Handle moving items inside a folder

app/src/main/kotlin/com/simplemobiletools/launcher/interfaces/HomeScreenGridItemsDao.kt

@@ -44,8 +44,8 @@ interface HomeScreenGridItemsDao {
     @Query("DELETE FROM home_screen_grid_items WHERE parent_id IN (SELECT id FROM home_screen_grid_items WHERE package_name = :packageName)")
     fun deleteItemsByParentPackageName(packageName: String)
 
-    @Query("UPDATE home_screen_grid_items SET `left` = `left` + :shiftBy WHERE parent_id == :folderId AND `left` >= :shiftFrom")
+    @Query("UPDATE home_screen_grid_items SET `left` = `left` + :shiftBy WHERE parent_id == :folderId AND `left` > :shiftFrom AND id != :excludingId")
-    fun shiftFolderItems(folderId: Long, shiftFrom: Int, shiftBy: Int)
+    fun shiftFolderItems(folderId: Long, shiftFrom: Int, shiftBy: Int, excludingId: Long)
 
     @Transaction
     fun deleteByPackageName(packageName: String) {

app/src/main/kotlin/com/simplemobiletools/launcher/views/HomeScreenGrid.kt

@@ -250,6 +250,11 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
 
     fun itemDraggingStarted(draggedGridItem: HomeScreenGridItem) {
         draggedItem = draggedGridItem
+
+        if (draggedGridItem.type == ITEM_TYPE_WIDGET) {
+            closeFolder()
+        }
+
         if (draggedItem!!.drawable == null) {
             if (draggedItem?.type == ITEM_TYPE_FOLDER) {
                 draggedItem!!.drawable =
@@ -424,6 +429,10 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
             // check if the destination cell is empty
             var isDroppingPositionValid = true
             val wantedCell = Pair(xIndex, yIndex)
+            // No moving folder into the dock
+            if (draggedHomeGridItem?.type == ITEM_TYPE_FOLDER && yIndex == rowCount - 1) {
+                isDroppingPositionValid = false
+            } else {
                 gridItems.filterVisibleOnly().forEach { item ->
                     for (xCell in item.left..item.right) {
                         for (yCell in item.getDockAdjustedTop(rowCount)..item.getDockAdjustedBottom(rowCount)) {
@@ -436,6 +445,7 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
                         }
                     }
                 }
+            }
 
             if (isDroppingPositionValid) {
                 draggedHomeGridItem?.apply {
@@ -462,19 +472,38 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
     }
 
     private fun addAppIconOrShortcut() {
+        var isDroppingPositionValid: Boolean = false
+        var potentialParent: HomeScreenGridItem? = null
+        var xIndex: Int? = null
+        var yIndex: Int? = null
+        var redrawIcons = false
+
+        val folder = currentlyOpenFolder
+        if (folder != null && folder.getFolderItemsRect().contains(
+                (sideMargins.left + draggedItemCurrentCoords.first).toFloat(),
+                (sideMargins.top + draggedItemCurrentCoords.second).toFloat()
+            )
+        ) {
+            val center = folder.getFolderGridCenters().minBy {
+                abs(it.second - draggedItemCurrentCoords.first + sideMargins.left) + abs(it.third - draggedItemCurrentCoords.second + sideMargins.top)
+            }
+            isDroppingPositionValid = true
+            potentialParent = folder
+            xIndex = center.first
+            yIndex = 0
+            redrawIcons = true
+        } else {
             val center = gridCenters.minBy {
                 Math.abs(it.first - draggedItemCurrentCoords.first + sideMargins.left) + Math.abs(it.second - draggedItemCurrentCoords.second + sideMargins.top)
             }
 
-        var redrawIcons = false
             val gridCells = getClosestGridCells(center)
             if (gridCells != null) {
-            val xIndex = gridCells.first
+                xIndex = gridCells.first
-            val yIndex = gridCells.second
+                yIndex = gridCells.second
 
