add some cleanup on low memory

doesnt help by much but its here now

app/src/main/java/eu/kanade/tachiyomi/App.kt

@@ -20,7 +20,10 @@ import eu.kanade.tachiyomi.data.image.coil.CoilSetup
 import eu.kanade.tachiyomi.data.notification.Notifications
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
 import eu.kanade.tachiyomi.data.preference.asImmediateFlow
+import eu.kanade.tachiyomi.ui.library.LibraryPresenter
+import eu.kanade.tachiyomi.ui.recents.RecentsPresenter
 import eu.kanade.tachiyomi.ui.security.SecureActivityDelegate
+import eu.kanade.tachiyomi.ui.source.SourcePresenter
 import eu.kanade.tachiyomi.util.system.AuthenticatorUtil
 import eu.kanade.tachiyomi.util.system.notification
 import kotlinx.coroutines.flow.launchIn
@@ -120,6 +123,13 @@ open class App : Application(), DefaultLifecycleObserver {
         MultiDex.install(this)
     }
 
+    override fun onLowMemory() {
+        super.onLowMemory()
+        LibraryPresenter.onLowMemory()
+        RecentsPresenter.onLowMemory()
+        SourcePresenter.onLowMemory()
+    }
+
     protected open fun setupAcra() {
         initAcra {
             reportFormat = StringFormat.JSON

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt

@@ -1132,6 +1132,11 @@ class LibraryPresenter(
         private const val randomGroupOfTagsNormal = 1
         private const val randomGroupOfTagsNegate = 2
 
+        fun onLowMemory() {
+            lastLibraryItems = null
+            lastCategories = null
+        }
+
         suspend fun setSearchSuggestion(
             preferences: PreferencesHelper,
             db: DatabaseHelper,

app/src/main/java/eu/kanade/tachiyomi/ui/recents/RecentsPresenter.kt

@@ -505,6 +505,10 @@ class RecentsPresenter(
     companion object {
         private var lastRecents: List<RecentMangaItem>? = null
 
+        fun onLowMemory() {
+            lastRecents = null
+        }
+
         const val VIEW_TYPE_GROUP_ALL = 0
         const val VIEW_TYPE_UNGROUP_ALL = 1
         const val VIEW_TYPE_ONLY_HISTORY = 2

app/src/main/java/eu/kanade/tachiyomi/ui/source/SourcePresenter.kt

@@ -145,5 +145,10 @@ class SourcePresenter(
 
         private var lastSources: List<SourceItem>? = null
         private var lastUsedItemRem: SourceItem? = null
+
+        fun onLowMemory() {
+            lastSources = null
+            lastUsedItemRem = null
+        }
     }
 }