feat: show the proper message in the custom picker when all images are either uploaded or marked. (commons-app#6095)

* feat: show the message "Congratulations, all pictures in this album have been either uploaded or marked as not for upload." in the custom picker when all images are either uploaded or marked.

* refactor: fix indentation in the code

* refactor: replace LiveData with StateFlow

* fix: fixed the bug that was causing one ImageFragment testcase to fail.

* fix: fixed the Congratulation message being shown for a brief moment while switching off the switch

* refactor: move hardcoded string to strings.xml.

* docs: add comment to clarify visibility logic in ImageFragment

---------

Co-authored-by: Nicolas Raoul <nicolas.raoul@gmail.com>

Author: yuvraj-coder1

app/src/main/java/fr/free/nrw/commons/customselector/ui/adapter/ImageAdapter.kt

@@ -24,6 +24,7 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.MainScope
 import kotlinx.coroutines.cancel
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.launch
 import java.util.TreeMap
 import kotlin.collections.ArrayList
@@ -103,6 +104,18 @@ class ImageAdapter(
      */
     private var imagePositionAsPerIncreasingOrder = 0
 
+    /**
+     * Stores the number of images currently visible on the screen
+     */
+    private val _currentImagesCount = MutableStateFlow(0)
+    val currentImagesCount = _currentImagesCount
+
+    /**
+     * Stores whether images are being loaded or not
+     */
+    private val _isLoadingImages = MutableStateFlow(false)
+    val isLoadingImages = _isLoadingImages
+
     /**
      * Coroutine Dispatchers and Scope.
      */
@@ -184,8 +197,12 @@ class ImageAdapter(
                     // If the position is not already visited, that means the position is new then
                     // finds the next actionable image position from all images
                     if (!alreadyAddedPositions.contains(position)) {
-                        processThumbnailForActionedImage(holder, position, uploadingContributionList)
-
+                        processThumbnailForActionedImage(
+                            holder,
+                            position,
+                            uploadingContributionList
+                        )
+                        _isLoadingImages.value = false
                         // If the position is already visited, that means the image is already present
                         // inside map, so it will fetch the image from the map and load in the holder
                     } else {
@@ -231,6 +248,7 @@ class ImageAdapter(
         position: Int,
         uploadingContributionList: List<Contribution>,
     ) {
+        _isLoadingImages.value = true
         val next =
             imageLoader.nextActionableImage(
                 allImages,
@@ -252,6 +270,7 @@ class ImageAdapter(
                 actionableImagesMap[next] = allImages[next]
                 alreadyAddedPositions.add(imagePositionAsPerIncreasingOrder)
                 imagePositionAsPerIncreasingOrder++
+                _currentImagesCount.value = imagePositionAsPerIncreasingOrder
                 Glide
                     .with(holder.image)
                     .load(allImages[next].uri)
@@ -267,6 +286,7 @@ class ImageAdapter(
             reachedEndOfFolder = true
             notifyItemRemoved(position)
         }
+        _isLoadingImages.value = false
     }
 
     /**
@@ -372,6 +392,7 @@ class ImageAdapter(
         emptyMap: TreeMap<Int, Image>,
         uploadedImages: List<Contribution> = ArrayList(),
     ) {
+        _isLoadingImages.value = true
         allImages = fixedImages
         val oldImageList: ArrayList<Image> = images
         val newImageList: ArrayList<Image> = ArrayList(newImages)
@@ -382,6 +403,7 @@ class ImageAdapter(
         reachedEndOfFolder = false
         selectedImages = ArrayList()
         imagePositionAsPerIncreasingOrder = 0
+        _currentImagesCount.value = imagePositionAsPerIncreasingOrder
         val diffResult =
             DiffUtil.calculateDiff(
                 ImagesDiffCallback(oldImageList, newImageList),
@@ -441,6 +463,7 @@ class ImageAdapter(
                 val entry = iterator.next()
                 if (entry.value == image) {
                     imagePositionAsPerIncreasingOrder -= 1
+                    _currentImagesCount.value = imagePositionAsPerIncreasingOrder
                     iterator.remove()
                     alreadyAddedPositions.removeAt(alreadyAddedPositions.size - 1)
                     notifyItemRemoved(index)

app/src/main/java/fr/free/nrw/commons/customselector/ui/selector/ImageFragment.kt

