Merge "Filter out position jitter in hover tooltip handling"

2 files changed, 49 insertions, 3 deletions

diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index ab5372a6b0ac..02beee05811b 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -4299,6 +4299,38 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
          */
         Runnable mShowTooltipRunnable;
         Runnable mHideTooltipRunnable;
+
+        /**
+         * Hover move is ignored if it is within this distance in pixels from the previous one.
+         */
+        int mHoverSlop;
+
+        /**
+         * Update the anchor position if it significantly (that is by at least mHoverSlop)
+         * different from the previously stored position. Ignoring insignificant changes
+         * filters out the jitter which is typical for such input sources as stylus.
+         *
+         * @return True if the position has been updated.
+         */
+        private boolean updateAnchorPos(MotionEvent event) {
+            final int newAnchorX = (int) event.getX();
+            final int newAnchorY = (int) event.getY();
+            if (Math.abs(newAnchorX - mAnchorX) <= mHoverSlop
+                    && Math.abs(newAnchorY - mAnchorY) <= mHoverSlop) {
+                return false;
+            }
+            mAnchorX = newAnchorX;
+            mAnchorY = newAnchorY;
+            return true;
+        }
+
+        /**
+         *  Clear the anchor position to ensure that the next change is considered significant.
+         */
+        private void clearAnchorPos() {
+            mAnchorX = Integer.MAX_VALUE;
+            mAnchorY = Integer.MAX_VALUE;
+        }
     }
 
     TooltipInfo mTooltipInfo;
@@ -26816,6 +26848,8 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
                 mTooltipInfo = new TooltipInfo();
                 mTooltipInfo.mShowTooltipRunnable = this::showHoverTooltip;
                 mTooltipInfo.mHideTooltipRunnable = this::hideTooltip;
+                mTooltipInfo.mHoverSlop = ViewConfiguration.get(mContext).getScaledHoverSlop();
+                mTooltipInfo.clearAnchorPos();
             }
             mTooltipInfo.mTooltipText = tooltipText;
         }
@@ -26882,6 +26916,7 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         mTooltipInfo.mTooltipPopup.hide();
         mTooltipInfo.mTooltipPopup = null;
         mTooltipInfo.mTooltipFromLongClick = false;
+        mTooltipInfo.clearAnchorPos();
         if (mAttachInfo != null) {
             mAttachInfo.mTooltipHost = null;
         }
@@ -26906,11 +26941,9 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
                 if ((mViewFlags & TOOLTIP) != TOOLTIP || (mViewFlags & ENABLED_MASK) != ENABLED) {
                     break;
                 }
-                if (!mTooltipInfo.mTooltipFromLongClick) {
+                if (!mTooltipInfo.mTooltipFromLongClick && mTooltipInfo.updateAnchorPos(event)) {
                     if (mTooltipInfo.mTooltipPopup == null) {
                         // Schedule showing the tooltip after a timeout.
-                        mTooltipInfo.mAnchorX = (int) event.getX();
-                        mTooltipInfo.mAnchorY = (int) event.getY();
                         removeCallbacks(mTooltipInfo.mShowTooltipRunnable);
                         postDelayed(mTooltipInfo.mShowTooltipRunnable,
                                 ViewConfiguration.getHoverTooltipShowTimeout());
@@ -26932,6 +26965,7 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
                 return true;
 
             case MotionEvent.ACTION_HOVER_EXIT:
+                mTooltipInfo.clearAnchorPos();
                 if (!mTooltipInfo.mTooltipFromLongClick) {
                     hideTooltip();
                 }
diff --git a/core/java/android/view/ViewConfiguration.java b/core/java/android/view/ViewConfiguration.java
index c44c8dda83a9..c5a94daaba53 100644
--- a/core/java/android/view/ViewConfiguration.java
+++ b/core/java/android/view/ViewConfiguration.java
@@ -290,6 +290,7 @@ public class ViewConfiguration {
     private final int mMaximumFlingVelocity;
     private final int mScrollbarSize;
     private final int mTouchSlop;
+    private final int mHoverSlop;
     private final int mMinScrollbarTouchTarget;
     private final int mDoubleTapTouchSlop;
     private final int mPagingTouchSlop;
@@ -320,6 +321,7 @@ public class ViewConfiguration {
         mMaximumFlingVelocity = MAXIMUM_FLING_VELOCITY;
         mScrollbarSize = SCROLL_BAR_SIZE;
         mTouchSlop = TOUCH_SLOP;
+        mHoverSlop = TOUCH_SLOP / 2;
         mMinScrollbarTouchTarget = MIN_SCROLLBAR_TOUCH_TARGET;
         mDoubleTapTouchSlop = DOUBLE_TAP_TOUCH_SLOP;
         mPagingTouchSlop = PAGING_TOUCH_SLOP;
@@ -407,6 +409,8 @@ public class ViewConfiguration {
                 com.android.internal.R.bool.config_ui_enableFadingMarquee);
         mTouchSlop = res.getDimensionPixelSize(
                 com.android.internal.R.dimen.config_viewConfigurationTouchSlop);
+        mHoverSlop = res.getDimensionPixelSize(
+                com.android.internal.R.dimen.config_viewConfigurationHoverSlop);
         mMinScrollbarTouchTarget = res.getDimensionPixelSize(
                 com.android.internal.R.dimen.config_minScrollbarTouchTarget);
         mPagingTouchSlop = mTouchSlop * 2;
@@ -640,6 +644,14 @@ public class ViewConfiguration {
     }
 
     /**
+     * @return Distance in pixels a hover can wander while it is still considered "stationary".
+     *
+     */
+    public int getScaledHoverSlop() {
+        return mHoverSlop;
+    }
+
+    /**
      * @return Distance in pixels the first touch can wander before we do not consider this a
      * potential double tap event
      * @hide