Refactor RecyclerView adapters

app/src/main/java/sushi/hardcore/droidfs/adapters/ExplorerElementAdapter.kt

@@ -22,7 +22,6 @@ import sushi.hardcore.droidfs.explorers.ExplorerElement
 import sushi.hardcore.droidfs.util.PathUtils
 import java.text.DateFormat
 import java.util.*
-import kotlin.collections.HashSet
 
 class ExplorerElementAdapter(
     val activity: AppCompatActivity,
@@ -30,7 +29,7 @@ class ExplorerElementAdapter(
     val onExplorerElementClick: (Int) -> Unit,
     val onExplorerElementLongClick: (Int) -> Unit,
     val thumbnailMaxSize: Long,
-) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
+) : SelectableAdapter<ExplorerElement>() {
     val dateFormat: DateFormat = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.getDefault())
     var explorerElements = listOf<ExplorerElement>()
     @SuppressLint("NotifyDataSetChanged")
@@ -39,7 +38,6 @@ class ExplorerElementAdapter(
         thumbnailsCache?.evictAll()
         notifyDataSetChanged()
     }
-    var selectedItems: MutableSet<Int> = HashSet()
     var isUsingListLayout = true
     private var thumbnailsCache: LruCache<String, Bitmap>? = null
 
@@ -49,56 +47,32 @@ class ExplorerElementAdapter(
         }
     }
 
-    override fun getItemCount(): Int {
+    override fun getItems(): List<ExplorerElement> {
-        return explorerElements.size
+        return explorerElements
     }
 
-    private fun toggleSelection(position: Int): Boolean {
+    override fun toggleSelection(position: Int): Boolean {
-        if (!explorerElements[position].isParentFolder) {
+        return if (!explorerElements[position].isParentFolder) {
-            if (selectedItems.contains(position)) {
+            super.toggleSelection(position)
-                selectedItems.remove(position)
-            } else {
-                selectedItems.add(position)
-                return true
-            }
-        }
-        return false
-    }
-
-    private fun onItemClick(position: Int): Boolean {
-        onExplorerElementClick(position)
-        if (selectedItems.isNotEmpty()) {
-            return toggleSelection(position)
-        }
-        return false
-    }
-
-    private fun onItemLongClick(position: Int): Boolean {
-        onExplorerElementLongClick(position)
-        return toggleSelection(position)
-    }
-
-    fun selectAll() {
-        for (i in explorerElements.indices) {
-            if (!selectedItems.contains(i) && !explorerElements[i].isParentFolder) {
-                selectedItems.add(i)
-                notifyItemChanged(i)
-            }
-        }
-    }
-
-    fun unSelectAll(notifyChange: Boolean) {
-        if (notifyChange) {
-            val whatWasSelected = selectedItems
-            selectedItems = HashSet()
-            whatWasSelected.forEach {
-                notifyItemChanged(it)
-            }
         } else {
-            selectedItems.clear()
+            false
         }
     }
 
+    override fun onItemClick(position: Int): Boolean {
+        onExplorerElementClick(position)
+        return super.onItemClick(position)
+    }
+
+    override fun onItemLongClick(position: Int): Boolean {
+        onExplorerElementLongClick(position)
+        return super.onItemLongClick(position)
+    }
+
+    override fun isSelectable(position: Int): Boolean {
+        return !explorerElements[position].isParentFolder
+    }
+
     open class ExplorerElementViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
         private val textElementName by lazy {
             itemView.findViewById<TextView>(R.id.text_element_name)
@@ -116,21 +90,9 @@ class ExplorerElementAdapter(
             itemView.findViewById(R.id.selectable_container)
         }
 
-        protected fun setBackground(isSelected: Boolean) {
-            itemView.setBackgroundResource(if (isSelected) { R.color.itemSelected } else { 0 })
-        }
-
         open fun bind(explorerElement: ExplorerElement, position: Int) {
             textElementName.text = explorerElement.name
-            (bindingAdapter as ExplorerElementAdapter?)?.let { adapter ->
+            (bindingAdapter as ExplorerElementAdapter?)?.setSelectable(selectableContainer, itemView, position)
-                selectableContainer.setOnClickListener {
-                    setBackground(adapter.onItemClick(position))
-                }
-                selectableContainer.setOnLongClickListener {
-                    setBackground(adapter.onItemLongClick(position))
-                    true
-                }
-            }
         }
     }
 
@@ -141,7 +103,6 @@ class ExplorerElementAdapter(
             (bindingAdapter as ExplorerElementAdapter?)?.let {
                 textElementMtime.text = it.dateFormat.format(explorerElement.mTime)
             }
-            setBackground(isSelected)
         }
     }
 

