Multi-selection: Selection mode

app/src/main/java/com/duckduckgo/app/browser/tabpreview/TabEntityDiffCallback.kt

@@ -20,11 +20,18 @@ import android.os.Bundle
 import androidx.recyclerview.widget.DiffUtil
 import com.duckduckgo.app.tabs.model.TabEntity
 
-class TabEntityDiffCallback(old: List<TabEntity>, new: List<TabEntity>) : DiffUtil.Callback() {
+class TabEntityDiffCallback(
+    old: List<TabEntity>,
+    new: List<TabEntity>,
+    oldSelectedIds: List<String>? = null,
+    newSelectedIds: List<String>? = null,
+) : DiffUtil.Callback() {
 
     // keep a local copy of the lists to avoid any changes to the lists during the diffing process
     private val oldList = old.toList()
     private val newList = new.toList()
+    private val oldSelectedTabIds = oldSelectedIds?.toList()
+    private val newSelectedIds = newSelectedIds?.toList()
 
     private fun areItemsTheSame(
         oldItem: TabEntity,
@@ -40,7 +47,8 @@ class TabEntityDiffCallback(old: List<TabEntity>, new: List<TabEntity>) : DiffUt
         return oldItem.tabPreviewFile == newItem.tabPreviewFile &&
             oldItem.viewed == newItem.viewed &&
             oldItem.title == newItem.title &&
-            oldItem.url == newItem.url
+            oldItem.url == newItem.url &&
+            oldSelectedTabIds?.contains(oldItem.tabId) == newSelectedIds?.contains(newItem.tabId)
     }
 
     private fun getChangePayload(
@@ -65,6 +73,10 @@ class TabEntityDiffCallback(old: List<TabEntity>, new: List<TabEntity>) : DiffUt
             diffBundle.putString(DIFF_KEY_PREVIEW, newItem.tabPreviewFile)
         }
 
+        if (oldSelectedTabIds?.contains(oldItem.tabId) != newSelectedIds?.contains(newItem.tabId)) {
+            diffBundle.putString(DIFF_KEY_SELECTION, newItem.tabId)
+        }
+
         return diffBundle
     }
 
@@ -105,5 +117,6 @@ class TabEntityDiffCallback(old: List<TabEntity>, new: List<TabEntity>) : DiffUt
         const val DIFF_KEY_URL = "url"
         const val DIFF_KEY_PREVIEW = "previewImage"
         const val DIFF_KEY_VIEWED = "viewed"
+        const val DIFF_KEY_SELECTION = "selection"
     }
 }

app/src/main/java/com/duckduckgo/app/tabs/ui/TabItemDecorator.kt

@@ -23,52 +23,77 @@ import android.graphics.RectF
 import android.util.TypedValue
 import android.view.View
 import androidx.core.content.ContextCompat
+import androidx.core.view.children
 import androidx.recyclerview.widget.RecyclerView
+import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.SelectionViewState.Mode
+import com.duckduckgo.app.tabs.ui.TabSwitcherViewModel.SelectionViewState.Mode.Normal
 import com.duckduckgo.common.ui.view.toPx
 import com.duckduckgo.mobile.android.R as CommonR
 
 class TabItemDecorator(
     context: Context,
-    var selectedTabId: String?,
+    val selectedTabId: String?,
+    private var mode: Mode = Normal,
 ) : RecyclerView.ItemDecoration() {
 
-    private val borderStroke: Paint = Paint().apply {
+    var highlightedTabId: String? = selectedTabId
+        private set
+
+    private val activeTabBorderStroke: Paint = Paint().apply {
         isAntiAlias = true
         style = Paint.Style.STROKE
-        strokeWidth = BORDER_WIDTH
+        strokeWidth = ACTIVE_TAB_BORDER_WIDTH
 
         val typedValue = TypedValue()
         context.theme.resolveAttribute(CommonR.attr.daxColorBackgroundInverted, typedValue, true)
         color = ContextCompat.getColor(context, typedValue.resourceId)
     }
 
+    private val selectionBorderStroke: Paint = Paint().apply {
+        isAntiAlias = true
+        style = Paint.Style.STROKE
+        strokeWidth = SELECTION_BORDER_WIDTH
+
+        val typedValue = TypedValue()
+        context.theme.resolveAttribute(CommonR.attr.daxColorAccentBlue, typedValue, true)
+        color = ContextCompat.getColor(context, typedValue.resourceId)
+    }
+
     override fun onDrawOver(
         canvas: Canvas,
         recyclerView: RecyclerView,
         state: RecyclerView.State,
     ) {
         val adapter = recyclerView.adapter as TabSwitcherAdapter? ?: return
-
-        for (i in 0 until recyclerView.childCount) {
-            val child = recyclerView.getChildAt(i)
-
+        recyclerView.children.forEach { child ->
             val positionInAdapter = recyclerView.getChildAdapterPosition(child)
             adapter.getTab(positionInAdapter)?.let { tab ->
-                if (tab.tabId == selectedTabId) {
-                    drawSelectedTabDecoration(child, canvas)
+                when (mode) {
+                    is Normal -> {
+                        if (tab.tabId == highlightedTabId) {
+                            drawTabDecoration(child, canvas, activeTabBorderStroke)
+                        }
+                    }
+                    is Mode.Selection -> {
+                        if (tab.tabId in (mode as Mode.Selection).selectedTabs) {
+                            drawTabDecoration(child, canvas, selectionBorderStroke)
+                        }
+                    }
                 }
             }
         }
 
         super.onDrawOver(canvas, recyclerView, state)
     }
 
-    private fun drawSelectedTabDecoration(
-        child: View,
-        c: Canvas,
-    ) {
-        borderStroke.alpha = (child.alpha * 255).toInt()
-        c.drawRoundRect(child.getBounds(), BORDER_RADIUS, BORDER_RADIUS, borderStroke)
+    fun updateParameters(selectedTabId: String?, mode: Mode = Normal) {
+        this.highlightedTabId = selectedTabId
+        this.mode = mode
+    }
+
+    private fun drawTabDecoration(child: View, c: Canvas, paint: Paint) {
+        selectionBorderStroke.alpha = (child.alpha * 255).toInt()
+        c.drawRoundRect(child.getBounds(), BORDER_RADIUS, BORDER_RADIUS, paint)
     }
 
     private fun View.getBounds(): RectF {
@@ -83,7 +108,8 @@ class TabItemDecorator(
 
     companion object {
         private val BORDER_RADIUS = 12.toPx().toFloat()
-        private val BORDER_WIDTH = 2.toPx().toFloat()
+        private val ACTIVE_TAB_BORDER_WIDTH = 2.toPx().toFloat()
+        private val SELECTION_BORDER_WIDTH = 4.toPx().toFloat()
         private val BORDER_PADDING = 3.toPx().toFloat()
     }
 }