From 2a41e4ce684375cebda83d03ec528060a45dadf3 Mon Sep 17 00:00:00 2001
From: arkon <eugcheung94@gmail.com>
Date: Mon, 27 Apr 2020 16:21:23 -0400
Subject: [PATCH] Fix BrowseSourceController losing scroll position when
 navigating back

---
 .../data/preference/PreferencesHelper.kt          |  2 --
 .../ui/source/browse/BrowseSourceController.kt    | 15 ++++++++-------
 .../tachiyomi/util/lang/CoroutinesExtensions.kt   |  9 ---------
 3 files changed, 8 insertions(+), 18 deletions(-)

diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt b/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt
index 68fa2e86a..47c1ecde6 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt
@@ -14,7 +14,6 @@ import eu.kanade.tachiyomi.data.preference.PreferenceKeys as Keys
 import eu.kanade.tachiyomi.data.preference.PreferenceValues as Values
 import eu.kanade.tachiyomi.data.track.TrackService
 import eu.kanade.tachiyomi.data.track.anilist.Anilist
-import eu.kanade.tachiyomi.util.lang.startWithCurrentValue
 import java.io.File
 import java.text.DateFormat
 import java.text.SimpleDateFormat
@@ -29,7 +28,6 @@ fun <T> RxPreference<T>.getOrDefault(): T = get() ?: defaultValue()!!
 fun <T> Preference<T>.asImmediateFlow(block: (value: T) -> Unit): Flow<T> {
     block(get())
     return asFlow()
-        .startWithCurrentValue { get() }
         .onEach { block(it) }
 }
 
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/source/browse/BrowseSourceController.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/source/browse/BrowseSourceController.kt
index 0a1ee1786..70723fab9 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/source/browse/BrowseSourceController.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/source/browse/BrowseSourceController.kt
@@ -48,6 +48,7 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.cancel
+import kotlinx.coroutines.flow.drop
 import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
@@ -190,12 +191,12 @@ open class BrowseSourceController(bundle: Bundle) :
         } else {
             (binding.catalogueView.inflate(R.layout.source_recycler_autofit) as AutofitRecyclerView).apply {
                 numColumnsScope = CoroutineScope(Job() + Dispatchers.Main)
-                getColumnsPreferenceForCurrentOrientation().asImmediateFlow {
-                    spanCount = it
-
-                    // Set the adapter again to recalculate the covers height
-                    adapter = this@BrowseSourceController.adapter
-                }
+                getColumnsPreferenceForCurrentOrientation().asImmediateFlow { spanCount = it }
+                    .drop(1)
+                    .onEach {
+                        // Set the adapter again to recalculate the covers height
+                        adapter = this@BrowseSourceController.adapter
+                    }
                     .launchIn(numColumnsScope!!)
 
                 (layoutManager as GridLayoutManager).spanSizeLookup = object : GridLayoutManager.SpanSizeLookup() {
@@ -452,7 +453,7 @@ open class BrowseSourceController(bundle: Bundle) :
      *
      * @return the preference.
      */
-    fun getColumnsPreferenceForCurrentOrientation(): Preference<Int> {
+    private fun getColumnsPreferenceForCurrentOrientation(): Preference<Int> {
         return if (resources?.configuration?.orientation == Configuration.ORIENTATION_PORTRAIT) {
             preferences.portraitColumns()
         } else {
diff --git a/app/src/main/java/eu/kanade/tachiyomi/util/lang/CoroutinesExtensions.kt b/app/src/main/java/eu/kanade/tachiyomi/util/lang/CoroutinesExtensions.kt
index 576493d7c..c126c028a 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/util/lang/CoroutinesExtensions.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/util/lang/CoroutinesExtensions.kt
@@ -6,8 +6,6 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.Job
-import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.onStart
 import kotlinx.coroutines.launch
 
 fun launchUI(block: suspend CoroutineScope.() -> Unit): Job =
@@ -19,10 +17,3 @@ fun launchIO(block: suspend CoroutineScope.() -> Unit): Job =
 @OptIn(ExperimentalCoroutinesApi::class)
 fun launchNow(block: suspend CoroutineScope.() -> Unit): Job =
     GlobalScope.launch(Dispatchers.Main, CoroutineStart.UNDISPATCHED, block)
-
-@OptIn(ExperimentalCoroutinesApi::class)
-fun <T> Flow<T>.startWithCurrentValue(block: () -> T?): Flow<T> {
-    return onStart {
-        block()?.let { emit(it) }
-    }
-}