app/src/main/java/sushi/hardcore/droidfs/adapters/SelectableAdapter.kt

@@ -0,0 +1,76 @@
+package sushi.hardcore.droidfs.adapters
+
+import android.view.View
+import androidx.recyclerview.widget.RecyclerView
+import sushi.hardcore.droidfs.R
+
+abstract class SelectableAdapter<T> : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
+    var selectedItems: MutableSet<Int> = HashSet()
+
+    protected abstract fun getItems(): List<T>
+
+    override fun getItemCount(): Int {
+        return getItems().size
+    }
+
+    protected open fun toggleSelection(position: Int): Boolean {
+        return if (selectedItems.contains(position)) {
+            selectedItems.remove(position)
+            false
+        } else {
+            selectedItems.add(position)
+            true
+        }
+    }
+
+    protected open fun onItemClick(position: Int): Boolean {
+        if (selectedItems.isNotEmpty()) {
+            return toggleSelection(position)
+        }
+        return false
+    }
+
+    protected open fun onItemLongClick(position: Int): Boolean {
+        return toggleSelection(position)
+    }
+
+    protected open fun isSelectable(position: Int): Boolean {
+        return true
+    }
+
+    fun selectAll() {
+        for (i in getItems().indices) {
+            if (!selectedItems.contains(i) && isSelectable(i)) {
+                selectedItems.add(i)
+                notifyItemChanged(i)
+            }
+        }
+    }
+
+    fun unSelectAll(notifyChange: Boolean) {
+        if (notifyChange) {
+            val whatWasSelected = selectedItems
+            selectedItems = HashSet()
+            whatWasSelected.forEach {
+                notifyItemChanged(it)
+            }
+        } else {
+            selectedItems.clear()
+        }
+    }
+
+    private fun setBackground(rootView: View, isSelected: Boolean) {
+        rootView.setBackgroundResource(if (isSelected) R.color.itemSelected else 0)
+    }
+
+    protected fun setSelectable(element: View, rootView: View, position: Int) {
+        element.setOnClickListener {
+            setBackground(rootView, onItemClick(position))
+        }
+        element.setOnLongClickListener {
+            setBackground(rootView, onItemLongClick(position))
+            true
+        }
+        setBackground(rootView, selectedItems.contains(position))
+    }
+}

app/src/main/java/sushi/hardcore/droidfs/adapters/VolumeAdapter.kt

@@ -19,15 +19,18 @@ class VolumeAdapter(
     private val showReadOnly: Boolean,
     private val onVolumeItemClick: (Volume, Int) -> Unit,
     private val onVolumeItemLongClick: () -> Unit,
-) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
+) : SelectableAdapter<Volume>() {
     private val inflater: LayoutInflater = LayoutInflater.from(context)
     lateinit var volumes: List<Volume>
-    var selectedItems: MutableSet<Int> = HashSet()
 
     init {
         reloadVolumes()
     }
 
+    override fun getItems(): List<Volume> {
+        return volumes
+    }
+
     private fun reloadVolumes() {
         volumes = if (showReadOnly) {
             volumeDatabase.getVolumes()
@@ -36,28 +39,19 @@ class VolumeAdapter(
         }
     }
 
-    private fun toggleSelection(position: Int): Boolean {
+    override fun onItemClick(position: Int): Boolean {
-        return if (selectedItems.contains(position)) {
-            selectedItems.remove(position)
-            false
-        } else {
-            selectedItems.add(position)
-            true
-        }
-    }
-
-    private fun onItemClick(position: Int): Boolean {
         onVolumeItemClick(volumes[position], position)
-        if (allowSelection && selectedItems.isNotEmpty()) {
+        return if (allowSelection) {
-            return toggleSelection(position)
+            super.onItemClick(position)
+        } else {
+            false
         }
-        return false
     }
 
-    private fun onItemLongClick(position: Int): Boolean {
+    override fun onItemLongClick(position: Int): Boolean {
         onVolumeItemLongClick()
         return if (allowSelection)
-            toggleSelection(position)
+            super.onItemLongClick(position)
         else
             false
     }
@@ -67,27 +61,6 @@ class VolumeAdapter(
         notifyItemChanged(position)
     }
 
-    fun selectAll() {
-        for (i in volumes.indices) {
-            if (!selectedItems.contains(i)) {
-                selectedItems.add(i)
-                notifyItemChanged(i)
-            }
-        }
-    }
-
-    fun unSelectAll(notifyChange: Boolean) {
-        if (notifyChange) {
-            val whatWasSelected = selectedItems
-            selectedItems = HashSet()
-            whatWasSelected.forEach {
-                notifyItemChanged(it)
-            }
-        } else {
-            selectedItems.clear()
-        }
-    }
-
     fun refresh() {
         reloadVolumes()
         unSelectAll(true)
@@ -95,10 +68,6 @@ class VolumeAdapter(
 
     inner class VolumeViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
 
-        private fun setBackground(isSelected: Boolean) {
-            itemView.setBackgroundResource(if (isSelected) R.color.itemSelected else 0)
-        }
-
         fun bind(position: Int) {
             val volume = volumes[position]
             itemView.findViewById<TextView>(R.id.text_volume_name).text = volume.shortName
@@ -123,18 +92,7 @@ class VolumeAdapter(
                     visibility = View.VISIBLE
                 }
             }
-            (bindingAdapter as VolumeAdapter?)?.let { adapter ->
+            setSelectable(itemView.findViewById<LinearLayout>(R.id.selectable_container), itemView, layoutPosition)
-                itemView.findViewById<LinearLayout>(R.id.selectable_container).apply {
-                    setOnClickListener {
-                        setBackground(adapter.onItemClick(layoutPosition))
-                    }
-                    setOnLongClickListener {
-                        setBackground(adapter.onItemLongClick(layoutPosition))
-                        true
-                    }
-                }
-            }
-            setBackground(selectedItems.contains(position))
         }
     }
 
@@ -146,8 +104,4 @@ class VolumeAdapter(
     override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
         (holder as VolumeViewHolder).bind(position)
     }
-
-    override fun getItemCount(): Int {
-        return volumes.size
-    }
 }