From b7240136b748e548069c7fe2bd77a7ed4148728e Mon Sep 17 00:00:00 2001
From: Jorim Jaggi <jjaggi@google.com>
Date: Mon, 30 Jun 2014 01:39:07 +0200
Subject: [PATCH] Improve fling logic for opening the notification shade

Bug: 15858126
Change-Id: I800b00f80b315218358ea9acbd3614e6d5c87c45
---
 .../systemui/statusbar/phone/PanelView.java        | 35 ++++++++++++----------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelView.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelView.java
index c5924867c3c8..7093787a2bd0 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelView.java
@@ -195,7 +195,12 @@ public abstract class PanelView extends FrameLayout {
 
             case MotionEvent.ACTION_MOVE:
                 float h = y - mInitialTouchY;
-                if (Math.abs(h) > mTouchSlop && Math.abs(h) > Math.abs(x - mInitialTouchX)) {
+
+                // If the panel was collapsed when touching, we only need to check for the
+                // y-component of the gesture, as we have no conflicting horizontal gesture.
+                if (Math.abs(h) > mTouchSlop
+                        && (Math.abs(h) > Math.abs(x - mInitialTouchX)
+                                || mInitialOffsetOnTouch == 0f)) {
                     mTouchSlopExceeded = true;
                     if (waitForTouchSlop && !mTracking) {
                         mInitialOffsetOnTouch = mExpandedHeight;
@@ -229,8 +234,15 @@ public abstract class PanelView extends FrameLayout {
                 trackMovement(event);
                 if ((mTracking && mTouchSlopExceeded)
                         || event.getActionMasked() == MotionEvent.ACTION_CANCEL) {
-                    float vel = getCurrentVelocity();
-                    boolean expand = flingExpands(vel);
+                    float vel = 0f;
+                    float vectorVel = 0f;
+                    if (mVelocityTracker != null) {
+                        mVelocityTracker.computeCurrentVelocity(1000);
+                        vel = mVelocityTracker.getYVelocity();
+                        vectorVel = (float) Math.hypot(
+                                mVelocityTracker.getXVelocity(), mVelocityTracker.getYVelocity());
+                    }
+                    boolean expand = flingExpands(vel, vectorVel);
                     onTrackingStopped(expand);
                     fling(vel, expand);
                 } else {
@@ -259,16 +271,6 @@ public abstract class PanelView extends FrameLayout {
         onExpandingStarted();
     }
 
-    private float getCurrentVelocity() {
-
-        // the velocitytracker might be null if we got a bad input stream
-        if (mVelocityTracker == null) {
-            return 0;
-        }
-        mVelocityTracker.computeCurrentVelocity(1000);
-        return mVelocityTracker.getYVelocity();
-    }
-
     @Override
     public boolean onInterceptTouchEvent(MotionEvent event) {
         if (mInstantExpanding) {
@@ -368,11 +370,12 @@ public abstract class PanelView extends FrameLayout {
     }
 
     /**
-     * @param vel the current velocity of the motion
+     * @param vel the current vertical velocity of the motion
+     * @param vectorVel the length of the vectorial velocity
      * @return whether a fling should expands the panel; contracts otherwise
      */
-    private boolean flingExpands(float vel) {
-        if (Math.abs(vel) < mFlingAnimationUtils.getMinVelocityPxPerSecond()) {
+    private boolean flingExpands(float vel, float vectorVel) {
+        if (Math.abs(vectorVel) < mFlingAnimationUtils.getMinVelocityPxPerSecond()) {
             return getExpandedFraction() > 0.5f;
         } else {
             return vel > 0;
-- 
2.11.0