: Application) {
      */
     fun getOffersByDay(day: Int): LiveData<List<CanteenOffer>> = dao.getOffersByDay(day)
 
-    /**
-     * Retrieves the amount of dates represented in the offers stored locally. Can be observed.
-     *
-     * @return  date count as LiveData
-     */
-    fun getDateCount(): LiveData<Int> = dao.getDateCount()
-
     /**
      * Updates a schedule element.
      *
@@ -122,7 +108,7 @@ class AppRepository(app: Application) {
      *
      * @return a list of instances of canteen offer dates
      */
-    fun getDates(): List<OfferDate> = dao.getDates()
+    fun getDates(): LiveData<List<OfferDate>> = dao.getDates()
 
     /**
      * Retrieves the regex string used to determine the user's dietary preferences, or, if no

app/src/main/java/com/denizk0461/studip/fragment/CanteenFragment.kt

@@ -9,6 +9,7 @@ import androidx.fragment.app.FragmentActivity
 import androidx.fragment.app.viewModels
 import com.denizk0461.studip.R
 import com.denizk0461.studip.adapter.CanteenOfferPageAdapter
+import com.denizk0461.studip.data.showErrorSnackBar
 import com.denizk0461.studip.databinding.FragmentCanteenBinding
 import com.denizk0461.studip.model.*
 import com.denizk0461.studip.sheet.TextSheet
@@ -37,17 +38,10 @@ class CanteenFragment : AppFragment() {
     // View model reference for providing access to the database
     private val viewModel: CanteenViewModel by viewModels()
 
-    // Elements in the canteen plan
-    private var elements: List<CanteenOffer> = listOf()
-
-    // Count of days displayed in the canteen plan
-    private var dateSize: Int = 0
-
-    // Used if no preference has been set or none can be found
-    private val emptyPreferenceRegex: String = ".........."
-
     private var openingHours = ""
 
+    private var dates: List<String> = listOf()
+
     // Instantiate the view binding
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
         _binding = FragmentCanteenBinding.inflate(inflater, container, false)
@@ -78,10 +72,10 @@ class CanteenFragment : AppFragment() {
                     binding.buttonCanteenPicker.text = getCurrentlySelectedCanteenName()
 
                     // Display to the user that the canteen plan will be refreshed
-                    binding.swipeRefreshLayout.isRefreshing = true
+//                    binding.swipeRefreshLayout.isRefreshing = true
 
                     // Refresh the canteen menu for the newly selected canteen
-//                    refresh()
+                    refresh()
                     true
                 }
                 inflate(R.menu.menu_canteens)
@@ -92,6 +86,7 @@ class CanteenFragment : AppFragment() {
         // Set currently selected canteen to the button
         binding.buttonCanteenPicker.text = getCurrentlySelectedCanteenName()
 
+        // Set up button to display info (most likely opening hours)
         binding.buttonInfo.setOnClickListener {
             openBottomSheet(
                 TextSheet(
@@ -104,7 +99,6 @@ class CanteenFragment : AppFragment() {
             )
         }
 
-
         // Assign a preference value to every button to filter for dietary preferences
         val chipMap = mapOf(
             binding.chipPrefFair to DietaryPreferences.WELFARE,
@@ -134,8 +128,7 @@ class CanteenFragment : AppFragment() {
                  * it removes the view before immediately adding it back, this method causes a
                  * flicker.
                  * TODO implement a more efficient / better-looking method
-                 * TODO order the chips alphabetically
+                 * TODO order the chips alphabetically?
-                 * TODO the refreshing ability stopped working
                  */
                 val index = binding.chipsPreference.indexOfChild(buttonView)
                 binding.chipsPreference.removeView(buttonView)
@@ -144,43 +137,25 @@ class CanteenFragment : AppFragment() {
         }
 
         // Set up the view pager's adapter
-        viewPagerAdapter = CanteenOfferPageAdapter(
+        viewPagerAdapter = CanteenOfferPageAdapter(activity as FragmentActivity)
-            activity as FragmentActivity,
-        )
 
