fix #270, temporarily show hidden files when opening a third party intent

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

@@ -21,6 +21,7 @@ import com.simplemobiletools.gallery.extensions.*
 import com.simplemobiletools.gallery.fragments.PhotoFragment
 import com.simplemobiletools.gallery.fragments.VideoFragment
 import com.simplemobiletools.gallery.fragments.ViewPagerFragment
+import com.simplemobiletools.gallery.helpers.IS_VIEW_INTENT
 import com.simplemobiletools.gallery.helpers.MEDIUM
 import com.simplemobiletools.gallery.models.Medium
 import kotlinx.android.synthetic.main.fragment_holder.*
@@ -119,6 +120,7 @@ open class PhotoVideoActivity : SimpleActivity(), ViewPagerFragment.FragmentList
 
     private fun sendViewPagerIntent(path: String) {
         Intent(this, ViewPagerActivity::class.java).apply {
+            putExtra(IS_VIEW_INTENT, true)
             putExtra(MEDIUM, path)
             startActivity(this)
         }

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

@@ -90,6 +90,10 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
             return
         }
 
+        if (intent.extras?.containsKey(IS_VIEW_INTENT) == true) {
+            config.temporarilyShowHidden = true
+        }
+
         mMedia = ArrayList<Medium>()
         showSystemUI()
 
@@ -107,6 +111,13 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
             view_pager.background = ColorDrawable(Color.BLACK)
     }
 
+    override fun onDestroy() {
+        super.onDestroy()
+        if (intent.extras?.containsKey(IS_VIEW_INTENT) == true) {
+            config.temporarilyShowHidden = false
+        }
+    }
+
     private fun setupOrientationEventListener() {
         mOrientationEventListener = object : OrientationEventListener(this, SensorManager.SENSOR_DELAY_NORMAL) {
             override fun onOrientationChanged(orientation: Int) {

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

@@ -33,6 +33,7 @@ val GET_VIDEO_INTENT = "get_video_intent"
 val GET_ANY_INTENT = "get_any_intent"
 val SET_WALLPAPER_INTENT = "set_wallpaper_intent"
 val DIRECTORIES = "directories2"
+val IS_VIEW_INTENT = "is_view_intent"
 
 val REQUEST_EDIT_IMAGE = 1
 val REQUEST_SET_WALLPAPER = 2