commit 2e564400ba6282a8fd12d20f4f8749c7c4e98853
author Tony Mak <tonymak@google.com> Tue Feb 27 17:19:34 2018 +0000
committer Tony Mak <tonymak@google.com> Tue Feb 27 17:29:12 2018 +0000
tree 6eb3881b2ecdb6cea28719aa1bbda4ce2fb725ad
parent 7eadfc4f150ed6fd3877249847740624ab671031

Fix all apps tab fling detection

It is a regression when we changed from ViewPager to PagedView.
Unlike ViewPager, PagedView does not take "yDiff" into account
when determining should it intercept its child MotionEvent.

Override determineScrollingStart, just like what we did in Workspace

Change-Id: I25f7415c45c370629558d944f59bf95c741b9319
FIX: 73878167

src/com/android/launcher3/PagedView.java

diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index ccb0a95..4be32b2 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -1892,6 +1892,14 @@
                 getNextPage() + 1, getChildCount());
     }
 
+    protected float getDownMotionX() {
+        return mDownMotionX;
+    }
+
+    protected float getDownMotionY() {
+        return mDownMotionY;
+    }
+
     @Override
     public boolean onHoverEvent(android.view.MotionEvent event) {
         return true;

src/com/android/launcher3/allapps/AllAppsPagedView.java

diff --git a/src/com/android/launcher3/allapps/AllAppsPagedView.java b/src/com/android/launcher3/allapps/AllAppsPagedView.java
index 86186fd..3b4450b 100644
--- a/src/com/android/launcher3/allapps/AllAppsPagedView.java
+++ b/src/com/android/launcher3/allapps/AllAppsPagedView.java
@@ -18,12 +18,17 @@
 import android.content.Context;
 import android.util.AttributeSet;
 
+import android.view.MotionEvent;
 import com.android.launcher3.PagedView;
 import com.android.launcher3.R;
 
 public class AllAppsPagedView extends PagedView<PersonalWorkSlidingTabStrip> {
 
-    public AllAppsPagedView(Context context) {
+  final static float START_DAMPING_TOUCH_SLOP_ANGLE = (float) Math.PI / 6;
+  final static float MAX_SWIPE_ANGLE = (float) Math.PI / 3;
+  final static float TOUCH_SLOP_DAMPING_FACTOR = 4;
+
+  public AllAppsPagedView(Context context) {
         this(context, null);
     }
 
@@ -46,4 +51,30 @@
         super.onScrollChanged(l, t, oldl, oldt);
         mPageIndicator.setScroll(l, mMaxScrollX);
     }
+
+    @Override
+    protected void determineScrollingStart(MotionEvent ev) {
+        float absDeltaX = Math.abs(ev.getX() - getDownMotionX());
+        float absDeltaY = Math.abs(ev.getY() - getDownMotionY());
+
+        if (Float.compare(absDeltaX, 0f) == 0) return;
+
+        float slope = absDeltaY / absDeltaX;
+        float theta = (float) Math.atan(slope);
+
+        if (absDeltaX > mTouchSlop || absDeltaY > mTouchSlop) {
+            cancelCurrentPageLongPress();
+        }
+
+        if (theta > MAX_SWIPE_ANGLE) {
+            return;
+        } else if (theta > START_DAMPING_TOUCH_SLOP_ANGLE) {
+            theta -= START_DAMPING_TOUCH_SLOP_ANGLE;
+            float extraRatio = (float)
+                    Math.sqrt((theta / (MAX_SWIPE_ANGLE - START_DAMPING_TOUCH_SLOP_ANGLE)));
+            super.determineScrollingStart(ev, 1 + TOUCH_SLOP_DAMPING_FACTOR * extraRatio);
+        } else {
+            super.determineScrollingStart(ev);
+        }
+    }
 }