Expose fromUser in drag stop callback

dpadrecyclerview/api/dpadrecyclerview.api

@@ -56,7 +56,7 @@ public abstract interface class com/rubensousa/dpadrecyclerview/DpadDragHelper$D
 
 public abstract interface class com/rubensousa/dpadrecyclerview/DpadDragHelper$DragCallback {
 	public abstract fun onDragStarted (Landroidx/recyclerview/widget/RecyclerView$ViewHolder;)V
-	public abstract fun onDragStopped ()V
+	public abstract fun onDragStopped (Z)V
 }
 
 public final class com/rubensousa/dpadrecyclerview/DpadLoopDirection : java/lang/Enum {

dpadrecyclerview/src/androidTest/kotlin/com/rubensousa/dpadrecyclerview/test/tests/drag/DragHelperGridTest.kt

@@ -42,7 +42,7 @@ class DragHelperGridTest {
     private val numberOfItems = 50
     private val spanCount = 5
     private val dragStarted = mutableListOf<RecyclerView.ViewHolder>()
-    private var dragStopCount = 0
+    private val dragStopRequests = mutableListOf<DragStopRequest>()
 
     @Before
     fun setup() {
@@ -78,8 +78,8 @@ class DragHelperGridTest {
                         dragStarted.add(viewHolder)
                     }
 
-                    override fun onDragStopped() {
-                        dragStopCount++
+                    override fun onDragStopped(fromUser: Boolean) {
+                        dragStopRequests.add(DragStopRequest(fromUser))
                     }
                 }
             )

dpadrecyclerview/src/androidTest/kotlin/com/rubensousa/dpadrecyclerview/test/tests/drag/DragHelperLinearTest.kt

@@ -44,7 +44,7 @@ class DragHelperLinearTest {
     private lateinit var testAdapter: TestAdapter
     private val numberOfItems = 10
     private val dragStarted = mutableListOf<RecyclerView.ViewHolder>()
-    private var dragStopCount = 0
+    private val dragStopRequests = mutableListOf<DragStopRequest>()
 
     @Before
     fun setup() {
@@ -80,8 +80,8 @@ class DragHelperLinearTest {
                         dragStarted.add(viewHolder)
                     }
 
-                    override fun onDragStopped() {
-                        dragStopCount++
+                    override fun onDragStopped(fromUser: Boolean) {
+                        dragStopRequests.add(DragStopRequest(fromUser))
                     }
                 }
             )
@@ -100,7 +100,8 @@ class DragHelperLinearTest {
         }
 
         // then
-        assertThat(dragStopCount).isEqualTo(1)
+        assertThat(dragStopRequests).hasSize(1)
+        assertThat(dragStopRequests.first().fromUser).isFalse()
     }
 
     @Test
@@ -131,12 +132,11 @@ class DragHelperLinearTest {
     }
 
     @Test
-    fun testDragIsCanceledOnCertainKeyEvents() {
+    fun testDragStopsOnCertainKeyEvents() {
         // given
         val cancelKeyCodes = setOf(
             KeyEvent.KEYCODE_ENTER,
             KeyEvent.KEYCODE_DPAD_CENTER,
-            KeyEvent.KEYCODE_BACK,
         )
 
         // when
@@ -147,7 +147,10 @@ class DragHelperLinearTest {
         }
 
         // then
-        assertThat(dragStopCount).isEqualTo(cancelKeyCodes.size)
+        assertThat(dragStopRequests).hasSize(cancelKeyCodes.size)
+        dragStopRequests.forEach {
+            assertThat(it.fromUser).isTrue()
+        }
     }
 
     @Test

dpadrecyclerview/src/androidTest/kotlin/com/rubensousa/dpadrecyclerview/test/tests/drag/DragStopRequest.kt

