2 files changed, 21 insertions, 20 deletions

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/back/TouchTracker.java b/libs/WindowManager/Shell/src/com/android/wm/shell/back/TouchTracker.java
index 8a59a9f62425..19eb928d4e30 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/back/TouchTracker.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/back/TouchTracker.java
@@ -51,7 +51,6 @@ class TouchTracker {
     private float mLatestVelocityY;
     private float mStartThresholdX;
     private int mSwipeEdge;
-    private boolean mCancelled;
     private TouchTrackerState mState = TouchTrackerState.INITIAL;
 
     void update(float touchX, float touchY, float velocityX, float velocityY) {
@@ -59,9 +58,8 @@ class TouchTracker {
          * If back was previously cancelled but the user has started swiping in the forward
          * direction again, restart back.
          */
-        if (mCancelled && ((touchX > mLatestTouchX && mSwipeEdge == BackEvent.EDGE_LEFT)
-                || touchX < mLatestTouchX && mSwipeEdge == BackEvent.EDGE_RIGHT)) {
-            mCancelled = false;
+        if ((touchX < mStartThresholdX && mSwipeEdge == BackEvent.EDGE_LEFT)
+                || (touchX > mStartThresholdX && mSwipeEdge == BackEvent.EDGE_RIGHT)) {
             mStartThresholdX = touchX;
         }
         mLatestTouchX = touchX;
@@ -72,7 +70,7 @@ class TouchTracker {
 
     void setTriggerBack(boolean triggerBack) {
         if (mTriggerBack != triggerBack && !triggerBack) {
-            mCancelled = true;
+            mStartThresholdX = mLatestTouchX;
         }
         mTriggerBack = triggerBack;
     }
@@ -100,6 +98,8 @@ class TouchTracker {
     void setGestureStartLocation(float touchX, float touchY, int swipeEdge) {
         mInitTouchX = touchX;
         mInitTouchY = touchY;
+        mLatestTouchX = touchX;
+        mLatestTouchY = touchY;
         mSwipeEdge = swipeEdge;
         mStartThresholdX = mInitTouchX;
     }
@@ -108,7 +108,6 @@ class TouchTracker {
         mInitTouchX = 0;
         mInitTouchY = 0;
         mStartThresholdX = 0;
-        mCancelled = false;
         mTriggerBack = false;
         mState = TouchTrackerState.INITIAL;
         mSwipeEdge = BackEvent.EDGE_LEFT;
@@ -126,11 +125,7 @@ class TouchTracker {
     }
 
     BackMotionEvent createProgressEvent() {
-        float progress = 0;
-        // Progress is always 0 when back is cancelled and not restarted.
-        if (!mCancelled) {
-            progress = getProgress(mLatestTouchX);
-        }
+        float progress = getProgress(mLatestTouchX);
         return createProgressEvent(progress);
     }
 
@@ -148,7 +143,13 @@ class TouchTracker {
         // The starting threshold is initially the first touch location, and updated to
         // the location everytime back is restarted after being cancelled.
         float startX = mTriggerBack ? mInitTouchX : mStartThresholdX;
-        float deltaX = Math.abs(startX - touchX);
+        float distance;
+        if (mSwipeEdge == BackEvent.EDGE_LEFT) {
+            distance = touchX - startX;
+        } else {
+            distance = startX - touchX;
+        }
+        float deltaX = Math.max(0f, distance);
         float linearDistance = mLinearDistance;
         float maxDistance = getMaxDistance();
         maxDistance = maxDistance == 0 ? 1 : maxDistance;
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/back/TouchTrackerTest.kt b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/back/TouchTrackerTest.kt
index 9088e8997e79..bf07dccd0658 100644
--- a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/back/TouchTrackerTest.kt
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/back/TouchTrackerTest.kt
@@ -71,13 +71,13 @@ class TouchTrackerTest {
         linearTracker.update(touchX, 0f, velocityX, velocityY)
         linearTracker.assertProgress(0f)
 
-        // Restart
+        // Restarted, but pre-commit
+        val restartX = touchX
         touchX += 10f
         linearTracker.update(touchX, 0f, velocityX, velocityY)
-        linearTracker.assertProgress(0f)
+        linearTracker.assertProgress((touchX - restartX) / MAX_DISTANCE)
 
-        // Restarted, but pre-commit
-        val restartX = touchX
+        // continue restart within pre-commit
         touchX += 10f
         linearTracker.update(touchX, 0f, velocityX, velocityY)
         linearTracker.assertProgress((touchX - restartX) / MAX_DISTANCE)
@@ -119,13 +119,13 @@ class TouchTrackerTest {
         linearTracker.update(touchX, 0f, velocityX, velocityY)
         linearTracker.assertProgress(0f)
 
-        // Restart
+        // Restarted, but pre-commit
+        val restartX = touchX
         touchX -= 10f
         linearTracker.update(touchX, 0f, velocityX, velocityY)
-        linearTracker.assertProgress(0f)
+        linearTracker.assertProgress((restartX - touchX) / target)
 
-        // Restarted, but pre-commit
-        val restartX = touchX
+        // continue restart within pre-commit
         touchX -= 10f
         linearTracker.update(touchX, 0f, velocityX, velocityY)
         linearTracker.assertProgress((restartX - touchX) / target)