-        viewModel.getDateCount().observe(viewLifecycleOwner) { dateCount ->
+        // Date count is observed to correctly set the amount of pages and the corresponding tabs
-            viewPagerAdapter.itemCount = dateCount
+        viewModel.getDates().observe(viewLifecycleOwner) { newDates ->
-            binding.swipeRefreshLayout.isRefreshing = false
+
+            // Retrieve the dates individually and store them for the tab mediator to use
+            dates = newDates.map { it.date }
+
+            // Let the adapter know of the new amount of dates (pages) to display
+            viewPagerAdapter.itemCount = dates.size
         }
 
         // Assign the adapter to the view pager
         binding.viewPager.adapter = viewPagerAdapter
 
-        // Set up LiveData observer to refresh the view on update
+        // Set up TabLayoutMediator to populate tabs
-//        viewModel.allOffers.observe(viewLifecycleOwner) { offers ->
+        TabLayoutMediator(binding.dayTabLayout, binding.viewPager) { tab, position ->
-//            // Update the element list stored in this fragment
+            tab.text = dates[position]
-//            elements = offers
+        }.attach()
-//
-//            // Group elements by category
-//            val groupedElements = offers.groupElements().distinct()
-//
-//            // Find all dates for which items are available
-//            val newDates = groupedElements.map { it.date }.distinct()
-//
-//            // Update the date count stored in this fragment
-//            dateSize = newDates.size
-//
-//            // Update the item list in the view pager's adapter
-////            viewPagerAdapter.setNewItems(groupedElements, dateSize)
-//
-//            // Set the text for the opening hours dialogue
-//            openingHours = viewModel.getCanteenOpeningHours()
-//
-//            binding.swipeRefreshLayout.isRefreshing = false
-//
-//            // Create and attach the tab layout for the ViewPager
-//            createTabLayoutMediator(newDates)
-//        }
 
         // Set up functions for when the user swipes to refresh the view
         binding.swipeRefreshLayout.setOnRefreshListener {
@@ -188,23 +163,6 @@ class CanteenFragment : AppFragment() {
         }
     }
 
-    /**
-     * Create and attach the object mediating the tabs for the view pager.
-     *
-     * TODO this is error-prone, likes to crash with an IndexOutOfBoundsException, and I have no
-     *  fucking idea why
-     *
-     * @param dates titles for the individual tabs
-     */
-    private fun createTabLayoutMediator(dates: List<String>) {
-        // Only attach the mediator if the list has items, otherwise an error would occur
-        if (dates.isNotEmpty()) {
-            TabLayoutMediator(binding.dayTabLayout, binding.viewPager) { tab, position ->
-                tab.text = dates[position]
-            }.attach()
-        }
-    }
-
     // Invalidate the view binding
     override fun onDestroyView() {
         super.onDestroyView()
@@ -223,7 +181,6 @@ class CanteenFragment : AppFragment() {
 
         // Update the view
         viewModel.registerDietaryPreferencesUpdate()
-//        viewPagerAdapter.setNewItems(elements.groupElements().distinct(), dateSize)
     }
 
     /**
@@ -258,38 +215,21 @@ class CanteenFragment : AppFragment() {
 
     /**
      * Downloads the canteen offers and refreshes them in the app.
-     * TODO handle SocketTimeoutException
      */
     private fun refresh() {
         // Retrieve new offers from the website(s)
-        viewModel.fetchOffers(viewModel.preferenceCanteen, onRefreshUpdate = { status ->
+        viewModel.fetchOffers(viewModel.preferenceCanteen, onFinish = {
-            // TODO refresh updates
-        }, onFinish = {
             /*
              * Tell the swipe refresh layout to stop refreshing.
-             * TODO if an exception is raised, this will not be fired. This must be changed
              */
-//                binding.swipeRefreshLayout.isRefreshing = false
+            binding.swipeRefreshLayout.isRefreshing = false
-//                createTabLayoutMediator()
+
+        }, onError = {
+            context?.theme?.showErrorSnackBar(
+                binding.snackbarContainer,
+                getString(R.string.canteen_fetch_error)
+            )
+            binding.swipeRefreshLayout.isRefreshing = false
         })
     }
-
-    /**
-     * Executed when an item has been clicked.
-     *
-     * @param offer item that has been clicked
-     */
-//    override fun onClick(offer: CanteenOfferGroupElement, category: String) {
-//        openBottomSheet(AllergenSheet(offer, category))
-//    }
-//
-//    /**
-//     * Executed when an item has been long-pressed.
-//     *
-//     * @param offer item that has been long-pressed
-//     * @return      whether the long press was successful
-//     */
-//    override fun onLongClick(offer: CanteenOfferGroupElement): Boolean {
-//        return false
-//    }
 }

