Fix SwipeDetector positive vs negative for HORIZONTAL direction

Previously left was considered positive and right considered negative.
Now left and down are negative, and right and up are positive.

For RTL, left is positive and right is negative.

Change-Id: Ia31e8c687c8c2716fc632b2fe88aa8955b934bce

2 files changed, 60 insertions, 16 deletions

diff --git a/src/com/android/launcher3/touch/AbstractStateChangeTouchController.java b/src/com/android/launcher3/touch/AbstractStateChangeTouchController.java
index 86deb43e0..40b030f62 100644
--- a/src/com/android/launcher3/touch/AbstractStateChangeTouchController.java
+++ b/src/com/android/launcher3/touch/AbstractStateChangeTouchController.java
@@ -69,6 +69,7 @@ public abstract class AbstractStateChangeTouchController
 
     protected final Launcher mLauncher;
     protected final SwipeDetector mDetector;
+    protected final SwipeDetector.Direction mSwipeDirection;
 
     private boolean mNoIntercept;
     protected int mStartContainerType;
@@ -105,6 +106,7 @@ public abstract class AbstractStateChangeTouchController
     public AbstractStateChangeTouchController(Launcher l, SwipeDetector.Direction dir) {
         mLauncher = l;
         mDetector = new SwipeDetector(l, this, dir);
+        mSwipeDirection = dir;
     }
 
     protected long getAtomicDuration() {
@@ -262,7 +264,8 @@ public abstract class AbstractStateChangeTouchController
         float deltaProgress = mProgressMultiplier * (displacement - mDisplacementShift);
         float progress = deltaProgress + mStartProgress;
         updateProgress(progress);
-        boolean isDragTowardPositive = (displacement - mDisplacementShift) < 0;
+        boolean isDragTowardPositive = mSwipeDirection.isPositive(
+                displacement - mDisplacementShift);
         if (progress <= 0) {
             if (reinitCurrentAnimation(false, isDragTowardPositive)) {
                 mDisplacementShift = displacement;
diff --git a/src/com/android/launcher3/touch/SwipeDetector.java b/src/com/android/launcher3/touch/SwipeDetector.java
index a0a410e0d..e558fc7c7 100644
--- a/src/com/android/launcher3/touch/SwipeDetector.java
+++ b/src/com/android/launcher3/touch/SwipeDetector.java
@@ -24,6 +24,8 @@ import android.view.MotionEvent;
 import android.view.VelocityTracker;
 import android.view.ViewConfiguration;
 
+import com.android.launcher3.Utilities;
+
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
 
@@ -64,20 +66,25 @@ public class SwipeDetector {
 
     public static abstract class Direction {
 
-        abstract float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint);
+        abstract float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint,
+                boolean isRtl);
 
         /**
          * Distance in pixels a touch can wander before we think the user is scrolling.
          */
         abstract float getActiveTouchSlop(MotionEvent ev, int pointerIndex, PointF downPos);
 
-        abstract float getVelocity(VelocityTracker tracker);
+        abstract float getVelocity(VelocityTracker tracker, boolean isRtl);
+
+        abstract boolean isPositive(float displacement);
+
+        abstract boolean isNegative(float displacement);
     }
 
     public static final Direction VERTICAL = new Direction() {
 
         @Override
-        float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint) {
+        float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint, boolean isRtl) {
             return ev.getY(pointerIndex) - refPoint.y;
         }
 
@@ -87,16 +94,32 @@ public class SwipeDetector {
         }
 
         @Override
-        float getVelocity(VelocityTracker tracker) {
+        float getVelocity(VelocityTracker tracker, boolean isRtl) {
             return tracker.getYVelocity();
         }
+
+        @Override
+        boolean isPositive(float displacement) {
+            // Up
+            return displacement < 0;
+        }
+
+        @Override
+        boolean isNegative(float displacement) {
+            // Down
+            return displacement > 0;
+        }
     };
 
     public static final Direction HORIZONTAL = new Direction() {
 
         @Override
-        float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint) {
-            return ev.getX(pointerIndex) - refPoint.x;
+        float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint, boolean isRtl) {
+            float displacement = ev.getX(pointerIndex) - refPoint.x;
+            if (isRtl) {
+                displacement = -displacement;
+            }
+            return displacement;
         }
 
