sort folders alphabetically and run image slideshows

app/src/main/java/devs/org/calculator/activities/PreviewActivity.kt

@@ -4,6 +4,7 @@ import android.net.Uri
 import android.os.Bundle
 import android.os.Handler
 import android.os.Looper
+import android.view.View
 import android.view.WindowManager
 import android.widget.Toast
 import androidx.activity.enableEdgeToEdge
@@ -21,6 +22,7 @@ import devs.org.calculator.utils.DialogUtil
 import devs.org.calculator.utils.FileManager
 import devs.org.calculator.utils.PrefsUtil
 import devs.org.calculator.utils.SecurityUtils
+import kotlinx.coroutines.Runnable
 import kotlinx.coroutines.launch
 import java.io.File
 
@@ -40,6 +42,22 @@ class PreviewActivity : AppCompatActivity() {
     private val hiddenFileRepository: HiddenFileRepository by lazy {
         HiddenFileRepository(AppDatabase.getDatabase(this).hiddenFileDao())
     }
+    private var slideshowRunning = false
+    private val slideshowDelay = 2000L
+
+    private val slideshowRunner = object : Runnable {
+        override fun run() {
+            if (slideshowRunning) {
+                if (currentPosition + 1 >= files.size) {
+                    currentPosition = 0
+                } else {
+                    currentPosition += 1
+                }
+                binding.viewPager.setCurrentItem(currentPosition, true)
+                mainHandler.postDelayed(this, slideshowDelay)
+            }
+        }
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -134,6 +152,11 @@ class PreviewActivity : AppCompatActivity() {
 
         adapter = ImagePreviewAdapter(this, this)
         adapter.images = files
+        adapter.onSlideshowShouldStop = {
+            if (slideshowRunning) {
+                stopSlideshow()
+            }
+        }
         binding.viewPager.adapter = adapter
         if (currentPosition < files.size) {
             binding.viewPager.setCurrentItem(currentPosition, false)
@@ -179,6 +202,34 @@ class PreviewActivity : AppCompatActivity() {
                 currentPosition = position
             }
         })
+        if (filetype != FileManager.FileType.IMAGE) {
+            binding.startSlideshow.visibility = View.GONE
+        }
+        binding.startSlideshow.setOnClickListener {
+            startSlideshow()
+        }
+    }
+
+    private fun startSlideshow() {
+        if (!slideshowRunning) {
+            slideshowRunning = true
+            toggleToolbars()
+            mainHandler.postDelayed(slideshowRunner, slideshowDelay)
+            adapter.setImageZoomable(false)
+        }
+    }
+
+    private fun stopSlideshow() {
+        slideshowRunning = false
+        toggleToolbars()
+        mainHandler.removeCallbacks(slideshowRunner)
+        adapter.setImageZoomable(true)
+    }
+
+    private fun toggleToolbars() {
+        val visibility = if (slideshowRunning) View.GONE else View.VISIBLE
+        binding.toolbar.visibility = visibility
+        binding.footer.visibility = visibility
     }
 
     private fun handleDeleteFile() {

app/src/main/java/devs/org/calculator/adapters/ImagePreviewAdapter.kt

@@ -36,11 +36,14 @@ class ImagePreviewAdapter(
     private val hiddenFileRepository: HiddenFileRepository by lazy {
         HiddenFileRepository(AppDatabase.getDatabase(context).hiddenFileDao())
     }
+    private var canZoomOnImages: Boolean = true
 
     var images: List<File>
         get() = differ.currentList
         set(value) = differ.submitList(value)
 
