Adjusted the behavior when expanding the notification panel

The topmost notification is now not collapsed anymore but slides in
expanded from the top. Therefore it's layout doesn't need to animate
anymore. This also cleans up a lot of code in the algorithm which was
depending on this resizing which isn't needed anymore.
In order to have that transition working perfectly, the padding when
collapsing a card is now the same as the slowdown length.
Also improved the logic when notification contents are allowed to
animate and when not.
Also fixed a bug where the top notification was cut off when QS was
expanded.

Bug: 27402534
Bug: 18434284
Change-Id: I31afa199d38d94e74fd45500c2236ffdb51d989d

5 files changed, 32 insertions, 145 deletions

diff --git a/packages/SystemUI/res/values/dimens.xml b/packages/SystemUI/res/values/dimens.xml
index fbe0207a1a1c..8a7f90bf4a14 100644
--- a/packages/SystemUI/res/values/dimens.xml
+++ b/packages/SystemUI/res/values/dimens.xml
@@ -326,9 +326,6 @@
     <!-- The minimum amount of top overscroll to go to the quick settings. -->
     <dimen name="min_top_overscroll_to_qs">36dp</dimen>
 
-    <!-- The padding to the second card when the notifications collapse. -->
-    <dimen name="notification_collapse_second_card_padding">8dp</dimen>
-
     <!-- The height of the speed bump view. -->
     <dimen name="speed_bump_height">16dp</dimen>
 
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/NotificationContentView.java b/packages/SystemUI/src/com/android/systemui/statusbar/NotificationContentView.java
index 7c1116170ec3..61105f8ea12a 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/NotificationContentView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/NotificationContentView.java
@@ -92,7 +92,14 @@ public class NotificationContentView extends FrameLayout {
             = new ViewTreeObserver.OnPreDrawListener() {
         @Override
         public boolean onPreDraw() {
-            mAnimate = true;
+            // We need to post since we don't want the notification to animate on the very first
+            // frame
+            post(new Runnable() {
+                @Override
+                public void run() {
+                    mAnimate = true;
+                }
+            });
             getViewTreeObserver().removeOnPreDrawListener(this);
             return true;
         }
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
index 127febae5ee8..88b8afae3079 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
@@ -1397,7 +1397,7 @@ public class NotificationPanelView extends PanelView implements
                 // In Shade, interpolate linearly such that QS is closed whenever panel height is
                 // minimum QS expansion + minStackHeight
                 float panelHeightQsCollapsed = mNotificationStackScroller.getIntrinsicPadding()
-                        + mNotificationStackScroller.getMinStackHeight();
+                        + mNotificationStackScroller.getLayoutMinHeight();
                 float panelHeightQsExpanded = calculatePanelHeightQsExpanded();
                 t = (expandedHeight - panelHeightQsCollapsed)
                         / (panelHeightQsExpanded - panelHeightQsCollapsed);
@@ -1453,7 +1453,7 @@ public class NotificationPanelView extends PanelView implements
                 && mShadeEmpty) {
             notificationHeight = mNotificationStackScroller.getEmptyShadeViewHeight()
                     + mNotificationStackScroller.getBottomStackPeekSize()
-                    + mNotificationStackScroller.getCollapseSecondCardPadding();
+                    + mNotificationStackScroller.getBottomStackSlowDownHeight();
         }
         int maxQsHeight = mQsMaxExpansionHeight;
 
@@ -1468,7 +1468,7 @@ public class NotificationPanelView extends PanelView implements
                 + notificationHeight;
         if (totalHeight > mNotificationStackScroller.getHeight()) {
             float fullyCollapsedHeight = maxQsHeight
-                    + mNotificationStackScroller.getMinStackHeight();
+                    + mNotificationStackScroller.getLayoutMinHeight();
             totalHeight = Math.max(fullyCollapsedHeight, mNotificationStackScroller.getHeight());
         }
         return (int) totalHeight;
@@ -1485,7 +1485,7 @@ public class NotificationPanelView extends PanelView implements
     private float getFadeoutAlpha() {
         float alpha = (getNotificationsTopY() + mNotificationStackScroller.getFirstItemMinHeight())
                 / (mQsMinExpansionHeight + mNotificationStackScroller.getBottomStackPeekSize()
-                - mNotificationStackScroller.getCollapseSecondCardPadding());
+                - mNotificationStackScroller.getBottomStackSlowDownHeight());
         alpha = Math.max(0, Math.min(alpha, 1));
         alpha = (float) Math.pow(alpha, 0.75);
         return alpha;
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/stack/NotificationStackScrollLayout.java b/packages/SystemUI/src/com/android/systemui/statusbar/stack/NotificationStackScrollLayout.java
index 85b14264837d..e8dad92e7b19 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/stack/NotificationStackScrollLayout.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/stack/NotificationStackScrollLayout.java
@@ -418,12 +418,9 @@ public class NotificationStackScrollLayout extends ViewGroup
                 .getDimensionPixelSize(R.dimen.notification_divider_height));
         mIncreasedPaddingBetweenElements = context.getResources()
                 .getDimensionPixelSize(R.dimen.notification_divider_height_increased);
-
         mBottomStackSlowDownHeight = mStackScrollAlgorithm.getBottomStackSlowDownLength();
         mMinTopOverScrollToEscape = getResources().getDimensionPixelSize(
                 R.dimen.min_top_overscroll_to_qs);
-        mCollapseSecondCardPadding = getResources().getDimensionPixelSize(
-                R.dimen.notification_collapse_second_card_padding);
     }
 
