Merge "Add rotation support to grid-based global actions menu."

9 files changed, 280 insertions, 53 deletions

diff --git a/packages/SystemUI/res/layout-land/global_actions_grid.xml b/packages/SystemUI/res/layout-land/global_actions_grid.xml
new file mode 100644
index 000000000000..911b661d48eb
--- /dev/null
+++ b/packages/SystemUI/res/layout-land/global_actions_grid.xml
@@ -0,0 +1,80 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.android.systemui.globalactions.GlobalActionsGridLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@id/global_actions_view"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="horizontal"
+    android:clipToPadding="false"
+    android:theme="@style/qs_theme"
+    android:gravity="top|right"
+    android:clipChildren="false"
+>
+
+    <LinearLayout
+        android:layout_height="match_parent"
+        android:layout_width="wrap_content"
+        android:gravity="top|right"
+        android:padding="0dp"
+        android:orientation="vertical"
+        android:layoutDirection="ltr"
+        android:layout_marginRight="@dimen/global_actions_grid_container_bottom_margin"
+    >
+        <!-- Grid of action items -->
+        <com.android.systemui.globalactions.ListGridLayout
+            android:id="@android:id/list"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:layoutDirection="ltr"
+            android:layout_marginTop="@dimen/global_actions_grid_side_margin"
+            android:translationZ="@dimen/global_actions_translate"
+            android:paddingLeft="@dimen/global_actions_grid_top_padding"
+            android:paddingRight="@dimen/global_actions_grid_bottom_padding"
+            android:paddingTop="@dimen/global_actions_grid_left_padding"
+            android:paddingBottom="@dimen/global_actions_grid_right_padding"
+            android:background="?android:attr/colorBackgroundFloating"
+        >
+            <LinearLayout
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:visibility="gone"
+                android:layoutDirection="ltr"
+                android:orientation="horizontal"
+            />
+            <LinearLayout
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:visibility="gone"
+                android:layoutDirection="ltr"
+                android:orientation="horizontal"
+            />
+            <LinearLayout
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:visibility="gone"
+                android:layoutDirection="ltr"
+                android:orientation="horizontal"
+            />
+        </com.android.systemui.globalactions.ListGridLayout>
+
+        <!-- For separated items-->
+        <LinearLayout
+            android:id="@+id/separated_button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/global_actions_grid_side_margin"
+            android:layout_marginBottom="@dimen/global_actions_grid_side_margin"
+            android:paddingTop="@dimen/global_actions_grid_left_padding"
+            android:paddingLeft="@dimen/global_actions_grid_top_padding"
+            android:paddingBottom="@dimen/global_actions_grid_right_padding"
+            android:paddingRight="@dimen/global_actions_grid_bottom_padding"
+            android:orientation="horizontal"
+            android:layoutDirection="ltr"
+            android:background="?android:attr/colorBackgroundFloating"
+            android:translationZ="@dimen/global_actions_translate"
+        />
+
+    </LinearLayout>
+
+</com.android.systemui.globalactions.GlobalActionsGridLayout>
diff --git a/packages/SystemUI/res/layout-land/global_actions_grid_seascape.xml b/packages/SystemUI/res/layout-land/global_actions_grid_seascape.xml
new file mode 100644
index 000000000000..669be1b40567
--- /dev/null
+++ b/packages/SystemUI/res/layout-land/global_actions_grid_seascape.xml
@@ -0,0 +1,82 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.android.systemui.globalactions.GlobalActionsGridLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@id/global_actions_view"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="horizontal"
+    android:clipToPadding="false"
+    android:theme="@style/qs_theme"
+    android:gravity="top|left"
+    android:clipChildren="false"
+>
+
+    <LinearLayout
+        android:layout_height="match_parent"
+        android:layout_width="wrap_content"
+        android:gravity="bottom|left"
+        android:padding="0dp"
+        android:orientation="vertical"
+        android:layout_marginLeft="@dimen/global_actions_grid_container_bottom_margin"
+    >
+        <!-- For separated items-->
+        <LinearLayout
+            android:id="@+id/separated_button"
+            android:layout_gravity="top|left"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/global_actions_grid_side_margin"
+            android:layout_marginBottom="@dimen/global_actions_grid_side_margin"
+            android:paddingTop="@dimen/global_actions_grid_left_padding"
+            android:paddingLeft="@dimen/global_actions_grid_top_padding"
+            android:paddingBottom="@dimen/global_actions_grid_right_padding"
+            android:paddingRight="@dimen/global_actions_grid_bottom_padding"
+            android:orientation="horizontal"
+            android:layoutDirection="rtl"
+            android:background="?android:attr/colorBackgroundFloating"
+            android:translationZ="@dimen/global_actions_translate"
+        />
+
+        <!-- Grid of action items -->
+        <com.android.systemui.globalactions.ListGridLayout
+            android:id="@android:id/list"
+            android:layout_gravity="bottom|left"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:layout_marginTop="@dimen/global_actions_grid_side_margin"
+            android:translationZ="@dimen/global_actions_translate"
+            android:paddingLeft="@dimen/global_actions_grid_top_padding"
+            android:paddingRight="@dimen/global_actions_grid_bottom_padding"
+            android:paddingTop="@dimen/global_actions_grid_left_padding"
+            android:paddingBottom="@dimen/global_actions_grid_right_padding"
+            android:background="?android:attr/colorBackgroundFloating"
+        >
+            <LinearLayout
+                android:layout_gravity="bottom"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:visibility="gone"
+                android:layoutDirection="rtl"
+                android:orientation="horizontal"
+            />
+            <LinearLayout
+                android:layout_gravity="bottom"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:visibility="gone"
+                android:layoutDirection="rtl"
+                android:orientation="horizontal"
+            />
+            <LinearLayout
+                android:layout_gravity="bottom"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:visibility="gone"
+                android:layoutDirection="rtl"
+                android:orientation="horizontal"
+            />
+        </com.android.systemui.globalactions.ListGridLayout>
+    </LinearLayout>
+
+</com.android.systemui.globalactions.GlobalActionsGridLayout>
diff --git a/packages/SystemUI/res/layout/global_actions_grid.xml b/packages/SystemUI/res/layout/global_actions_grid.xml
index e6f2376ae76b..1b56fa089281 100644
--- a/packages/SystemUI/res/layout/global_actions_grid.xml
+++ b/packages/SystemUI/res/layout/global_actions_grid.xml
@@ -12,10 +12,11 @@
 >
 
