Draw home screen grid over widgets

This closes #131

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

@@ -920,6 +920,7 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
         post {
             setWillNotDraw(false)
             invalidate()
+            binding.drawingArea.invalidate()
         }
     }
 
@@ -927,9 +928,7 @@ class HomeScreenGrid(context: Context, attrs: AttributeSet, defStyle: Int) : Rel
 
     private fun getFakeHeight() = height - sideMargins.top - sideMargins.bottom
 
-    @SuppressLint("DrawAllocation")
-    override fun onDraw(canvas: Canvas) {
-        super.onDraw(canvas)
+    fun drawInto(canvas: Canvas) {
         if (cells.isEmpty()) {
             fillCellSizes()
         }

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

@@ -0,0 +1,16 @@
+package com.simplemobiletools.launcher.views
+
+import android.content.Context
+import android.graphics.Canvas
+import android.util.AttributeSet
+import android.view.View
+
+class HomeScreenGridDrawingArea @JvmOverloads constructor(
+    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
+) : View(context, attrs, defStyleAttr) {
+
+    override fun onDraw(canvas: Canvas) {
+        super.onDraw(canvas)
+        (parent as HomeScreenGrid).drawInto(canvas)
+    }
+}

app/src/main/res/layout/home_screen_grid.xml

@@ -4,6 +4,13 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
+    <!-- Drawing area with Z translation so it is drawn over widgets -->
+    <com.simplemobiletools.launcher.views.HomeScreenGridDrawingArea
+        android:id="@+id/drawing_area"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:translationZ="1dp"/>
+
     <com.simplemobiletools.launcher.views.MyAppWidgetResizeFrame
         android:id="@+id/resize_frame"
         android:layout_width="match_parent"