Fixed NPE in IconDialog when icon has no category

Author: maltaisn

lib/src/main/kotlin/com/maltaisn/icondialog/IconDialogPresenter.kt

@@ -17,6 +17,7 @@
 package com.maltaisn.icondialog
 
 import android.os.Bundle
+import androidx.recyclerview.widget.RecyclerView
 import com.maltaisn.icondialog.IconDialog.*
 import com.maltaisn.icondialog.IconDialogContract.View
 import com.maltaisn.icondialog.data.Category
@@ -231,7 +232,7 @@ internal class IconDialogPresenter : IconDialogContract.Presenter {
             }
             i--
         }
-        return -1
+        return RecyclerView.NO_POSITION
     }
 
     override fun onIconItemClicked(pos: Int) {
@@ -349,7 +350,7 @@ internal class IconDialogPresenter : IconDialogContract.Presenter {
             while (i < listItems.size) {
                 val prevId = (listItems.getOrNull(i - 1) as IconItem?)?.icon?.categoryId
                 val currId = (listItems[i] as IconItem).icon.categoryId
-                if (currId != prevId) {
+                if (currId != prevId && currId != Icon.NO_CATEGORY) {
                     listItems.add(i, HeaderItem(iconPack.getCategory(currId)!!))
                     i++
                 }

lib/src/main/kotlin/com/maltaisn/icondialog/StickyHeaderDecoration.kt

@@ -50,7 +50,7 @@ internal class StickyHeaderDecoration(
         val topChildPosition = parent.getChildAdapterPosition(topChild)
         if (topChildPosition == RecyclerView.NO_POSITION) return  // Again, empty list.
 
-        val viewHolder = setHeaderViewHolder(topChildPosition, parent)
+        val viewHolder = setHeaderViewHolder(topChildPosition, parent) ?: return
         val childInContact = getChildInContact(parent, viewHolder.itemView)
         if (childInContact != null) {
             val childInContactPos = parent.getChildAdapterPosition(childInContact)
@@ -84,7 +84,7 @@ internal class StickyHeaderDecoration(
 
     override fun onRequestDisallowInterceptTouchEvent(disallowIntercept: Boolean) = Unit
 
-    private fun setHeaderViewHolder(position: Int, parent: RecyclerView): RecyclerView.ViewHolder {
+    private fun setHeaderViewHolder(position: Int, parent: RecyclerView): RecyclerView.ViewHolder? {
         var viewHolder = headerViewHolder
         if (viewHolder == null) {
             // Header view holder was not yet created
@@ -94,6 +94,10 @@ internal class StickyHeaderDecoration(
 
         // Bind sticky header view holder data
         val headerPos = callback.getHeaderPositionForItem(position)
+        if (headerPos == RecyclerView.NO_POSITION) {
+            return null
+        }
+
         callback.onBindViewHolder(viewHolder, headerPos)
         if (stickyHeaderHeight == -1) {
             // Measure parent RecyclerView

lib/src/main/kotlin/com/maltaisn/icondialog/data/Icon.kt

@@ -17,12 +17,13 @@
 package com.maltaisn.icondialog.data
 
 import android.graphics.drawable.Drawable
+import com.maltaisn.icondialog.data.Icon.Companion.NO_CATEGORY
 import com.maltaisn.icondialog.pack.IconDrawableLoader
 
 
 /**
  * An icon with an unique [id], a [categoryId], a list of [tags] names and SVG [pathData].
- * [categoryId] can be `-1` if the icon has no category.
+ * [categoryId] can be [NO_CATEGORY] if the icon has no category.
  * Icon also have a [width] and a [height] in pixels.
  */
 data class Icon(val id: Int,
@@ -45,4 +46,9 @@ data class Icon(val id: Int,
         internal set
         get() = field?.constantState?.newDrawable()
 
+
+    companion object {
+        const val NO_CATEGORY = -1
+    }
+
 }

lib/src/main/kotlin/com/maltaisn/icondialog/filter/IconFilter.kt

@@ -33,7 +33,7 @@ interface IconFilter : Comparator<Icon>, Parcelable {
     fun queryIcons(pack: IconPack, query: String? = null): MutableList<Icon>
 
     /**
-     * Compare [icon1] and [icon2], two icons which are of the same category.
+     * Compare [icon1] and [icon2], two icons in the same category.
      */
     override fun compare(icon1: Icon, icon2: Icon): Int
 

lib/src/main/kotlin/com/maltaisn/icondialog/pack/IconPackLoader.kt

@@ -84,7 +84,7 @@ class IconPackLoader(context: Context) {
     private fun loadIcons(pack: IconPack, @XmlRes iconsXml: Int) {
         val newIcons = mutableMapOf<Int, Icon>()
         val newCategories = mutableMapOf<Int, Category>()
-        var categoryId: Int = -1
+        var categoryId = Icon.NO_CATEGORY
 
         var documentStarted = false
         var iconStarted = false
@@ -108,7 +108,7 @@ class IconPackLoader(context: Context) {
 
                     when (element) {
                         XML_TAG_CATEGORY -> {
-                            if (categoryId != -1) parseError("Nested category element is not allowed.")
+                            if (categoryId != Icon.NO_CATEGORY) parseError("Nested category element is not allowed.")
                             val category = parseCategory(parser, pack)
                             categoryId = category.id
                             if (categoryId in newCategories) {
@@ -130,7 +130,7 @@ class IconPackLoader(context: Context) {
 
             } else if (eventType == XmlPullParser.END_TAG) {
                 if (element == XML_TAG_CATEGORY) {
-                    categoryId = -1
+                    categoryId = Icon.NO_CATEGORY
                 } else if (element == XML_TAG_ICON) {
                     iconStarted = false
                 }