Fix focus search for reverse grids

dpadrecyclerview/src/androidTest/kotlin/com/rubensousa/dpadrecyclerview/test/tests/focus/ReverseGridFocusTest.kt

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2022 Rúben Sousa
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.rubensousa.dpadrecyclerview.test.tests.focus
+
+import androidx.recyclerview.widget.RecyclerView
+import com.rubensousa.dpadrecyclerview.ChildAlignment
+import com.rubensousa.dpadrecyclerview.ParentAlignment
+import com.rubensousa.dpadrecyclerview.test.TestLayoutConfiguration
+import com.rubensousa.dpadrecyclerview.test.helpers.assertFocusAndSelection
+import com.rubensousa.dpadrecyclerview.test.tests.DpadRecyclerViewTest
+import com.rubensousa.dpadrecyclerview.testing.KeyEvents
+import com.rubensousa.dpadrecyclerview.testing.rules.DisableIdleTimeoutRule
+import org.junit.Rule
+import org.junit.Test
+
+class ReverseGridFocusTest : DpadRecyclerViewTest() {
+
+    @get:Rule
+    val idleTimeoutRule = DisableIdleTimeoutRule()
+
+    private val spanCount = 5
+
+    override fun getDefaultLayoutConfiguration(): TestLayoutConfiguration {
+        return TestLayoutConfiguration(
+            spans = spanCount,
+            orientation = RecyclerView.VERTICAL,
+            parentAlignment = ParentAlignment(
+                edge = ParentAlignment.Edge.MIN_MAX
+            ),
+            reverseLayout = true,
+            childAlignment = ChildAlignment(offset = 0)
+        )
+    }
+
+    @Test
+    fun testFocusStartOfRow() {
+        // given
+        launchFragment()
+
+        // when
+        KeyEvents.pressLeft(times = spanCount)
+
+        // then
+        assertFocusAndSelection(spanCount - 1)
+    }
+
+}

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

@@ -122,7 +122,11 @@ internal class FocusDispatcher(
         }
     }
 
-    fun onInterceptFocusSearch(recyclerView: DpadRecyclerView?, focused: View, direction: Int): View? {
+    fun onInterceptFocusSearch(
+        recyclerView: DpadRecyclerView?,
+        focused: View,
+        direction: Int
+    ): View? {
         val currentRecyclerView = recyclerView ?: return focused
 
         if (!isFocusSearchEnabled(currentRecyclerView)) {
@@ -434,7 +438,11 @@ internal class FocusDispatcher(
         if (movement == FocusDirection.NEXT_COLUMN || movement == FocusDirection.PREVIOUS_COLUMN) {
             return focusNextSpanColumn(
                 focusedPosition = focusedPosition,
-                next = movement == FocusDirection.NEXT_COLUMN,
+                next = if (!layoutInfo.shouldReverseLayout()) {
+                    movement == FocusDirection.NEXT_COLUMN
+                } else {
+                    movement == FocusDirection.PREVIOUS_COLUMN
+                },
                 views = views,
                 direction = direction,
                 focusableMode = focusableMode
@@ -477,11 +485,7 @@ internal class FocusDispatcher(
         direction: Int,
         focusableMode: Int
     ): Boolean {
-        val positionIncrement = if (next xor layoutInfo.shouldReverseLayout()) {
-            1
-        } else {
-            -1
-        }
+        val positionIncrement = layoutInfo.getPositionIncrement(next)
         val nextPosition = focusedPosition + positionIncrement
         if (nextPosition < 0 || nextPosition >= layout.itemCount) {
             return false