     private void notifyHeightChangeListener(ExpandableView view) {
@@ -509,14 +506,6 @@ public class NotificationStackScrollLayout extends ViewGroup
     }
 
     /**
-     * @return whether the height of the layout needs to be adapted, in order to ensure that the
-     *         last child is not in the bottom stack.
-     */
-    private boolean needsHeightAdaption() {
-        return getNotGoneChildCount() > 1;
-    }
-
-    /**
      * Updates the children views according to the stack scroll algorithm. Call this whenever
      * modifications to {@link #mOwnScrollY} are performed to reflect it in the view layout.
      */
@@ -599,7 +588,7 @@ public class NotificationStackScrollLayout extends ViewGroup
         mLastSetStackHeight = height;
         setIsExpanded(height > 0.0f);
         int newStackHeight = (int) height;
-        int minStackHeight = getMinStackHeight();
+        int minStackHeight = getLayoutMinHeight();
         int stackHeight;
         float paddingOffset;
         boolean trackingHeadsUp = mTrackingHeadsUp || mHeadsUpManager.hasPinnedHeadsUp();
@@ -612,20 +601,7 @@ public class NotificationStackScrollLayout extends ViewGroup
             stackHeight = newStackHeight;
         } else {
             int translationY;
-            if (!trackingHeadsUp) {
-                // We did not reach the position yet where we actually start growing,
-                // so we translate the stack upwards.
-                translationY = (newStackHeight - minStackHeight);
-                // A slight parallax effect is introduced in order for the stack to catch up with
-                // the top card.
-                float partiallyThere = (newStackHeight - mTopPadding - mTopPaddingOverflow)
-                        / minStackHeight;
-                partiallyThere = Math.max(0, partiallyThere);
-                translationY += (1 - partiallyThere) * (mBottomStackPeekSize +
-                        mCollapseSecondCardPadding);
-            } else {
-                translationY = (int) (height - normalUnfoldPositionStart);
-            }
+            translationY = newStackHeight - normalUnfoldPositionStart;
             paddingOffset = translationY - mTopPadding;
             stackHeight = (int) (height - (translationY - mTopPadding));
         }
@@ -668,8 +644,8 @@ public class NotificationStackScrollLayout extends ViewGroup
         return mBottomStackPeekSize;
     }
 
-    public int getCollapseSecondCardPadding() {
-        return mCollapseSecondCardPadding;
+    public int getBottomStackSlowDownHeight() {
+        return mBottomStackSlowDownHeight;
     }
 
     public void setLongPressListener(SwipeHelper.LongPressListener listener) {
@@ -1850,7 +1826,7 @@ public class NotificationStackScrollLayout extends ViewGroup
             boolean ignoreIntrinsicPadding) {
         float start = qsHeight;
         float stackHeight = getHeight() - start;
-        int minStackHeight = getMinStackHeight();
+        int minStackHeight = getLayoutMinHeight();
         if (stackHeight <= minStackHeight) {
             float overflow = minStackHeight - stackHeight;
             stackHeight = minStackHeight;
@@ -1864,11 +1840,16 @@ public class NotificationStackScrollLayout extends ViewGroup
         setStackHeight(mLastSetStackHeight);
     }
 
-    public int getMinStackHeight() {
+    public int getLayoutMinHeight() {
         final ExpandableView firstChild = getFirstChildNotGone();
-        final int firstChildMinHeight = firstChild != null ? firstChild.getMinHeight()
+        int firstChildMinHeight = firstChild != null
+                ? firstChild.getIntrinsicHeight()
                 : mCollapsedSize;
-        return firstChildMinHeight + mBottomStackPeekSize + mCollapseSecondCardPadding;
+        if (mOwnScrollY > 0) {
+            firstChildMinHeight = Math.max(firstChildMinHeight - mOwnScrollY, mCollapsedSize);
+        }
+        return Math.min(firstChildMinHeight + mBottomStackPeekSize + mBottomStackSlowDownHeight,
+                mMaxLayoutHeight - mTopPadding);
     }
 