     <LinearLayout
-        android:layout_height="290dp"
-        android:layout_width="412dp"
-        android:gravity="bottom"
+        android:layout_height="wrap_content"
+        android:layout_width="match_parent"
+        android:gravity="bottom | right"
         android:padding="0dp"
+        android:layoutDirection="ltr"
         android:layout_marginBottom="@dimen/global_actions_grid_container_bottom_margin"
     >
         <!-- For separated items-->
@@ -34,15 +35,11 @@
             android:translationZ="@dimen/global_actions_translate"
         />
 
-        <Space android:layout_width="match_parent" android:layout_height="2dp"
-               android:layout_weight="1" />
-
         <!-- Grid of action items -->
         <com.android.systemui.globalactions.ListGridLayout
             android:id="@android:id/list"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:gravity="right"
             android:orientation="horizontal"
             android:layoutDirection="rtl"
             android:layout_marginRight="@dimen/global_actions_grid_side_margin"
@@ -56,25 +53,19 @@
             <LinearLayout
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_gravity="bottom|right"
                 android:visibility="gone"
-                android:gravity="bottom"
                 android:orientation="vertical"
             />
             <LinearLayout
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_gravity="bottom|right"
                 android:visibility="gone"
-                android:gravity="bottom"
                 android:orientation="vertical"
             />
             <LinearLayout
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_gravity="bottom|right"
                 android:visibility="gone"
-                android:gravity="bottom"
                 android:orientation="vertical"
             />
         </com.android.systemui.globalactions.ListGridLayout>
diff --git a/packages/SystemUI/res/layout/global_actions_grid_item.xml b/packages/SystemUI/res/layout/global_actions_grid_item.xml
index 0c11cd977256..a8938390690f 100644
--- a/packages/SystemUI/res/layout/global_actions_grid_item.xml
+++ b/packages/SystemUI/res/layout/global_actions_grid_item.xml
@@ -47,6 +47,7 @@
         android:gravity="center"
         android:textSize="12sp"
         android:textAppearance="?android:attr/textAppearanceSmall"
+        android:singleLine="true"
     />
 