@@ -0,0 +1,3 @@
+package com.rubensousa.dpadrecyclerview.test.tests.drag
+
+data class DragStopRequest(val fromUser: Boolean)

dpadrecyclerview/src/main/java/com/rubensousa/dpadrecyclerview/DpadDragHelper.kt

@@ -26,15 +26,18 @@ import java.util.Collections
  *
  * To use this, your adapter needs to implement [DpadDragHelper.DragAdapter]
  * and expose the mutable collection via [DpadDragHelper.DragAdapter.getMutableItems].
+ *
+ * @param adapter the adapter that backs the data that can be arranged
+ * @param callback the callback for notifying dragging state changes
+ * @param stopKeyCodes key codes that will be accepted to stop the dragging state
  */
 class DpadDragHelper<T>(
     private val adapter: DragAdapter<T>,
     private val callback: DragCallback,
-    private val cancelKeyCodes: Set<Int> = setOf(
+    private val stopKeyCodes: Set<Int> = setOf(
         KeyEvent.KEYCODE_DPAD_CENTER,
         KeyEvent.KEYCODE_ENTER,
-        KeyEvent.KEYCODE_BACK
-    )
+    ),
 ) {
 
     /**
@@ -50,8 +53,11 @@ class DpadDragHelper<T>(
             if (!isDragging) {
                 return false
             }
-            if (cancelKeyCodes.contains(event.keyCode)) {
-                stopDrag()
+            if (stopKeyCodes.contains(event.keyCode)) {
+                if (event.action == KeyEvent.ACTION_UP) {
+                    // Only stop dragging after the user releases the key
+                    stopDragging(fromUser = true)
+                }
                 return true
             }
             if (event.action == KeyEvent.ACTION_UP) {
@@ -120,7 +126,7 @@ class DpadDragHelper<T>(
 
     private fun startDrag(
         recyclerView: DpadRecyclerView,
-        viewHolder: RecyclerView.ViewHolder
+        viewHolder: RecyclerView.ViewHolder,
     ) {
         isDragging = true
         previousKeyInterceptListener = recyclerView.getOnKeyInterceptListener()
@@ -136,6 +142,10 @@ class DpadDragHelper<T>(
      * [DragCallback.onDragStopped] will be called after this method
      */
     fun stopDrag() {
+        stopDragging(fromUser = false)
+    }
+
+    private fun stopDragging(fromUser: Boolean) {
         if (!isDragging) {
             return
         }
@@ -145,7 +155,7 @@ class DpadDragHelper<T>(
             }
         }
         isDragging = false
-        callback.onDragStopped()
+        callback.onDragStopped(fromUser)
     }
 
     private fun onKeyEvent(event: KeyEvent): Boolean {
@@ -198,7 +208,7 @@ class DpadDragHelper<T>(
         adapter: RecyclerView.Adapter<*>,
         items: MutableList<T>,
         srcIndex: Int,
-        targetIndex: Int
+        targetIndex: Int,
     ) {
         Collections.swap(items, srcIndex, targetIndex)
         adapter.notifyItemMoved(srcIndex, targetIndex)
@@ -212,7 +222,7 @@ class DpadDragHelper<T>(
         adapter: RecyclerView.Adapter<*>,
         items: MutableList<T>,
         srcIndex: Int,
-        targetIndex: Int
+        targetIndex: Int,
     ) {
         val item = items.removeAt(srcIndex)
         items.add(targetIndex, item)
@@ -247,8 +257,10 @@ class DpadDragHelper<T>(
 
         /**
          * Indicates that the dragging action has stopped
+         * @param fromUser true if this was triggered by the user,
+         * or false if [stopDrag] was called manually by the app
          */
-        fun onDragStopped()
+        fun onDragStopped(fromUser: Boolean)
     }
 
 }

sample/src/main/java/com/rubensousa/dpadrecyclerview/sample/ui/screen/drag/DragAndDropFragment.kt

@@ -18,12 +18,16 @@ package com.rubensousa.dpadrecyclerview.sample.ui.screen.drag
 
 import android.os.Bundle
 import android.view.View
+import androidx.activity.OnBackPressedCallback
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.remember
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.unit.dp
 import androidx.fragment.app.Fragment
+import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.recyclerview.widget.DefaultItemAnimator
 import androidx.recyclerview.widget.RecyclerView
 import com.rubensousa.dpadrecyclerview.DpadDragHelper
@@ -32,6 +36,7 @@ import com.rubensousa.dpadrecyclerview.sample.databinding.ScreenDragDropBinding
 import com.rubensousa.dpadrecyclerview.sample.ui.dpToPx
 import com.rubensousa.dpadrecyclerview.sample.ui.viewBinding
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.launch
 
