Persist last viewed item position on activity re-creation

Author: MHShetty

app/src/main/java/app/grapheneos/camera/ui/activities/InAppGallery.kt

@@ -64,12 +64,16 @@ class InAppGallery : AppCompatActivity() {
 
     private lateinit var rootView: View
 
+    private var lastViewedMediaPosition = 0
+
     companion object {
         const val INTENT_KEY_SECURE_MODE = "is_secure_mode"
         const val INTENT_KEY_VIDEO_ONLY_MODE = "video_only_mode"
         const val INTENT_KEY_LIST_OF_SECURE_MODE_CAPTURED_ITEMS = "secure_mode_items"
         const val INTENT_KEY_LAST_CAPTURED_ITEM = "last_captured_item"
 
+        const val LAST_VIEWED_ITEM_POSITION_KEY = "LAST_VIEWED_ITEM_POSITION_KEY"
+
         @SuppressLint("SimpleDateFormat")
         fun convertTime(time: Long, showTimeZone: Boolean = true): String {
             val date = Date(time)
@@ -431,6 +435,10 @@ class InAppGallery : AppCompatActivity() {
         snackBar = Snackbar.make(gallerySlider, "", Snackbar.LENGTH_LONG)
         gallerySlider.setPageTransformer(GSlideTransformer())
 
+        if (savedInstanceState != null) {
+            lastViewedMediaPosition = savedInstanceState.getInt(LAST_VIEWED_ITEM_POSITION_KEY, 0)
+        }
+
         val intent = this.intent
 
         val showVideosOnly = intent.getBooleanExtra(INTENT_KEY_VIDEO_ONLY_MODE, false)
@@ -523,6 +531,7 @@ class InAppGallery : AppCompatActivity() {
             }
             existingAdapter.notifyItemRangeInserted(1, items.size - 1)
         }
+        gallerySlider.setCurrentItem(lastViewedMediaPosition, false)
         showActionBar()
     }
 
@@ -560,4 +569,9 @@ class InAppGallery : AppCompatActivity() {
         snackBar.setText(msg)
         snackBar.show()
     }
+
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        outState.putInt(LAST_VIEWED_ITEM_POSITION_KEY, gallerySlider.currentItem)
+    }
 }