     <TextView
@@ -57,5 +58,6 @@
         android:gravity="center"
         android:textColor="?android:attr/textColorTertiary"
         android:textAppearance="?android:attr/textAppearanceSmall"
+        android:singleLine="true"
     />
 </LinearLayout>
diff --git a/packages/SystemUI/src/com/android/systemui/HardwareUiLayout.java b/packages/SystemUI/src/com/android/systemui/HardwareUiLayout.java
index e28aa9d369cb..2a1d066d356e 100644
--- a/packages/SystemUI/src/com/android/systemui/HardwareUiLayout.java
+++ b/packages/SystemUI/src/com/android/systemui/HardwareUiLayout.java
@@ -23,7 +23,6 @@ import android.animation.AnimatorListenerAdapter;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
 import android.content.Context;
-import android.content.res.Configuration;
 import android.provider.Settings;
 import android.util.AttributeSet;
 import android.view.Gravity;
@@ -59,7 +58,6 @@ public class HardwareUiLayout extends MultiListLayout implements Tunable {
     private int mEndPoint;
     private boolean mEdgeBleed;
     private boolean mRoundedDivider;
-    private int mRotation = ROTATION_NONE;
     private boolean mRotatedBackground;
     private boolean mSwapOrientation = true;
 
@@ -89,7 +87,7 @@ public class HardwareUiLayout extends MultiListLayout implements Tunable {
     }
 
     @Override
-    public ViewGroup getParentView(boolean separated, int index) {
+    public ViewGroup getParentView(boolean separated, int index, boolean reverse) {
         if (separated) {
             return getSeparatedView();
         } else {
@@ -174,7 +172,6 @@ public class HardwareUiLayout extends MultiListLayout implements Tunable {
                 mSeparatedView.setBackground(mSeparatedViewBackground);
                 updateEdgeMargin(mEdgeBleed ? 0 : getEdgePadding());
                 mOldHeight = mList.getMeasuredHeight();
-                updateRotation();
             } else {
                 return;
             }
@@ -188,25 +185,13 @@ public class HardwareUiLayout extends MultiListLayout implements Tunable {
         post(() -> updatePosition());
     }
 
-    @Override
-    protected void onConfigurationChanged(Configuration newConfig) {
-        super.onConfigurationChanged(newConfig);
-        updateRotation();
-    }
-
     public void setSwapOrientation(boolean swapOrientation) {
         mSwapOrientation = swapOrientation;
     }
 
-    private void updateRotation() {
-        int rotation = RotationUtils.getRotation(getContext());
-        if (rotation != mRotation) {
-            rotate(mRotation, rotation);
-            mRotation = rotation;
-        }
-    }
-
-    private void rotate(int from, int to) {
+    @Override
+    protected void rotate(int from, int to) {
+        super.rotate(from, to);
         if (from != ROTATION_NONE && to != ROTATION_NONE) {
             // Rather than handling this confusing case, just do 2 rotations.
             rotate(from, ROTATION_NONE);
diff --git a/packages/SystemUI/src/com/android/systemui/MultiListLayout.java b/packages/SystemUI/src/com/android/systemui/MultiListLayout.java
index 85265f458370..00ff518ce212 100644
--- a/packages/SystemUI/src/com/android/systemui/MultiListLayout.java
+++ b/packages/SystemUI/src/com/android/systemui/MultiListLayout.java
@@ -17,11 +17,14 @@
 package com.android.systemui;
 
 import android.content.Context;
+import android.content.res.Configuration;
 import android.util.AttributeSet;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.LinearLayout;
 
