From e97b0ecadcd42b3dbe2415cd8529f50d4f314a98 Mon Sep 17 00:00:00 2001
From: Nikita Dubrovsky <dubrovsky@google.com>
Date: Mon, 22 Jun 2020 15:26:25 -0700
Subject: [PATCH] Fix double-tap detection in TextView's
 SelectionModifierCursorController

This restores the logic removed from SelectionModifierCursorController
in ag/9994946. A quick sequence of "tap", "drag", "tap" events (such
as when quickly scrolling a small input field) should *not* be treated
as a double-tap.

Bug: 158948887
Test: Manual and unit tests
  atest FrameworksCoreTests:EditorTouchStateTest
  atest FrameworksCoreTests:EditorCursorDragTest
Change-Id: I9fb9cb06b1e208946566a0f70697c62ee7684ca0
---
 core/java/android/widget/Editor.java | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/core/java/android/widget/Editor.java b/core/java/android/widget/Editor.java
index 51d37a53f21f6..07a721f5a9c91 100644
--- a/core/java/android/widget/Editor.java
+++ b/core/java/android/widget/Editor.java
@@ -6354,6 +6354,8 @@ public class Editor {
         // The offsets of that last touch down event. Remembered to start selection there.
         private int mMinTouchOffset, mMaxTouchOffset;
 
+        private boolean mGestureStayedInTapRegion;
+
         // Where the user first starts the drag motion.
         private int mStartOffset = -1;
 
@@ -6460,8 +6462,10 @@ public class Editor {
                                 eventX, eventY);
 
                         // Double tap detection
-                        if (mTouchState.isMultiTapInSameArea() && (isMouse
-                                || mTouchState.isOnHandle() || isPositionOnText(eventX, eventY))) {
+                        if (mGestureStayedInTapRegion
+                                && mTouchState.isMultiTapInSameArea()
+                                && (isMouse || isPositionOnText(eventX, eventY)
+                                || mTouchState.isOnHandle())) {
                             if (TextView.DEBUG_CURSOR) {
                                 logCursor("SelectionModifierCursorController: onTouchEvent",
                                         "ACTION_DOWN: select and start drag");
@@ -6473,6 +6477,7 @@ public class Editor {
                             }
                             mDiscardNextActionUp = true;
                         }
+                        mGestureStayedInTapRegion = true;
                         mHaventMovedEnoughToStartDrag = true;
                     }
                     break;
@@ -6488,6 +6493,14 @@ public class Editor {
                     break;
 
                 case MotionEvent.ACTION_MOVE:
+                    if (mGestureStayedInTapRegion) {
+                        final ViewConfiguration viewConfig = ViewConfiguration.get(
+                                mTextView.getContext());
+                        mGestureStayedInTapRegion = EditorTouchState.isDistanceWithin(
+                                mTouchState.getLastDownX(), mTouchState.getLastDownY(),
+                                eventX, eventY, viewConfig.getScaledDoubleTapTouchSlop());
+                    }
+
                     if (mHaventMovedEnoughToStartDrag) {
                         mHaventMovedEnoughToStartDrag = !mTouchState.isMovedEnoughForDrag();
                     }