     public float getTopPaddingOverflow() {
@@ -1880,7 +1861,7 @@ public class NotificationStackScrollLayout extends ViewGroup
         final int firstChildMinHeight = firstChild != null ? (int) firstChild.getMinHeight()
                 : mCollapsedSize;
         return mIntrinsicPadding + firstChildMinHeight + mBottomStackPeekSize
-                + mCollapseSecondCardPadding;
+                + mBottomStackSlowDownHeight;
     }
 
     private int clampPadding(int desiredPadding) {
@@ -1994,7 +1975,6 @@ public class NotificationStackScrollLayout extends ViewGroup
     }
 
     private void onViewRemovedInternal(View child) {
-        mStackScrollAlgorithm.notifyChildrenChanged(this);
         if (mChangePositionInProgress) {
             // This is only a position change, don't do anything special
             return;
@@ -2175,7 +2155,6 @@ public class NotificationStackScrollLayout extends ViewGroup
 
     private void onViewAddedInternal(View child) {
         updateHideSensitiveForChild(child);
-        mStackScrollAlgorithm.notifyChildrenChanged(this);
         ((ExpandableView) child).setOnHeightChangedListener(this);
         generateAddAnimation(child, false /* fromMoreCard */);
         updateAnimationState(child);
@@ -2643,12 +2622,8 @@ public class NotificationStackScrollLayout extends ViewGroup
     }
 
     public int getEmptyBottomMargin() {
-        int emptyMargin = mMaxLayoutHeight - mContentHeight - mBottomStackPeekSize;
-        if (needsHeightAdaption()) {
-            emptyMargin -= mBottomStackSlowDownHeight;
-        } else {
-            emptyMargin -= mCollapseSecondCardPadding;
-        }
+        int emptyMargin = mMaxLayoutHeight - mContentHeight - mBottomStackPeekSize
+                - mBottomStackSlowDownHeight;
         return Math.max(emptyMargin, 0);
     }
 
@@ -2659,12 +2634,10 @@ public class NotificationStackScrollLayout extends ViewGroup
 
     public void onExpansionStarted() {
         mIsExpansionChanging = true;
-        mStackScrollAlgorithm.onExpansionStarted(mCurrentStackScrollState);
     }
 
     public void onExpansionStopped() {
         mIsExpansionChanging = false;
-        mStackScrollAlgorithm.onExpansionStopped();
         if (!mIsExpanded) {
             mOwnScrollY = 0;
 
@@ -2732,7 +2705,6 @@ public class NotificationStackScrollLayout extends ViewGroup
         if (mIsExpanded && mAnimationsEnabled) {
             mRequestViewResizeAnimationOnLayout = true;
         }
-        mStackScrollAlgorithm.onReset(view);
         updateAnimationState(view);
         updateChronometerForChild(view);
     }
@@ -3163,15 +3135,7 @@ public class NotificationStackScrollLayout extends ViewGroup
     }
 
     public int getDismissViewHeight() {
-        int height = mDismissView.getHeight() + mPaddingBetweenElements;
-
-        // Hack: Accommodate for additional distance when we only have one notification and the
-        // dismiss all button.
-        if (getNotGoneChildCount() == 2 && getLastChildNotGone() == mDismissView
-                && getFirstChildNotGone() instanceof ActivatableNotificationView) {
-            height += mCollapseSecondCardPadding;
-        }
-        return height;
+        return mDismissView.getHeight() + mPaddingBetweenElements;
     }
 
     public int getEmptyShadeViewHeight() {
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/stack/StackScrollAlgorithm.java b/packages/SystemUI/src/com/android/systemui/statusbar/stack/StackScrollAlgorithm.java
index eea923f68b20..4c94fe93cbdc 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/stack/StackScrollAlgorithm.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/stack/StackScrollAlgorithm.java
@@ -52,13 +52,8 @@ public class StackScrollAlgorithm {
     private StackIndentationFunctor mBottomStackIndentationFunctor;
 
     private StackScrollAlgorithmState mTempAlgorithmState = new StackScrollAlgorithmState();
-    private boolean mIsExpansionChanging;
-    private int mFirstChildMaxHeight;
     private boolean mIsExpanded;
-    private ExpandableView mFirstChildWhileExpanding;
-    private boolean mExpandedOnStart;
     private int mBottomStackSlowDownLength;
-    private int mCollapseSecondCardPadding;
 
     public StackScrollAlgorithm(Context context) {
         initView(context);
@@ -86,8 +81,6 @@ public class StackScrollAlgorithm {
         mZBasicHeight = (MAX_ITEMS_IN_BOTTOM_STACK + 1) * mZDistanceBetweenElements;
         mBottomStackSlowDownLength = context.getResources()
                 .getDimensionPixelSize(R.dimen.bottom_stack_slow_down_length);
-        mCollapseSecondCardPadding = context.getResources().getDimensionPixelSize(
-                R.dimen.notification_collapse_second_card_padding);
         mBottomStackIndentationFunctor = new PiecewiseLinearIndentationFunctor(
                 MAX_ITEMS_IN_BOTTOM_STACK,
                 mBottomStackPeekSize,
@@ -508,7 +501,7 @@ public class StackScrollAlgorithm {
             int childHeight, int minHeight, AmbientState ambientState) {
 
