null header and footer allowed in HeaderViewListAdapter.

The view infos should never be null since they are created by ListView, which is
the natural and only use of this class.
However, some tests in CTS pass null pointers. Replace null by a static empty list.

http://b/issue?id=2527753

Change-Id: I9b92fa018c89007f12be899285f75130b2c8ac40

1 files changed, 20 insertions, 5 deletions

diff --git a/core/java/android/widget/HeaderViewListAdapter.java b/core/java/android/widget/HeaderViewListAdapter.java
index ca97987..e2a269e 100644
--- a/core/java/android/widget/HeaderViewListAdapter.java
+++ b/core/java/android/widget/HeaderViewListAdapter.java
@@ -31,15 +31,21 @@ import java.util.ArrayList;
  */
 public class HeaderViewListAdapter implements WrapperListAdapter, Filterable {
 
-    private ListAdapter mAdapter;
+    private final ListAdapter mAdapter;
 
     // These two ArrayList are assumed to NOT be null.
-    // They are indeed created when declared in ListView and then shared. 
+    // They are indeed created when declared in ListView and then shared.
     ArrayList<ListView.FixedViewInfo> mHeaderViewInfos;
     ArrayList<ListView.FixedViewInfo> mFooterViewInfos;
+
+    // Used as a placeholder in case the provided info views are indeed null.
+    // Currently only used by some CTS tests, which may be removed.
+    static final ArrayList<ListView.FixedViewInfo> EMPTY_INFO_LIST =
+        new ArrayList<ListView.FixedViewInfo>();
+
     boolean mAreAllFixedViewsSelectable;
 
-    private boolean mIsFilterable;
+    private final boolean mIsFilterable;
 
     public HeaderViewListAdapter(ArrayList<ListView.FixedViewInfo> headerViewInfos,
                                  ArrayList<ListView.FixedViewInfo> footerViewInfos,
@@ -47,8 +53,17 @@ public class HeaderViewListAdapter implements WrapperListAdapter, Filterable {
         mAdapter = adapter;
         mIsFilterable = adapter instanceof Filterable;
 
-        mHeaderViewInfos = headerViewInfos;
-        mFooterViewInfos = footerViewInfos;
+        if (headerViewInfos == null) {
+            mHeaderViewInfos = EMPTY_INFO_LIST;
+        } else {
+            mHeaderViewInfos = headerViewInfos;
+        }
+
+        if (footerViewInfos == null) {
+            mFooterViewInfos = EMPTY_INFO_LIST;
+        } else {
+            mFooterViewInfos = footerViewInfos;
+        }
 
         mAreAllFixedViewsSelectable =
                 areAllListInfosSelectable(mHeaderViewInfos)