avoid refreshing Widgets fragment if nothing changed

app/src/main/kotlin/com/simplemobiletools/launcher/adapters/WidgetsAdapter.kt

@@ -22,7 +22,7 @@ import kotlinx.android.synthetic.main.item_widget_preview.view.*
 
 class WidgetsAdapter(
     val activity: SimpleActivity,
-    val widgetListItems: ArrayList<WidgetsListItem>,
+    var widgetListItems: ArrayList<WidgetsListItem>,
     val widgetsFragmentListener: WidgetsFragmentListener
 ) : RecyclerView.Adapter<WidgetsAdapter.ViewHolder>() {
 
@@ -113,6 +113,15 @@ class WidgetsAdapter(
         }
     }
 
+    fun updateItems(newItems: ArrayList<WidgetsListItem>) {
+        val oldSum = widgetListItems.sumOf { it.getHashToCompare() }
+        val newSum = newItems.sumOf { it.getHashToCompare() }
+        if (oldSum != newSum) {
+            widgetListItems = newItems
+            notifyDataSetChanged()
+        }
+    }
+
     inner class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
         fun bindView(widgetListItem: WidgetsListItem, callback: (itemView: View, adapterPosition: Int) -> Unit) {
             itemView.apply {

app/src/main/kotlin/com/simplemobiletools/launcher/fragments/WidgetsFragment.kt

@@ -150,9 +150,14 @@ class WidgetsFragment(context: Context, attributeSet: AttributeSet) : MyFragment
 
     private fun setupAdapter(widgetsListItems: ArrayList<WidgetsListItem>) {
         activity?.runOnUiThread {
+            val currAdapter = widgets_list.adapter
+            if (currAdapter == null) {
                 WidgetsAdapter(activity!!, widgetsListItems, this).apply {
                     widgets_list.adapter = this
                 }
+            } else {
+                (currAdapter as WidgetsAdapter).updateItems(widgetsListItems)
+            }
         }
     }
 
@@ -215,8 +220,7 @@ class WidgetsFragment(context: Context, attributeSet: AttributeSet) : MyFragment
     }
 
     override fun onWidgetLongPressed(appWidget: AppWidget) {
-        val gridItem =
-            HomeScreenGridItem(
+        val gridItem = HomeScreenGridItem(
             null,
             -1,
             -1,
@@ -229,6 +233,7 @@ class WidgetsFragment(context: Context, attributeSet: AttributeSet) : MyFragment
             ITEM_TYPE_WIDGET,
             appWidget.widgetPreviewImage
         )
+
         activity?.widgetLongPressedOnList(gridItem)
         ignoreTouches = true
     }

app/src/main/kotlin/com/simplemobiletools/launcher/models/AppLauncher.kt

@@ -31,7 +31,7 @@ data class AppLauncher(
 
     fun getHashToCompare() = getStringToCompare().hashCode()
 
-    fun getStringToCompare(): String {
+    private fun getStringToCompare(): String {
         return copy(id = null, drawable = null).toString()
     }
 

app/src/main/kotlin/com/simplemobiletools/launcher/models/AppWidget.kt

@@ -5,10 +5,16 @@ import android.graphics.drawable.Drawable
 data class AppWidget(
     var appPackageName: String,
     var appTitle: String,
-    val appIcon: Drawable,
+    val appIcon: Drawable?,
     val widgetTitle: String,
     val widgetPreviewImage: Drawable?,
     var widthCells: Int,
     val heightCells: Int,
     val isShortcut: Boolean
-) : WidgetsListItem()
+) : WidgetsListItem() {
+    override fun getHashToCompare() = getStringToCompare().hashCode()
+
+    private fun getStringToCompare(): String {
+        return copy(appIcon = null, widgetPreviewImage = null).toString()
+    }
+}

app/src/main/kotlin/com/simplemobiletools/launcher/models/WidgetsListItem.kt

@@ -1,3 +1,5 @@
 package com.simplemobiletools.launcher.models
 
-open class WidgetsListItem
+abstract class WidgetsListItem {
+    abstract fun getHashToCompare(): Int
+}

app/src/main/kotlin/com/simplemobiletools/launcher/models/WidgetsListItemsHolder.kt

@@ -1,3 +1,5 @@
 package com.simplemobiletools.launcher.models
 
-data class WidgetsListItemsHolder(val widgets: ArrayList<AppWidget>) : WidgetsListItem()
+open class WidgetsListItemsHolder(val widgets: ArrayList<AppWidget>) : WidgetsListItem() {
+    override fun getHashToCompare() = widgets.sumOf { it.getHashToCompare() }
+}

app/src/main/kotlin/com/simplemobiletools/launcher/models/WidgetsListSection.kt

@@ -2,4 +2,10 @@ package com.simplemobiletools.launcher.models
 
 import android.graphics.drawable.Drawable
 
-data class WidgetsListSection(var appTitle: String, var appIcon: Drawable) : WidgetsListItem()
+data class WidgetsListSection(var appTitle: String, var appIcon: Drawable?) : WidgetsListItem() {
+    override fun getHashToCompare() = getStringToCompare().hashCode()
+
+    private fun getStringToCompare(): String {
+        return copy(appIcon = null).toString()
+    }
+}