         int bottomStackStart = ambientState.getInnerHeight()
-                - mBottomStackPeekSize - mCollapseSecondCardPadding;
+                - mBottomStackPeekSize - mBottomStackSlowDownLength;
         int childStart = bottomStackStart - childHeight;
         if (childStart < childViewState.yTranslation) {
             float newHeight = bottomStackStart - childViewState.yTranslation;
@@ -595,12 +588,9 @@ public class StackScrollAlgorithm {
 
             // The starting position of the bottom stack peek
             int bottomPeekStart = ambientState.getInnerHeight() - mBottomStackPeekSize -
-                    mCollapseSecondCardPadding + ambientState.getScrollY();
+                    mBottomStackSlowDownLength + ambientState.getScrollY();
             // Collapse and expand the first child while the shade is being expanded
-            float maxHeight = mIsExpansionChanging && child == mFirstChildWhileExpanding
-                    ? mFirstChildMaxHeight
-                    : childHeight;
-            childViewState.height = (int) Math.max(Math.min(bottomPeekStart, maxHeight),
+        childViewState.height = (int) Math.max(Math.min(bottomPeekStart, (float) childHeight),
                     child.getMinHeight());
     }
 
@@ -656,55 +646,6 @@ public class StackScrollAlgorithm {
         }
     }
 
-    public void onExpansionStarted(StackScrollState currentState) {
-        mIsExpansionChanging = true;
-        mExpandedOnStart = mIsExpanded;
-        ViewGroup hostView = currentState.getHostView();
-        updateFirstChildHeightWhileExpanding(hostView);
-    }
-
-    private void updateFirstChildHeightWhileExpanding(ViewGroup hostView) {
-        mFirstChildWhileExpanding = (ExpandableView) findFirstVisibleChild(hostView);
-        if (mFirstChildWhileExpanding != null) {
-            if (mExpandedOnStart) {
-
-                // We are collapsing the shade, so the first child can get as most as high as the
-                // current height or the end value of the animation.
-                mFirstChildMaxHeight = StackStateAnimator.getFinalActualHeight(
-                        mFirstChildWhileExpanding);
-            } else {
-                updateFirstChildMaxSizeToMaxHeight();
-            }
-        } else {
-            mFirstChildMaxHeight = 0;
-        }
-    }
-
-    private void updateFirstChildMaxSizeToMaxHeight() {
-        // We are expanding the shade, expand it to its full height.
-        if (!isMaxSizeInitialized(mFirstChildWhileExpanding)) {
-
-            // This child was not layouted yet, wait for a layout pass
-            mFirstChildWhileExpanding
-                    .addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
-                        @Override
-                        public void onLayoutChange(View v, int left, int top, int right,
-                                int bottom, int oldLeft, int oldTop, int oldRight,
-                                int oldBottom) {
-                            if (mFirstChildWhileExpanding != null) {
-                                mFirstChildMaxHeight = getMaxAllowedChildHeight(
-                                        mFirstChildWhileExpanding);
-                            } else {
-                                mFirstChildMaxHeight = 0;
-                            }
-                            v.removeOnLayoutChangeListener(this);
-                        }
-                    });
-        } else {
-            mFirstChildMaxHeight = getMaxAllowedChildHeight(mFirstChildWhileExpanding);
-        }
-    }
-
     private boolean isMaxSizeInitialized(ExpandableView child) {
         if (child instanceof ExpandableNotificationRow) {
             ExpandableNotificationRow row = (ExpandableNotificationRow) child;
@@ -724,32 +665,10 @@ public class StackScrollAlgorithm {
         return null;
     }
 
-    public void onExpansionStopped() {
-        mIsExpansionChanging = false;
-        mFirstChildWhileExpanding = null;
-    }
-
     public void setIsExpanded(boolean isExpanded) {
         this.mIsExpanded = isExpanded;
     }
 
-    public void notifyChildrenChanged(final NotificationStackScrollLayout hostView) {
-        if (mIsExpansionChanging) {
-            hostView.post(new Runnable() {
-                @Override
-                public void run() {
-                    updateFirstChildHeightWhileExpanding(hostView);
-                }
-            });
-        }
-    }
-
-    public void onReset(ExpandableView view) {
-        if (view.equals(mFirstChildWhileExpanding)) {
-            updateFirstChildMaxSizeToMaxHeight();
-        }
-    }
-
     class StackScrollAlgorithmState {
 
         /**