+import com.android.systemui.util.leak.RotationUtils;
+
 /**
  * Layout class representing the Global Actions menu which appears when the power button is held.
  */
@@ -32,8 +35,12 @@ public abstract class MultiListLayout extends LinearLayout {
     protected int mExpectedSeparatedItemCount;
     protected int mExpectedListItemCount;
 
+    protected int mRotation;
+    protected RotationListener mRotationListener;
+
     public MultiListLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
+        mRotation = RotationUtils.getRotation(context);
     }
 
     protected abstract ViewGroup getSeparatedView();
@@ -50,10 +57,12 @@ public abstract class MultiListLayout extends LinearLayout {
      * @param separated Whether or not this index refers to a position in the separated or list
      *                  container.
      * @param index The index of the item within the container.
+     * @param reverse If the MultiListLayout contains sub-lists within the list container, reverse
+     *                the order that they are filled.
      * @return The parent ViewGroup which will be used to contain the specified item
      * after it has been added to the layout.
      */
-    public abstract ViewGroup getParentView(boolean separated, int index);
+    public abstract ViewGroup getParentView(boolean separated, int index, boolean reverse);
 
     /**
      * Sets the divided view, which may have a differently-colored background.
@@ -111,6 +120,26 @@ public abstract class MultiListLayout extends LinearLayout {
         setFocusable(true);
     }
 
+    @Override
+    protected void onConfigurationChanged(Configuration newConfig) {
+        super.onConfigurationChanged(newConfig);
+        int newRotation = RotationUtils.getRotation(mContext);
+        if (newRotation != mRotation) {
+            rotate(mRotation, newRotation);
+            mRotation = newRotation;
+        }
+    }
+
+    protected void rotate(int from, int to) {
+        if (mRotationListener != null) {
+            mRotationListener.onRotate(from, to);
+        }
+    }
+
+    public void setRotationListener(RotationListener listener) {
+        mRotationListener = listener;
+    }
+
     /**
      * Retrieve the MultiListLayout associated with the given view.
      */
@@ -121,4 +150,8 @@ public abstract class MultiListLayout extends LinearLayout {
         }
         return null;
     }
+
+    interface RotationListener {
+        void onRotate(int from, int to);
+    }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/globalactions/GlobalActionsDialog.java b/packages/SystemUI/src/com/android/systemui/globalactions/GlobalActionsDialog.java
index f5ac0d39d61f..7c9b2864f7f2 100644
--- a/packages/SystemUI/src/com/android/systemui/globalactions/GlobalActionsDialog.java
+++ b/packages/SystemUI/src/com/android/systemui/globalactions/GlobalActionsDialog.java
@@ -33,6 +33,7 @@ import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.pm.UserInfo;
+import android.content.res.Configuration;
 import android.database.ContentObserver;
 import android.graphics.Point;
 import android.graphics.drawable.Drawable;
@@ -91,6 +92,7 @@ import com.android.systemui.plugins.GlobalActions.GlobalActionsManager;
 import com.android.systemui.statusbar.phone.ScrimController;
 import com.android.systemui.statusbar.policy.ConfigurationController;
 import com.android.systemui.util.EmergencyDialerConstants;
+import com.android.systemui.util.leak.RotationUtils;
 import com.android.systemui.volume.SystemUIInterpolators.LogAccelerateInterpolator;
 
 import java.util.ArrayList;
@@ -159,6 +161,8 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
     private final ScreenshotHelper mScreenshotHelper;
     private final ScreenRecordHelper mScreenRecordHelper;
 
+    private int mLastRotation;
+
     /**
      * @param context everything needs a context :(
      */
@@ -201,6 +205,8 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
         mScreenshotHelper = new ScreenshotHelper(context);
         mScreenRecordHelper = new ScreenRecordHelper(context);
 