@@ -12,8 +12,12 @@ import android.widget.ProgressBar
 import android.widget.Switch
 import androidx.appcompat.app.AlertDialog
 import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.core.view.isVisible
+import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.Observer
 import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import fr.free.nrw.commons.contributions.Contribution
@@ -38,6 +42,10 @@ import fr.free.nrw.commons.theme.BaseActivity
 import fr.free.nrw.commons.upload.FileProcessor
 import fr.free.nrw.commons.upload.FileUtilsWrapper
 import io.reactivex.schedulers.Schedulers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.launch
 import java.util.TreeMap
 import javax.inject.Inject
 import kotlin.collections.ArrayList
@@ -80,6 +88,12 @@ class ImageFragment :
      */
     var allImages: ArrayList<Image> = ArrayList()
 
+    /**
+     * Keeps track of switch state
+     */
+    private val _switchState = MutableStateFlow(false)
+    val switchState = _switchState.asStateFlow()
+
     /**
      * View model Factory.
      */
@@ -214,7 +228,11 @@ class ImageFragment :
 
         switch = binding?.switchWidget
         switch?.visibility = View.VISIBLE
-        switch?.setOnCheckedChangeListener { _, isChecked -> onChangeSwitchState(isChecked) }
+        _switchState.value = switch?.isChecked ?: false
+        switch?.setOnCheckedChangeListener { _, isChecked ->
+            onChangeSwitchState(isChecked)
+            _switchState.value = isChecked
+        }
         selectorRV = binding?.selectorRv
         loader = binding?.loader
         progressLayout = binding?.progressLayout
@@ -234,6 +252,28 @@ class ImageFragment :
         return binding?.root
     }
 
+    /**
+     * onViewCreated
+     * Updates empty text view visibility based on image count, switch state, and loading status.
+     */
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        viewLifecycleOwner.lifecycleScope.launch {
+            repeatOnLifecycle(Lifecycle.State.STARTED) {
+                combine(
+                    imageAdapter.currentImagesCount,
+                    switchState,
+                    imageAdapter.isLoadingImages
+                ) { imageCount, isChecked, isLoadingImages ->
+                    Triple(imageCount, isChecked, isLoadingImages)
+                }.collect { (imageCount, isChecked, isLoadingImages) ->
+                    binding?.allImagesUploadedOrMarked?.isVisible =
+                        !isLoadingImages && !isChecked && imageCount == 0 && (switch?.isVisible == true)
+                }
+            }
+        }
+    }
+
     private fun onChangeSwitchState(checked: Boolean) {
         if (checked) {
             showAlreadyActionedImages = true

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

@@ -49,6 +49,20 @@
     app:layout_constraintStart_toStartOf="parent"
     app:layout_constraintTop_toTopOf="parent" />
 
+  <TextView
+    android:id="@+id/all_images_uploaded_or_marked"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:visibility="gone"
+    android:textSize="16sp"
+    android:padding="@dimen/standard_gap"
+    android:textColor="@color/text_color_selector"
+    android:text="@string/congratulations_all_pictures_in_this_album_have_been_either_uploaded_or_marked_as_not_for_upload"
+    app:layout_constraintTop_toTopOf="parent"
+    app:layout_constraintBottom_toBottomOf="parent"
+    app:layout_constraintEnd_toEndOf="parent"
+    app:layout_constraintStart_toStartOf="parent"
+    />
 
   <ProgressBar
     android:id="@+id/loader"

app/src/main/res/values/strings.xml

@@ -867,5 +867,6 @@ Upload your first media by tapping on the add button.</string>
   <string name="account_vanish_request_confirm"><![CDATA[Vanishing is a <b>last resort</b> and should <b>only be used when you wish to stop editing forever</b> and also to hide as many of your past associations as possible.<br/><br/>Account deletion on Wikimedia Commons is done by changing your account name to make it so others cannot recognize your contributions in a process called account vanishing. <b>Vanishing does not guarantee complete anonymity or remove contributions to the projects</b>.]]></string>
   <string name="caption">Caption</string>
   <string name="caption_copied_to_clipboard">Caption copied to clipboard</string>
+  <string name="congratulations_all_pictures_in_this_album_have_been_either_uploaded_or_marked_as_not_for_upload">Congratulations, all pictures in this album have been either uploaded or marked as not for upload.</string>
 
 </resources>