add an option to loop slideshows

app/src/main/kotlin/com/simplemobiletools/gallery/activities/ViewPagerActivity.kt

@@ -301,8 +301,7 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
                 view_pager.endFakeDrag()
 
                 if (view_pager.currentItem == oldPosition) {
-                    stopSlideshow()
+                    slideshowEnded(forward)
-                    toast(R.string.slideshow_ended)
                 }
             }
 
@@ -330,6 +329,19 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
         animator.start()
     }
 
+    private fun slideshowEnded(forward: Boolean) {
+        if (config.loopSlideshow) {
+            if (forward) {
+                view_pager.setCurrentItem(0, false)
+            } else {
+                view_pager.setCurrentItem(view_pager.adapter!!.count - 1, false)
+            }
+        } else {
+            stopSlideshow()
+            toast(R.string.slideshow_ended)
+        }
+    }
+
     private fun stopSlideshow() {
         if (mIsSlideshowActive) {
             showSystemUI()

app/src/main/kotlin/com/simplemobiletools/gallery/dialogs/SlideshowDialog.kt

@@ -61,6 +61,11 @@ class SlideshowDialog(val activity: SimpleActivity, val callback: () -> Unit) {
                 interval_value.clearFocus()
                 move_backwards.toggle()
             }
+
+            loop_slideshow_holder.setOnClickListener {
+                interval_value.clearFocus()
+                loop_slideshow.toggle()
+            }
         }
         setupValues()
 
@@ -93,6 +98,7 @@ class SlideshowDialog(val activity: SimpleActivity, val callback: () -> Unit) {
             random_order.isChecked = config.slideshowRandomOrder
             use_fade.isChecked = config.slideshowUseFade
             move_backwards.isChecked = config.slideshowMoveBackwards
+            loop_slideshow.isChecked = config.loopSlideshow
         }
     }
 
@@ -109,6 +115,7 @@ class SlideshowDialog(val activity: SimpleActivity, val callback: () -> Unit) {
             slideshowRandomOrder = view.random_order.isChecked
             slideshowUseFade = view.use_fade.isChecked
             slideshowMoveBackwards = view.move_backwards.isChecked
+            loopSlideshow = view.loop_slideshow.isChecked
         }
     }
 }

app/src/main/kotlin/com/simplemobiletools/gallery/helpers/Config.kt

@@ -272,4 +272,8 @@ class Config(context: Context) : BaseConfig(context) {
     var slideshowMoveBackwards: Boolean
         get() = prefs.getBoolean(SLIDESHOW_MOVE_BACKWARDS, false)
         set(slideshowMoveBackwards) = prefs.edit().putBoolean(SLIDESHOW_MOVE_BACKWARDS, slideshowMoveBackwards).apply()
+
+    var loopSlideshow: Boolean
+        get() = prefs.getBoolean(SLIDESHOW_LOOP, false)
+        set(loopSlideshow) = prefs.edit().putBoolean(SLIDESHOW_LOOP, loopSlideshow).apply()
 }

app/src/main/kotlin/com/simplemobiletools/gallery/helpers/Constants.kt

@@ -45,6 +45,7 @@ val SLIDESHOW_INCLUDE_GIFS = "slideshow_include_gifs"
 val SLIDESHOW_RANDOM_ORDER = "slideshow_random_order"
 val SLIDESHOW_USE_FADE = "slideshow_use_fade"
 val SLIDESHOW_MOVE_BACKWARDS = "slideshow_move_backwards"
+val SLIDESHOW_LOOP = "loop_slideshow"
 val SLIDESHOW_DEFAULT_INTERVAL = 5
 val SLIDESHOW_SCROLL_DURATION = 500L
 

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

@@ -161,5 +161,26 @@
                 android:text="@string/move_backwards"/>
 
         </RelativeLayout>
+
+        <RelativeLayout
+            android:id="@+id/loop_slideshow_holder"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_below="@+id/move_backwards_holder"
+            android:background="?attr/selectableItemBackground"
+            android:paddingBottom="@dimen/activity_margin"
+            android:paddingLeft="@dimen/medium_margin"
+            android:paddingStart="@dimen/medium_margin"
+            android:paddingTop="@dimen/activity_margin">
+
+            <com.simplemobiletools.commons.views.MySwitchCompat
+                android:id="@+id/loop_slideshow"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:background="@null"
+                android:clickable="false"
+                android:text="@string/loop_slideshow"/>
+
+        </RelativeLayout>
     </RelativeLayout>
 </ScrollView>