From ba55296a448efc2a3789ef6f3a7d2e438513454e Mon Sep 17 00:00:00 2001
From: John Li <lijohn@google.com>
Date: Fri, 11 Dec 2020 16:13:24 +0800
Subject: [PATCH] Haptic effect on swiping the notification item

Haptic once the swiping on the notification item is going to snap in either directions. The snap-in scenario is about the notification item when there is a "snap back point" i.e. if swiping the item back till a certain point it just snaps back to initial state but once it goes past a certain location it snaps into the new location.

- screenshot, https://screenshot.googleplex.com/6A8Gxs7yRwqAVk2

Bug: 175364588
Test: manual
Change-Id: I7e2ed19bfb7f863502e10233e3e23ee5d434b3b4
---
 .../NotificationHistoryRecyclerView.java      | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/com/android/settings/notification/history/NotificationHistoryRecyclerView.java b/src/com/android/settings/notification/history/NotificationHistoryRecyclerView.java
index 5a6ff7e781d..06c74bc3432 100644
--- a/src/com/android/settings/notification/history/NotificationHistoryRecyclerView.java
+++ b/src/com/android/settings/notification/history/NotificationHistoryRecyclerView.java
@@ -1,9 +1,14 @@
 package com.android.settings.notification.history;
 
+import static android.view.HapticFeedbackConstants.CLOCK_TICK;
+
 import android.annotation.Nullable;
 import android.content.Context;
+import android.graphics.Canvas;
 import android.util.AttributeSet;
+import android.view.View;
 
+import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.DividerItemDecoration;
 import androidx.recyclerview.widget.ItemTouchHelper;
 import androidx.recyclerview.widget.LinearLayoutManager;
@@ -15,6 +20,9 @@ public class NotificationHistoryRecyclerView extends RecyclerView {
 
     private OnItemSwipeDeleteListener listener;
 
+    /** The amount of horizontal displacement caused by user's action, used to track the swiping. */
+    private float dXLast;
+
     public NotificationHistoryRecyclerView(Context context) {
         this(context, null);
     }
@@ -57,6 +65,27 @@ public class NotificationHistoryRecyclerView extends RecyclerView {
                 listener.onItemSwipeDeleted(viewHolder.getAdapterPosition());
             }
         }
+
+        /** Performs haptic effect once the swiping goes past a certain location. */
+        @Override
+        public void onChildDraw(@NonNull Canvas c, @NonNull RecyclerView recyclerView,
+                @NonNull ViewHolder viewHolder, float dX, float dY, int actionState,
+                boolean isCurrentlyActive) {
+            super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
+            if (isCurrentlyActive) {
+                View view = viewHolder.itemView;
+                float swipeThreshold = getSwipeThreshold(viewHolder);
+                float snapOffset = swipeThreshold * view.getWidth();
+                boolean snapIntoNewLocation = dX < -snapOffset || dX > snapOffset;
+                boolean snapIntoNewLocationLast = dXLast < -snapOffset || dXLast > snapOffset;
+                if (snapIntoNewLocation != snapIntoNewLocationLast) {
+                    view.performHapticFeedback(CLOCK_TICK);
+                }
+                dXLast = dX;
+            } else {
+                dXLast = 0;
+            }
+        }
     }
 
     public interface OnItemSwipeDeleteListener {