app/src/main/java/com/denizk0461/studip/model/DietaryPreferences.kt

@@ -139,6 +139,8 @@ enum class DietaryPreferences(val value: String) {
 
         const val TEMPLATE_EMPTY: String = ".........."
 
+        val NONE_MET: Object = construct(TEMPLATE_EMPTY)
+
         /**
          * Constructs a DietaryPrefObject from a regex string. String must be 10 characters long.
          * A char equal to C_TRUE is treated as a true boolean value. Any other char is treated as a

app/src/main/java/com/denizk0461/studip/sheet/DevCodeSheet.kt

@@ -44,11 +44,11 @@ class DevCodeSheet(
              *
              * About the inks; they are safe (which is suspicious of me to say), just encoded so
              * people can't just look at the file and figure out all the codes! Of course, they're
-             * easily decoded, but who would go for that? You would have to be a pretty big nerd to
+             * easily decoded, but who would go for that? You would have to have a lot of time to
-             * do that. Then again, I was the one who encoded all of these links in the first place,
+             * waste to do that. Then again, I was the one who encoded all of these links in the
-             * so I suppose the joke's on me...
+             * first place, so I suppose the joke's on me...
              *
-             * If you're reading this – why?
+             * If you're reading this, I ask you – why?
              */
             when (binding.input.text.toString().uppercase()) {
                 "U1RST0JF".d64 -> launchLink("aHR0cHM6Ly95b3V0dS5iZS90S2k5Wi1mNnFYNA==".d64)
@@ -59,6 +59,9 @@ class DevCodeSheet(
                 "SE9ORVNU".d64 -> launchLink("aHR0cHM6Ly95b3V0dS5iZS9DSEg0OE5LUEFraw==".d64)
                 "QkJVT0s/".d64 -> launchLink("aHR0cHM6Ly95b3V0dS5iZS90Rm1PMm1TY0tHNA==".d64)
                 "SUhUU0Mq".d64 -> launchLink("aHR0cHM6Ly95b3V0dS5iZS85bXZ4SVdhWHZuWQ==".d64)
+                "SU5TQU5F".d64 -> launchLink("aHR0cHM6Ly95b3V0dS5iZS90NE9kYTlUZFYwbw==".d64)
+                "X0RSV05f".d64 -> launchLink("aHR0cHM6Ly95b3V0dS5iZS9SUVpUUy1CWjhtcw==".d64)
+                "TUFSR0Uh".d64 -> launchLink("aHR0cHM6Ly95b3V0dS5iZS8tbHFxRHZXRjQ1dw==".d64)
                 "NEVENT" -> { // nuke events
                     nukeEvents()
                     showToast(context, "Nuked all events")

app/src/main/java/com/denizk0461/studip/viewmodel/CanteenViewModel.kt

@@ -2,8 +2,11 @@ package com.denizk0461.studip.viewmodel
 
 import android.app.Application
 import androidx.lifecycle.LiveData
+import androidx.lifecycle.viewModelScope
 import com.denizk0461.studip.data.StwParser
 import com.denizk0461.studip.model.*
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
 
 /**
  * View model for [com.denizk0461.studip.fragment.CanteenFragment]
@@ -15,21 +18,12 @@ class CanteenViewModel(app: Application) : AppViewModel(app) {
     // Instantiate a parser, should the user want to refresh the canteen offers
     private val parser = StwParser(app)
 