+        mLastRotation = RotationUtils.getRotation(mContext);
+
         Dependency.get(ConfigurationController.class).addCallback(this);
     }
 
@@ -426,6 +432,15 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
         mContext.getTheme().applyStyle(mContext.getThemeResId(), true);
     }
 
+    @Override
+    public void onConfigChanged(Configuration newConfig) {
+        int rotation = RotationUtils.getRotation(mContext);
+        if (rotation != mLastRotation) {
+            mDialog.onRotate();
+        }
+        mLastRotation = rotation;
+    }
+
     public void destroy() {
         Dependency.get(ConfigurationController.class).removeCallback(this);
     }
@@ -1091,7 +1106,7 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
         }
 
         protected int getActionLayoutId(Context context) {
-            if (FeatureFlagUtils.isEnabled(context, FeatureFlagUtils.GLOBAL_ACTIONS_GRID_ENABLED)) {
+            if (isGridEnabled(context)) {
                 return com.android.systemui.R.layout.global_actions_grid_item;
             }
             return com.android.systemui.R.layout.global_actions_item;
@@ -1465,7 +1480,7 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
 
         private final Context mContext;
         private final MyAdapter mAdapter;
-        private final MultiListLayout mGlobalActionsLayout;
+        private MultiListLayout mGlobalActionsLayout;
         private final OnClickListener mClickListener;
         private final OnItemLongClickListener mLongClickListener;
         private final GradientDrawable mGradientDrawable;
@@ -1505,8 +1520,13 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
             window.setBackgroundDrawable(mGradientDrawable);
             window.setType(WindowManager.LayoutParams.TYPE_VOLUME_OVERLAY);
 
+            initializeLayout();
 
-            setContentView(getGlobalActionsLayoutId(context));
+            setTitle(R.string.global_actions);
+        }
+
+        private void initializeLayout() {
+            setContentView(getGlobalActionsLayoutId(mContext));
             mGlobalActionsLayout = (MultiListLayout)
                     findViewById(com.android.systemui.R.id.global_actions_view);
             mGlobalActionsLayout.setOutsideTouchListener(view -> dismiss());
@@ -1520,11 +1540,20 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
                     return true;
                 }
             });
-            setTitle(R.string.global_actions);
+        }
+
+        public void onRotate() {
+            if (mShowing && isGridEnabled(mContext)) {
+                initializeLayout();
+                updateList();
+            }
         }
 
         private int getGlobalActionsLayoutId(Context context) {
-            if (FeatureFlagUtils.isEnabled(context, FeatureFlagUtils.GLOBAL_ACTIONS_GRID_ENABLED)) {
+            if (isGridEnabled(context)) {
+                if (RotationUtils.getRotation(context) == RotationUtils.ROTATION_SEASCAPE) {
+                    return com.android.systemui.R.layout.global_actions_grid_seascape;
+                }
                 return com.android.systemui.R.layout.global_actions_grid;
             }
             return com.android.systemui.R.layout.global_actions_wrapped;
@@ -1543,10 +1572,20 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
                 int separatedIndex = separatedActions.indexOf(action);
                 ViewGroup parent;
                 if (separatedIndex != -1) {
-                    parent = mGlobalActionsLayout.getParentView(true, separatedIndex);
+                    parent = mGlobalActionsLayout.getParentView(true, separatedIndex, false);
                 } else {
+                    boolean reverse = false;
+
+                    // If we're using the grid layout and we're in seascape, reverse the order
+                    // of sublists to make sure they render in the correct positions,
+                    // since we can't reverse vertical LinearLayouts through the layout xml.
+
+                    if (isGridEnabled(mContext) && RotationUtils.getRotation(mContext)
+                            == RotationUtils.ROTATION_SEASCAPE) {
+                        reverse = true;
+                    }
                     int listIndex = listActions.indexOf(action);
-                    parent = mGlobalActionsLayout.getParentView(false, listIndex);
+                    parent = mGlobalActionsLayout.getParentView(false, listIndex, reverse);
                 }
                 View v = mAdapter.getView(i, null, parent);
                 final int pos = i;
@@ -1665,4 +1704,11 @@ class GlobalActionsDialog implements DialogInterface.OnDismissListener,
             mKeyguardShowing = keyguardShowing;
         }
     }
+
+    /**
+     * Determines whether or not the Global Actions Dialog should use the newer grid-style layout.
+     */
+    public static boolean isGridEnabled(Context context) {
+        return FeatureFlagUtils.isEnabled(context, FeatureFlagUtils.GLOBAL_ACTIONS_GRID_ENABLED);
+    }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/globalactions/GlobalActionsGridLayout.java b/packages/SystemUI/src/com/android/systemui/globalactions/GlobalActionsGridLayout.java
index 0e49b5f3cd2a..1d042776efc9 100644
--- a/packages/SystemUI/src/com/android/systemui/globalactions/GlobalActionsGridLayout.java
+++ b/packages/SystemUI/src/com/android/systemui/globalactions/GlobalActionsGridLayout.java
@@ -83,11 +83,11 @@ public class GlobalActionsGridLayout extends MultiListLayout {
     }
 