         @Override
@@ -105,8 +128,24 @@ public class SwipeDetector {
         }
 
         @Override
-        float getVelocity(VelocityTracker tracker) {
-            return tracker.getXVelocity();
+        float getVelocity(VelocityTracker tracker, boolean isRtl) {
+            float velocity = tracker.getXVelocity();
+            if (isRtl) {
+                velocity = -velocity;
+            }
+            return velocity;
+        }
+
+        @Override
+        boolean isPositive(float displacement) {
+            // Right
+            return displacement > 0;
+        }
+
+        @Override
+        boolean isNegative(float displacement) {
+            // Left
+            return displacement < 0;
         }
     };
 
@@ -159,6 +198,7 @@ public class SwipeDetector {
     private final PointF mDownPos = new PointF();
     private final PointF mLastPos = new PointF();
     private final Direction mDir;
+    private final boolean mIsRtl;
 
     private final float mTouchSlop;
     private final float mMaxVelocity;
@@ -183,14 +223,15 @@ public class SwipeDetector {
     }
 
     public SwipeDetector(@NonNull Context context, @NonNull Listener l, @NonNull Direction dir) {
-        this(ViewConfiguration.get(context), l, dir);
+        this(ViewConfiguration.get(context), l, dir, Utilities.isRtl(context.getResources()));
     }
 
     @VisibleForTesting
     protected SwipeDetector(@NonNull ViewConfiguration config, @NonNull Listener l,
-            @NonNull Direction dir) {
+            @NonNull Direction dir, boolean isRtl) {
         mListener = l;
         mDir = dir;
+        mIsRtl = isRtl;
         mTouchSlop = config.getScaledTouchSlop();
         mMaxVelocity = config.getScaledMaximumFlingVelocity();
     }
@@ -212,8 +253,8 @@ public class SwipeDetector {
         }
 
         // Check if the client is interested in scroll in current direction.
-        if (((mScrollConditions & DIRECTION_NEGATIVE) > 0 && mDisplacement > 0) ||
-                ((mScrollConditions & DIRECTION_POSITIVE) > 0 && mDisplacement < 0)) {
+        if (((mScrollConditions & DIRECTION_NEGATIVE) > 0 && mDir.isNegative(mDisplacement)) ||
+                ((mScrollConditions & DIRECTION_POSITIVE) > 0 && mDir.isPositive(mDisplacement))) {
             return true;
         }
         return false;
@@ -259,7 +300,7 @@ public class SwipeDetector {
                 if (pointerIndex == INVALID_POINTER_ID) {
                     break;
                 }
-                mDisplacement = mDir.getDisplacement(ev, pointerIndex, mDownPos);
+                mDisplacement = mDir.getDisplacement(ev, pointerIndex, mDownPos, mIsRtl);
 
                 // handle state and listener calls.
                 if (mState != ScrollState.DRAGGING && shouldScrollStart(ev, pointerIndex)) {
@@ -315,7 +356,7 @@ public class SwipeDetector {
      * @see #DIRECTION_BOTH
      */
     public boolean wasInitialTouchPositive() {
-        return mSubtractDisplacement < 0;
+        return mDir.isPositive(mSubtractDisplacement);
     }
 
     private boolean reportDragging() {
@@ -332,7 +373,7 @@ public class SwipeDetector {
 
     private void reportDragEnd() {
         mVelocityTracker.computeCurrentVelocity(1000, mMaxVelocity);
-        float velocity = mDir.getVelocity(mVelocityTracker) / 1000;
+        float velocity = mDir.getVelocity(mVelocityTracker, mIsRtl) / 1000;
         if (DBG) {
             Log.d(TAG, String.format("onScrollEnd disp=%.1f, velocity=%.1f",
                     mDisplacement, velocity));