 class DragAndDropFragment : Fragment(R.layout.screen_drag_drop) {
 
@@ -49,17 +54,36 @@ class DragAndDropFragment : Fragment(R.layout.screen_drag_drop) {
             override fun onDragStarted(viewHolder: RecyclerView.ViewHolder) {
                 dragState.value = dragAdapter.getItem(viewHolder.bindingAdapterPosition)
             }
-            override fun onDragStopped() {
+
+            override fun onDragStopped(fromUser: Boolean) {
+                if (fromUser) {
+                    // User requested dragging to stop
+                } else {
+                    // Dragging was stopped manually
+                }
                 dragState.value = null
             }
         }
     )
+    private val backPressCallback = object : OnBackPressedCallback(false) {
+        override fun handleOnBackPressed() {
+            dragHelper.stopDrag()
+        }
+    }
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
         setupRecyclerView()
         setDragButtonContent()
         dragAdapter.submitList(List(20) { it }.toMutableList())
+        requireActivity().onBackPressedDispatcher.addCallback(viewLifecycleOwner, backPressCallback)
+        viewLifecycleOwner.lifecycleScope.launch {
+            repeatOnLifecycle(Lifecycle.State.STARTED) {
+                dragState.collect { draggingItem ->
+                    backPressCallback.isEnabled = draggingItem != null
+                }
+            }
+        }
     }
 
     private fun setupRecyclerView() {

sample/src/main/java/com/rubensousa/dpadrecyclerview/sample/ui/screen/drag/DragAndDropGridFragment.kt

@@ -31,7 +31,6 @@ import com.rubensousa.dpadrecyclerview.sample.R
 import com.rubensousa.dpadrecyclerview.sample.databinding.ScreenDragDropBinding
 import com.rubensousa.dpadrecyclerview.sample.ui.dpToPx
 import com.rubensousa.dpadrecyclerview.sample.ui.viewBinding
-import com.rubensousa.dpadrecyclerview.spacing.DpadGridSpacingDecoration
 import kotlinx.coroutines.flow.MutableStateFlow
 
 class DragAndDropGridFragment : Fragment(R.layout.screen_drag_drop_grid) {
@@ -51,7 +50,7 @@ class DragAndDropGridFragment : Fragment(R.layout.screen_drag_drop_grid) {
             override fun onDragStarted(viewHolder: RecyclerView.ViewHolder) {
                 dragState.value = dragAdapter.getItem(viewHolder.bindingAdapterPosition)
             }
-            override fun onDragStopped() {
+            override fun onDragStopped(fromUser: Boolean) {
                 dragState.value = null
             }
         }
@@ -72,12 +71,8 @@ class DragAndDropGridFragment : Fragment(R.layout.screen_drag_drop_grid) {
                 // For faster moves
                 moveDuration = 100
             }
-            addItemDecoration(
-                DpadGridSpacingDecoration.create(
-                    itemSpacing = dpToPx(16.dp),
-                    edgeSpacing = dpToPx(48.dp),
-                )
-            )
+            setItemSpacing(dpToPx(16.dp))
+            setItemEdgeSpacing(dpToPx(48.dp))
         }
     }
 

sample/src/main/java/com/rubensousa/dpadrecyclerview/sample/ui/screen/drag/DraggableItem.kt

@@ -62,7 +62,7 @@ fun DraggableItem(
     }
     Box(
         modifier = modifier
-            .size(200.dp)
+            .size(100.dp)
             .then(
                 if (isDragging) {
                     Modifier.border(8.dp, Color.Blue, RoundedCornerShape(8.dp))

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

@@ -26,13 +26,14 @@
         android:clipChildren="false"
         android:gravity="center"
         android:orientation="horizontal"
-        app:dpadRecyclerViewChildAlignmentFraction="0.5"
+        app:dpadRecyclerViewChildAlignmentFraction="0"
         app:dpadRecyclerViewFocusOutBack="false"
         app:dpadRecyclerViewFocusOutFront="false"
         app:dpadRecyclerViewItemEdgeSpacing="@dimen/list_margin_start"
         app:dpadRecyclerViewItemSpacing="@dimen/item_spacing"
         app:dpadRecyclerViewParentAlignmentEdge="min_max"
-        app:dpadRecyclerViewParentAlignmentFraction="0.5" />
+        app:dpadRecyclerViewParentAlignmentFraction="0"
+        app:dpadRecyclerViewParentAlignmentOffset="@dimen/list_margin_start" />
 
 
 </LinearLayout>