     @Override
-    public ViewGroup getParentView(boolean separated, int index) {
+    public ViewGroup getParentView(boolean separated, int index, boolean reverseOrder) {
         if (separated) {
             return getSeparatedView();
         } else {
-            return getListView().getParentView(index);
+            return getListView().getParentView(index, reverseOrder);
         }
     }
 
diff --git a/packages/SystemUI/src/com/android/systemui/globalactions/ListGridLayout.java b/packages/SystemUI/src/com/android/systemui/globalactions/ListGridLayout.java
index 37755155751f..d5dcd74c7ea8 100644
--- a/packages/SystemUI/src/com/android/systemui/globalactions/ListGridLayout.java
+++ b/packages/SystemUI/src/com/android/systemui/globalactions/ListGridLayout.java
@@ -28,16 +28,13 @@ import android.widget.LinearLayout;
  *
  * * Try to maintain a 'square' grid (equal number of columns and rows) based on the expected item
  *   count.
+ * * Determine the position and parent of any item by its index and the total item count.
  * * Display and hide sub-lists as needed, depending on the expected item count.
- * * Favor bias toward having more rows or columns depending on the orientation of the device
- *   (TODO(123344999): Implement this, currently always favors adding more rows.)
- * * Change the orientation (horizontal vs. vertical) of the container and sub-lists to act as rows
- *   or columns depending on the orientation of the device.
- *   (TODO(123344999): Implement this, currently always columns.)
  *
  * While we could implement this behavior with a GridLayout, it would take significantly more
  * time and effort, and would require more substantial refactoring of the existing code in
- * GlobalActionsDialog, since it would require manipulation of the child items themselves.
+ * GlobalActionsDialog, since it would require manipulation of layout properties on the child items
+ * themselves.
  *
  */
 
@@ -65,14 +62,25 @@ public class ListGridLayout extends LinearLayout {
     /**
      * Get the parent view associated with the item which should be placed at the given position.
      */
-    public ViewGroup getParentView(int index) {
-        ViewGroup firstParent = (ViewGroup) getChildAt(0);
+    public ViewGroup getParentView(int index, boolean reverseSublists) {
         if (mRows == 0) {
-            return firstParent;
+            return null;
         }
+        int column = getParentViewIndex(index, reverseSublists);
+        return (ViewGroup) getChildAt(column);
+    }
+
+    private int reverseSublistIndex(int index) {
+        return getChildCount() - (index + 1);
+    }
+
+    private int getParentViewIndex(int index, boolean reverseSublists) {
         int column = (int) Math.floor(index / mRows);
-        ViewGroup parent = (ViewGroup) getChildAt(column);
-        return parent != null ? parent : firstParent;
+        int columnCount = getChildCount();
+        if (reverseSublists) {
+            column = reverseSublistIndex(column);
+        }
+        return column;
     }
 
     /**