                 // check if the destination cell is empty or a folder
-            var isDroppingPositionValid = true
+                isDroppingPositionValid = true
-            var potentialParent: HomeScreenGridItem? = null
                 val wantedCell = Pair(xIndex, yIndex)
                 gridItems.filterVisibleOnly().forEach { item ->
                     for (xCell in item.left..item.right) {
@@ -482,7 +511,7 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
                             val cell = Pair(xCell, yCell)
                             val isAnyCellOccupied = wantedCell == cell
                             if (isAnyCellOccupied) {
-                            if (item.type != ITEM_TYPE_WIDGET) {
+                                if (item.type != ITEM_TYPE_WIDGET && !item.docked) {
                                     potentialParent = item
                                 } else {
                                     isDroppingPositionValid = false
@@ -492,13 +521,15 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
                         }
                     }
                 }
+            }
+        }
 
         if (isDroppingPositionValid) {
             val draggedHomeGridItem = gridItems.firstOrNull { it.id == draggedItem?.id }
 
             if (potentialParent != null) {
                 if (potentialParent?.type == ITEM_TYPE_FOLDER) {
-                        addAppIconOrShortcut(draggedHomeGridItem, xIndex, yIndex, potentialParent?.id)
+                    addAppIconOrShortcut(draggedHomeGridItem, xIndex!!, yIndex!!, potentialParent?.id, toFolderEnd = potentialParent != currentlyOpenFolder)
                 } else {
                     val parentItem = potentialParent!!.copy(
                         type = ITEM_TYPE_FOLDER,
@@ -515,20 +546,19 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
                         }
                         (context as? MainActivity)?.runOnUiThread {
                             gridItems.add(parentItem)
-                                addAppIconOrShortcut(draggedHomeGridItem, xIndex, yIndex, newId)
+                            addAppIconOrShortcut(draggedHomeGridItem, xIndex!!, yIndex!!, newId)
                         }
                     }
                 }
                 return
             } else {
-                    addAppIconOrShortcut(draggedHomeGridItem, xIndex, yIndex)
+                addAppIconOrShortcut(draggedHomeGridItem, xIndex!!, yIndex!!)
                 return
             }
         } else {
             performHapticFeedback()
             redrawIcons = true
         }
-        }
 
         draggedItem = null
         draggedItemCurrentCoords = Pair(-1, -1)
@@ -537,12 +567,24 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
         }
     }
 
-    private fun addAppIconOrShortcut(draggedHomeGridItem: HomeScreenGridItem?, xIndex: Int, yIndex: Int, newParentId: Long? = null) {
+    private fun addAppIconOrShortcut(
+        draggedHomeGridItem: HomeScreenGridItem?,
+        xIndex: Int,
+        yIndex: Int,
+        newParentId: Long? = null,
+        toFolderEnd: Boolean = true
+    ) {
         val finalXIndex = if (newParentId != null) {
-            if (newParentId == draggedHomeGridItem?.parentId) {
+            if (toFolderEnd) {
-                draggedHomeGridItem.left
-            } else {
                 gridItems.firstOrNull { it.id == newParentId }?.getFolderItems()?.maxOf { it.left + 1 } ?: 0
+            } else {
+                min(xIndex, gridItems.firstOrNull { it.id == newParentId }?.getFolderItems()?.maxOf {
+                    if (draggedHomeGridItem?.parentId == newParentId) {
+                        it.left
+                    } else {
+                        it.left + 1
+                    }
+                } ?: 0)
             }
         } else {
             xIndex
@@ -572,11 +614,19 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
                     context.homeScreenGridItemsDB.updateItemPosition(left, top, right, bottom, page, docked, newParentId, id!!)
                     if (deleteOldParent && oldParentId != null) {
                         context.homeScreenGridItemsDB.deleteById(oldParentId)
-                    } else if (oldParentId != null) {
+                    } else if (oldParentId != null && gridItems.none { it.parentId == oldParentId && it.left == oldLeft }) {
-                        gridItems.filter { it.parentId == oldParentId && it.left >= oldLeft }.forEach {
+                        gridItems.filter { it.parentId == oldParentId && it.left > oldLeft && it.id != id }.forEach {
                             it.left -= 1
                         }
-                        context.homeScreenGridItemsDB.shiftFolderItems(oldParentId, oldLeft, -1)
+                        context.homeScreenGridItemsDB.shiftFolderItems(oldParentId, oldLeft, -1, id!!)
+                    }
+
+                    if (newParentId != null && gridItems.any { it.parentId == newParentId && it.left == left }) {
+                        gridItems.filter { it.parentId == newParentId && it.left >= left && it.id != id }.forEach {
+                            it.left += 1
+                        }
+
+                        context.homeScreenGridItemsDB.shiftFolderItems(newParentId, left - 1, +1, id!!)
                     }
                 }
             }
@@ -1024,6 +1074,21 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
 