-    /**
-     * Retrieves all Stud.IP events.
-     *
-     * @return all Stud.IP events exposed through a LiveData object
-     */
-    val allOffers: LiveData<List<CanteenOffer>> = repo.allOffers
-
-
-
     /**
      * Retrieves all canteen offer date objects.
      *
      * @return a list of instances of canteen offer dates
      */
-    fun getDates(): List<OfferDate> = returnBlocking { repo.getDates() }
+    fun getDates(): LiveData<List<OfferDate>> = repo.getDates()
 
     /**
      * Retrieves the opening hours of the canteen as a string.
@@ -42,24 +36,23 @@ class CanteenViewModel(app: Application) : AppViewModel(app) {
      * Fetch the canteen offers asynchronously. Updates will be provided through a LiveData object.
      *
      * @param canteen   canteen from which to fetch offers from
-     * @param onRefreshUpdate   action to execute when a status update is available
      * @param onFinish  action to execute when the operation has finished
+     * @param onError   action to execute when the operation encountered an error
      */
-    fun fetchOffers(canteen: Int, onRefreshUpdate: (status: Int) -> Unit, onFinish: () -> Unit) {
+    fun fetchOffers(
-        doAsync { parser.parse(canteen, onRefreshUpdate, onFinish) }
+        canteen: Int,
+        onFinish: () -> Unit,
+        onError: () -> Unit,
+    ) {
+        viewModelScope.launch(Dispatchers.IO) {
+            parser.parse(canteen, onFinish, onError)
+        }
     }
 
     fun registerDietaryPreferencesUpdate() {
         repo.dietaryPreferencesUpdate.postValue(repo.dietaryPreferencesUpdate.value?.plus(1))
     }
 
-    /**
-     * Retrieves the amount of dates represented in the offers stored locally. Can be observed.
-     *
-     * @return  date count as LiveData
-     */
-    fun getDateCount(): LiveData<Int> = repo.getDateCount()
-
     /**
      * Updates a given dietary preference to a new value.
      *
@@ -78,12 +71,6 @@ class CanteenViewModel(app: Application) : AppViewModel(app) {
      */
     fun getPreference(pref: DietaryPreferences): Boolean = repo.getBooleanPreference(pref)
 
-    /**
-     * This value determines whether the user wants to have allergens marked.
-     */
-    val preferenceAllergen: Boolean
-        get() = repo.getBooleanPreference(SettingsPreferences.ALLERGEN, defaultValue = true)
-
     /**
      * This value determines which canteen the user has selected.
      */

app/src/main/res/layout/fragment_canteen.xml

@@ -76,6 +76,14 @@
 
     </androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
 
+    <androidx.coordinatorlayout.widget.CoordinatorLayout
+        android:id="@+id/snackbar_container"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        app:layout_constraintBottom_toTopOf="@+id/scroll_view_chip"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"/>
+
     <HorizontalScrollView
         android:id="@+id/scroll_view_chip"
         android:layout_width="0dp"

app/src/main/res/layout/fragment_settings.xml

@@ -417,7 +417,7 @@
             android:layout_height="wrap_content"
             android:layout_gravity="center_horizontal"
             android:text="@string/with_love"
-            android:textSize="10sp"
+            android:textSize="8sp"
             android:layout_marginTop="4dp"
             android:layout_marginBottom="8dp"
             android:textAlignment="center"

app/src/main/res/values-de/strings.xml

@@ -20,6 +20,7 @@
     </string-array>
 
     <string name="fetch_error_snack">Ein Fehler ist aufgetreten!</string>
+    <string name="canteen_fetch_error">Mensaplan konnte nicht heruntergeladen werden!</string>
 
     <string name="save">Speichern</string>
     <string name="delete">Löschen</string>

app/src/main/res/values/strings.xml

@@ -20,6 +20,7 @@
     </string-array>
 
     <string name="fetch_error_snack">Something went wrong!</string>
+    <string name="canteen_fetch_error">Couldn\'t retrieve the canteen plan!</string>
 
     <string name="save">Save</string>
     <string name="delete">Delete</string>