Fix focus searches not checking items in order

dpadrecyclerview/src/main/java/com/rubensousa/dpadrecyclerview/layoutmanager/focus/DefaultFocusInterceptor.kt

@@ -38,12 +38,67 @@ internal class DefaultFocusInterceptor(
         position: Int,
         direction: Int
     ): View? {
-        val absoluteDirection = FocusDirection.getAbsoluteDirection(
+        val focusAbsoluteDirection = FocusDirection.getAbsoluteDirection(
             direction = direction,
             isVertical = configuration.isVertical(),
             reverseLayout = layoutInfo.shouldReverseLayout()
         )
-        return focusFinder.findNextFocus(recyclerView, focusedView, absoluteDirection)
+        // Exit early if the focus finder can't find focus already
+        val nextFocusFinderView = focusFinder.findNextFocus(
+            recyclerView, focusedView, focusAbsoluteDirection
+        ) ?: return null
+        val currentViewHolder = layoutInfo.getChildViewHolder(focusedView)
+        val nextViewHolder = layoutInfo.getChildViewHolder(nextFocusFinderView)
+        /**
+         * Check if the focus finder has found another focusable view for the same ViewHolder
+         * This might happen when sub positions are used
+         */
+        if (nextViewHolder === currentViewHolder && nextFocusFinderView !== focusedView) {
+            return nextFocusFinderView
+        }
+        return if (configuration.spanCount == 1) {
+            val relativeFocusDirection = FocusDirection.from(
+                direction, isVertical = configuration.isVertical(),
+                reverseLayout = configuration.reverseLayout
+            ) ?: return nextFocusFinderView
+            findNextLinearChild(position, relativeFocusDirection)
+        } else {
+            return nextFocusFinderView
+        }
     }
 
+    private fun findNextLinearChild(position: Int, direction: FocusDirection): View? {
+        // We only support the main direction
+        if (direction.isSecondary()) {
+            return null
+        }
+        val positionIncrement = layoutInfo.getPositionIncrement(
+            goingForward = direction == FocusDirection.NEXT_ROW
+                    || direction == FocusDirection.NEXT_COLUMN
+        )
+        val nextPosition = position + positionIncrement
+        // Jump early if we're going out of bounds
+        if (nextPosition < 0 || nextPosition == layoutInfo.getItemCount()) {
+            return null
+        }
+        return findNextFocusableView(
+            fromPosition = nextPosition,
+            positionIncrement = positionIncrement
+        )
+    }
+
+    private fun findNextFocusableView(
+        fromPosition: Int,
+        positionIncrement: Int
+    ): View? {
+        var currentPosition = fromPosition
+        while (currentPosition >= 0 && currentPosition < layoutInfo.getItemCount()) {
+            val view = layoutInfo.findViewByPosition(currentPosition)
+            if (view != null && layoutInfo.isViewFocusable(view)) {
+                return view
+            }
+            currentPosition += positionIncrement
+        }
+        return null
+    }
 }

sample/src/main/java/com/rubensousa/dpadrecyclerview/sample/ui/screen/dynamic/MediumListDelegate.kt

@@ -19,7 +19,7 @@ package com.rubensousa.dpadrecyclerview.sample.ui.screen.dynamic
 import android.view.LayoutInflater
 import android.view.ViewGroup
 import com.rubensousa.dpadrecyclerview.UnboundViewPool
-import com.rubensousa.dpadrecyclerview.sample.databinding.AdapterListComposeBinding
+import com.rubensousa.dpadrecyclerview.sample.databinding.AdapterListMediumBinding
 import com.rubensousa.dpadrecyclerview.sample.ui.model.RecyclerViewItem
 import com.rubensousa.dpadrecyclerview.sample.ui.model.ViewHolderDelegate
 import com.rubensousa.dpadrecyclerview.state.DpadScrollState
@@ -32,7 +32,7 @@ class MediumListDelegate(
     override fun onCreateViewHolder(parent: ViewGroup): MediumListViewHolder {
         return MediumListViewHolder(
             viewPool,
-            AdapterListComposeBinding.inflate(
+            AdapterListMediumBinding.inflate(
                 LayoutInflater.from(parent.context), parent, false
             )
         )

sample/src/main/java/com/rubensousa/dpadrecyclerview/sample/ui/screen/dynamic/MediumListViewHolder.kt

@@ -18,13 +18,13 @@ package com.rubensousa.dpadrecyclerview.sample.ui.screen.dynamic
 
 import com.rubensousa.dpadrecyclerview.DpadViewHolder
 import com.rubensousa.dpadrecyclerview.UnboundViewPool
-import com.rubensousa.dpadrecyclerview.sample.databinding.AdapterListComposeBinding
+import com.rubensousa.dpadrecyclerview.sample.databinding.AdapterListMediumBinding
 import com.rubensousa.dpadrecyclerview.sample.ui.model.DelegateViewHolder
 import com.rubensousa.dpadrecyclerview.sample.ui.widgets.common.ListAnimator
 
 class MediumListViewHolder(
     private val recycledViewPool: UnboundViewPool,
-    private val binding: AdapterListComposeBinding,
+    private val binding: AdapterListMediumBinding,
 ) : DelegateViewHolder<MediumList>(binding.root), DpadViewHolder {
 
     val recyclerView = binding.cardRecyclerView

sample/src/main/res/layout/adapter_list_medium.xml

@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/cardListLayout"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:clipChildren="false"
+    android:orientation="vertical">
+
+    <TextView
+        android:id="@+id/cardListTextView"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="@dimen/list_margin_start"
+        android:textColor="@color/white"
+        tools:text="Headline" />
+
+    <com.rubensousa.dpadrecyclerview.DpadRecyclerView
+        android:id="@+id/cardRecyclerView"
+        android:layout_width="match_parent"
+        android:layout_height="220dp"
+        android:clipChildren="false"
+        android:gravity="center"
+        android:nextFocusDown="@id/mediumButtonAnchor"
+        android:orientation="horizontal"
+        app:dpadRecyclerViewChildAlignmentFraction="0.0"
+        app:dpadRecyclerViewItemEdgeSpacing="@dimen/list_margin_start"
+        app:dpadRecyclerViewItemSpacing="@dimen/horizontal_item_spacing"
+        app:dpadRecyclerViewParentAlignmentFraction="0.0"
+        app:dpadRecyclerViewParentAlignmentOffset="@dimen/list_margin_start" />
+
+    <FrameLayout
+        android:id="@+id/mediumButtonAnchor"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:visibility="gone"
+        android:layout_marginStart="@dimen/list_margin_start"
+        android:background="@color/list_item_background"
+        android:focusable="true"
+        android:focusableInTouchMode="true">
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:duplicateParentState="true"
+            android:padding="8dp"
+            android:text="Sub position"
+            android:textColor="@color/list_item_text" />
+
+    </FrameLayout>
+
+</LinearLayout>