improve portrait photos positioning

app/src/main/kotlin/com/simplemobiletools/gallery/pro/adapters/PortraitPhotosAdapter.kt

@@ -12,17 +12,15 @@ import com.bumptech.glide.request.RequestOptions
 import com.bumptech.glide.signature.ObjectKey
 import com.simplemobiletools.commons.extensions.getFileKey
 import com.simplemobiletools.gallery.pro.R
-import com.simplemobiletools.gallery.pro.extensions.realScreenSize
 import kotlinx.android.synthetic.main.portrait_photo_item.view.*
 import java.util.*
 
-class PortraitPhotosAdapter(val context: Context, val photos: ArrayList<String>, val itemClick: (Int) -> Unit) :
+class PortraitPhotosAdapter(val context: Context, val photos: ArrayList<String>, val sideElementWidth: Int, val itemClick: (Int) -> Unit) :
         RecyclerView.Adapter<PortraitPhotosAdapter.ViewHolder>() {
 
     private var currentSelection = photos.first()
     private var strokeBackground = context.resources.getDrawable(R.drawable.stroke_background)
-    private val screenWidth = context.realScreenSize.x
+    private val itemWidth = context.resources.getDimension(R.dimen.portrait_photos_stripe_height).toInt()
-    private val itemWidth = context.resources.getDimension(R.dimen.portrait_photos_stripe_height) + context.resources.getDimension(R.dimen.one_dp)
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
         holder.bindView(photos[position], position)
@@ -40,16 +38,16 @@ class PortraitPhotosAdapter(val context: Context, val photos: ArrayList<String>,
     inner class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
         fun bindView(photo: String, position: Int): View {
             itemView.apply {
-                if (position == 0) {
+                if (position == 0 || position == photos.size - 1) {
-                    portrait_photo_item_holder.setPadding(getStripeSidePadding(), 0, 0, 0)
+                    portrait_photo_item_thumbnail.layoutParams.width = sideElementWidth
-                } else if (position == photos.size - 1) {
+                } else {
-                    portrait_photo_item_holder.setPadding(0, 0, getStripeSidePadding(), 0)
+                    portrait_photo_item_thumbnail.layoutParams.width = itemWidth
                 }
 
-                portrait_photo_item_thumbnail.background = if (getCurrentPhoto() == photo) {
+                portrait_photo_item_thumbnail.background = if (photo.isEmpty() || getCurrentPhoto() != photo) {
-                    strokeBackground
-                } else {
                     null
+                } else {
+                    strokeBackground
                 }
 
                 val options = RequestOptions()
@@ -66,6 +64,4 @@ class PortraitPhotosAdapter(val context: Context, val photos: ArrayList<String>,
             return itemView
         }
     }
-
-    private fun getStripeSidePadding() = screenWidth / 2 - (itemWidth / 2).toInt()
 }

app/src/main/kotlin/com/simplemobiletools/gallery/pro/fragments/PhotoFragment.kt

@@ -56,6 +56,7 @@ import pl.droidsonroids.gif.InputSource
 import java.io.File
 import java.io.FileOutputStream
 import java.util.*
+import kotlin.math.ceil
 
 class PhotoFragment : ViewPagerFragment() {
     private val DEFAULT_DOUBLE_TAP_ZOOM = 2f
@@ -456,10 +457,33 @@ class PhotoFragment : ViewPagerFragment() {
 
         val files = File(mMedium.parentPath).listFiles()?.toMutableList() as? ArrayList<File>
         if (files != null) {
-            val paths = files.map { it.absolutePath }.toMutableList() as ArrayList<String>
+            val screenWidth = context!!.realScreenSize.x
-            val adapter = PortraitPhotosAdapter(context!!, paths) {
+            val itemWidth = context!!.resources.getDimension(R.dimen.portrait_photos_stripe_height) + context!!.resources.getDimension(R.dimen.one_dp)
+            val sideWidth = screenWidth / 2 - itemWidth / 2
+            val fakeItemsCnt = ceil(sideWidth / itemWidth.toDouble()).toInt()
 
+            val paths = ArrayList<String>()
+            for (i in 0 until fakeItemsCnt) {
+                paths.add("")
             }
+
+            files.forEach {
+                paths.add(it.absolutePath)
+            }
+
+            for (i in 0 until fakeItemsCnt) {
+                paths.add("")
+            }
+
+            var curWidth = itemWidth
+            while (curWidth < screenWidth) {
+                curWidth += itemWidth
+            }
+
+            val sideElementWidth = curWidth.toInt() - screenWidth
+            val adapter = PortraitPhotosAdapter(context!!, paths, sideElementWidth) {
+            }
+
             mView.photo_portrait_stripe.adapter = adapter
         }
     }

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

@@ -86,7 +86,7 @@
         android:layout_alignParentBottom="true"
         android:visibility="gone">
 
-        <com.simplemobiletools.commons.views.MyRecyclerView
+        <androidx.recyclerview.widget.RecyclerView
             android:id="@+id/photo_portrait_stripe"
             android:layout_width="match_parent"
             android:layout_height="match_parent"