Fix invalid view holder adapter position exception (#11)

* Fix item delete crash --------- Co-authored-by: Jimmy S <[email protected]>
canopas · Feb 20, 2024 · 801f238 · 801f238
1 parent d62c935
commit 801f238
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Showing 3 changed files with 41 additions and 24 deletions.
diff --git a/compose-recyclerview/src/main/java/com/example/compose_recyclerview/ComposeRecyclerView.kt b/compose-recyclerview/src/main/java/com/example/compose_recyclerview/ComposeRecyclerView.kt
@@ -29,7 +29,7 @@ import com.example.compose_recyclerview.utils.ItemTouchHelperConfig
  * Composable function to display a RecyclerView with dynamically generated Compose items.
  *
  * @param modifier The modifier to be applied to the RecyclerView.
- * @param itemCount The total number of items to be displayed in the RecyclerView.
+ * @param items The list of items to be displayed in the RecyclerView.
  * @param itemBuilder The lambda function responsible for creating the Compose content for each item at the specified index.
  * @param onScrollEnd Callback triggered when the user reaches the end of the list during scrolling.
  * @param orientation The layout direction of the RecyclerView.
@@ -43,10 +43,10 @@ import com.example.compose_recyclerview.utils.ItemTouchHelperConfig
  * @param onCreate Callback to customize the RecyclerView after its creation.
  */
 @Composable
-fun ComposeRecyclerView(
+fun <T> ComposeRecyclerView(
     modifier: Modifier = Modifier,
-    itemCount: Int,
-    itemBuilder: @Composable (index: Int) -> Unit,
+    items: List<T>,
+    itemBuilder: @Composable (item: T, index: Int) -> Unit,
     onScrollEnd: () -> Unit = {},
     orientation: LayoutOrientation = LayoutOrientation.Vertical,
     itemTypeBuilder: ComposeRecyclerViewAdapter.ItemTypeBuilder? = null,
@@ -69,13 +69,14 @@ fun ComposeRecyclerView(
     }
 
     val adapter = remember {
-        ComposeRecyclerViewAdapter().apply {
-            this.totalItems = itemCount
+        ComposeRecyclerViewAdapter<T>().apply {
+            this.itemList = items
             this.itemBuilder = itemBuilder
             itemTypeBuilder?.let {
                 this.itemTypeBuilder = itemTypeBuilder
             }
             this.layoutOrientation = orientation
+            this.layoutManager = layoutManager
         }
     }
 
@@ -119,7 +120,7 @@ fun ComposeRecyclerView(
                             target.bindingAdapterPosition,
                             fromType
                         )
-                        (recyclerView.adapter as ComposeRecyclerViewAdapter).onItemMove(
+                        (recyclerView.adapter as ComposeRecyclerViewAdapter<*>).onItemMove(
                             viewHolder.bindingAdapterPosition,
                             target.bindingAdapterPosition
                         )
@@ -183,7 +184,7 @@ fun ComposeRecyclerView(
         },
         modifier = modifier,
         update = {
-            adapter.update(itemCount, itemBuilder, orientation, itemTypeBuilder)
+            adapter.update(items, itemBuilder, orientation, itemTypeBuilder)
         }
     )
 

diff --git a/...view/src/main/java/com/example/compose_recyclerview/adapter/ComposeRecyclerViewAdapter.kt b/...view/src/main/java/com/example/compose_recyclerview/adapter/ComposeRecyclerViewAdapter.kt
@@ -3,31 +3,30 @@ package com.example.compose_recyclerview.adapter
 import android.view.ViewGroup
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.platform.ComposeView
+import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.example.compose_recyclerview.data.LayoutOrientation
+import kotlin.math.max
 
 /**
  * RecyclerView adapter for handling dynamically generated Compose items.
  */
-class ComposeRecyclerViewAdapter :
-    RecyclerView.Adapter<ComposeRecyclerViewAdapter.ComposeRecyclerViewHolder>(){
+class ComposeRecyclerViewAdapter<T> :
+    RecyclerView.Adapter<ComposeRecyclerViewAdapter<T>.ComposeRecyclerViewHolder>() {
 
     interface ItemTypeBuilder {
         fun getItemType(position: Int): Int
     }
 
-    var totalItems: Int = 0
+    var itemList: List<T> = mutableListOf()
         set(value) {
             if (field == value) return
+            val old = field
             field = value
-            if (field == -1) {
-                notifyItemInserted(0)
-            } else {
-                notifyItemChanged(0)
-            }
+            notifyItemRangeChange(old)
         }
 
-    var itemBuilder: (@Composable (index: Int) -> Unit)? =
+    var itemBuilder: (@Composable (item: T, index: Int) -> Unit)? =
         null
 
     var itemTypeBuilder: ItemTypeBuilder? = null
@@ -39,6 +38,8 @@ class ComposeRecyclerViewAdapter :
             notifyItemChanged(0)
         }
 
+    var layoutManager: LinearLayoutManager? = null
+
     inner class ComposeRecyclerViewHolder(val composeView: ComposeView) :
         RecyclerView.ViewHolder(composeView)
 
@@ -52,12 +53,14 @@ class ComposeRecyclerViewAdapter :
         holder.composeView.apply {
             tag = holder
             setContent {
-                itemBuilder?.invoke(position)
+                if (position < itemList.size) {
+                    itemBuilder?.invoke(itemList[position], position)
+                }
             }
         }
     }
 
-    override fun getItemCount(): Int = totalItems
+    override fun getItemCount(): Int = itemList.size
 
     override fun getItemViewType(position: Int): Int {
         return itemTypeBuilder?.getItemType(position) ?: 0
@@ -68,16 +71,29 @@ class ComposeRecyclerViewAdapter :
     }
 
     fun update(
-        itemCount: Int,
-        itemBuilder: @Composable (index: Int) -> Unit,
+        items: List<T>,
+        itemBuilder: @Composable (item: T, index: Int) -> Unit,
         layoutOrientation: LayoutOrientation,
         itemTypeBuilder: ItemTypeBuilder?
     ) {
-        this.totalItems = itemCount
+        this.itemList = items
         this.itemBuilder = itemBuilder
         this.layoutOrientation = layoutOrientation
         itemTypeBuilder?.let {
             this.itemTypeBuilder = it
         }
     }
+
+    private fun notifyItemRangeChange(oldItems: List<T>) {
+        val oldSize = oldItems.size
+        val newSize = itemList.size
+        val firstVisibleIndex = layoutManager?.findFirstVisibleItemPosition() ?: 0
+        if (newSize < oldSize) {
+            val position = max(0, firstVisibleIndex)
+            notifyItemRangeRemoved(position, oldSize - newSize)
+        } else if (newSize > oldSize) {
+            val start = max(0, firstVisibleIndex)
+            notifyItemRangeInserted(start, newSize - oldSize)
+        }
+    }
 }
diff --git a/sample-app/src/main/java/com/example/composerecyclerview/MainActivity.kt b/sample-app/src/main/java/com/example/composerecyclerview/MainActivity.kt
@@ -62,8 +62,8 @@ class MainActivity : ComponentActivity() {
 
                     ComposeRecyclerView(
                         modifier = Modifier.fillMaxSize(),
-                        itemCount = 1 + userDataList.size + 1 + otherUsersDataList.size,
-                        itemBuilder = { index ->
+                        items = listOf(1) + userDataList + listOf(1) + otherUsersDataList,
+                        itemBuilder = { item, index ->
                             if (index == 0) {
                                 Box(
                                     modifier = Modifier.fillMaxWidth(),