         if (draggedItem != null && draggedItemCurrentCoords.first != -1 && draggedItemCurrentCoords.second != -1) {
             if (draggedItem!!.type == ITEM_TYPE_ICON || draggedItem!!.type == ITEM_TYPE_SHORTCUT || draggedItem!!.type == ITEM_TYPE_FOLDER) {
+                if (folder != null && folder.getFolderItemsRect().contains(
+                        (sideMargins.left + draggedItemCurrentCoords.first).toFloat(),
+                        (sideMargins.top + draggedItemCurrentCoords.second).toFloat()
+                    )
+                ) {
+
+                    val center = folder.getFolderGridCenters().minBy {
+                        abs(it.second - draggedItemCurrentCoords.first + sideMargins.left) + abs(it.third - draggedItemCurrentCoords.second + sideMargins.top)
+                    }
+
+                    val shadowX = center.second - cellWidth / 2 + iconMargin + iconSize / 2f + extraXMargin
+                    val shadowY = center.third - cellHeight / 2 + iconMargin + iconSize / 2f + extraYMargin
+
+                    canvas.drawCircle(shadowX, shadowY, iconSize / 2f, dragShadowCirclePaint)
+                } else {
                     // draw a circle under the current cell
                     val center = gridCenters.minBy {
                         abs(it.first - draggedItemCurrentCoords.first + sideMargins.left) + abs(it.second - draggedItemCurrentCoords.second + sideMargins.top)
@@ -1040,6 +1105,7 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
 
                         canvas.drawCircle(shadowX, shadowY, iconSize / 2f, dragShadowCirclePaint)
                     }
+                }
 
                 // show the app icon itself at dragging, move it above the finger a bit to make it visible
                 val drawableX = (draggedItemCurrentCoords.first - iconSize / 1.5f).toInt()
@@ -1415,6 +1481,23 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
         )
     }
 
+    private fun HomeScreenGridItem.getFolderGridCenters(): List<Triple<Int, Int, Int>> {
+        val count = getFolderItems().count()
+        val columnsCount = ceil(sqrt(count.toDouble())).roundToInt()
+        val rowsCount = ceil(count.toFloat() / columnsCount).roundToInt()
+        val folderItemsRect = getFolderItemsRect()
+        return (0 until columnsCount * rowsCount)
+            .toList()
+            .map { Pair(it % columnsCount, it / columnsCount) }
+            .mapIndexed { index, (x, y) ->
+                Triple(
+                    index,
+                    (folderItemsRect.left + x * cellWidth + cellWidth / 2).toInt(),
+                    (folderItemsRect.top + y * cellHeight + cellHeight / 2).toInt()
+                )
+            }
+    }
+
     private fun HomeScreenGridItem.getPositionInFolder(folder: HomeScreenGridItem): Pair<Int, Int> {
         val count = folder.getFolderItems().count()
         val columnsCount = ceil(sqrt(count.toDouble())).roundToInt()