+    var onSlideshowShouldStop: () -> Unit = {}
+
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ImageViewHolder {
         val binding = ViewpagerItemsBinding.inflate(LayoutInflater.from(context), parent, false)
         return ImageViewHolder(binding)
@@ -56,6 +59,11 @@ class ImagePreviewAdapter(
 
     override fun getItemCount(): Int = images.size
 
+    fun setImageZoomable(zoomable: Boolean) {
+        currentViewHolder?.setImageViewCanZoom(zoomable)
+        canZoomOnImages = zoomable
+    }
+
     private fun stopAndResetCurrentAudio() {
         currentViewHolder?.stopAndResetAudio()
         currentPlayingPosition = -1
@@ -153,6 +161,11 @@ class ImagePreviewAdapter(
                         binding.imageView.visibility = View.VISIBLE
                         binding.videoView.visibility = View.GONE
                         binding.audioBg.visibility = View.GONE
+                        binding.imageView.isZoomable = canZoomOnImages
+                        binding.imageView.doubleTapToZoom = canZoomOnImages
+                        binding.imageView.setOnClickListener {
+                            onSlideshowShouldStop()
+                        }
                         Glide.with(context)
                             .load(uri)
                             .error(R.drawable.encrypted)
@@ -181,6 +194,11 @@ class ImagePreviewAdapter(
                         binding.imageView.visibility = View.VISIBLE
                         binding.audioBg.visibility = View.GONE
                         binding.videoView.visibility = View.GONE
+                        binding.imageView.isZoomable = canZoomOnImages
+                        binding.imageView.doubleTapToZoom = canZoomOnImages
+                        binding.imageView.setOnClickListener {
+                            onSlideshowShouldStop()
+                        }
                         Glide.with(context)
                             .load(uri)
                             .error(R.drawable.encrypted)
@@ -193,6 +211,11 @@ class ImagePreviewAdapter(
             }
         }
 
+        fun setImageViewCanZoom(zoomEnabled: Boolean) {
+            binding.imageView.doubleTapToZoom = zoomEnabled
+            binding.imageView.isZoomable = zoomEnabled
+        }
+
         fun getFileFromUri(context: Context, uri: Uri): File? {
             return try {
                 val inputStream = context.contentResolver.openInputStream(uri)

app/src/main/java/devs/org/calculator/utils/FolderManager.kt

@@ -39,7 +39,7 @@ class FolderManager {
             directory.listFiles()?.filter { it.isDirectory && it.name != ".nomedia" } ?: emptyList()
         } else {
             emptyList()
-        }
+        }.sortedBy { it.name }
     }
 
     fun getFilesInFolder(folder: File): List<File> {

app/src/main/res/drawable/ic_slideshow.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="24dp"
+    android:viewportHeight="24"
+    android:viewportWidth="24"
+    android:width="24dp">
+    <path
+        android:fillColor="@color/svgTintColor"
+        android:pathData="M10,8v8l5,-4 -5,-4zM19,3L5,3c-1.1,0 -2,0.9 -2,2v14c0,1.1 0.9,2 2,2h14c1.1,0 2,-0.9 2,-2L21,5c0,-1.1 -0.9,-2 -2,-2zM19,19L5,19L5,5h14v14z"/>
+</vector>

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

@@ -14,6 +14,7 @@
         android:orientation="horizontal"
         android:gravity="center_vertical"
         android:paddingLeft="15dp"
+        android:paddingRight="15dp"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" >
         <androidx.appcompat.widget.AppCompatImageButton
@@ -26,11 +27,20 @@
             android:id="@+id/back"/>
         <TextView
             android:id="@+id/title"
-            android:layout_width="wrap_content"
+            android:layout_width="0dp"
             android:textSize="22sp"
             android:layout_height="wrap_content"
             android:textStyle="bold"
-            android:text="@string/preview_file"/>
+            android:text="@string/preview_file"
+            android:layout_weight="1"/>
+        <androidx.appcompat.widget.AppCompatImageButton
+            android:layout_width="40dp"
+            android:layout_height="40dp"
+            android:src="@drawable/ic_slideshow"
+            android:scaleType="fitCenter"
+            android:background="#00000000"
+            android:padding="8dp"
+            android:id="@+id/start_slideshow"/>
     </LinearLayout>
 
     <androidx.viewpager2.widget.ViewPager2
@@ -44,6 +54,7 @@
         app:layout_constraintTop_toTopOf="parent" />
 
     <LinearLayout
+        android:id="@+id/footer"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:gravity="center_horizontal"