Fix support for @empty in style resolution

If @empty is encountered in XML, do not fallback
to searching through the theme.

Bug: 36891052
Test: make aapt2_tests
Test: bit CtsContentTestCases:android.content.res.cts.TypedArrayTest
Change-Id: Ie3bf7b70af9c7913513a1092afd95d26bec5e635

10 files changed, 111 insertions, 89 deletions

diff --git a/core/java/android/content/res/TypedArray.java b/core/java/android/content/res/TypedArray.java
index 0b0f048196a5..f33c75168a5f 100644
--- a/core/java/android/content/res/TypedArray.java
+++ b/core/java/android/content/res/TypedArray.java
@@ -103,7 +103,8 @@ public class TypedArray {
     }
 
     /**
-     * Return the number of indices in the array that actually have data.
+     * Returns the number of indices in the array that actually have data. Attributes with a value
+     * of @empty are included, as this is an explicit indicator.
      *
      * @throws RuntimeException if the TypedArray has already been recycled.
      */
@@ -116,7 +117,8 @@ public class TypedArray {
     }
 
     /**
-     * Returns an index in the array that has data.
+     * Returns an index in the array that has data. Attributes with a value of @empty are included,
+     * as this is an explicit indicator.
      *
      * @param at The index you would like to returned, ranging from 0 to
      *           {@link #getIndexCount()}.
@@ -1017,7 +1019,7 @@ public class TypedArray {
      * @param outValue TypedValue object in which to place the attribute's
      *                 data.
      *
-     * @return {@code true} if the value was retrieved, false otherwise.
+     * @return {@code true} if the value was retrieved and not @empty, {@code false} otherwise.
      * @throws RuntimeException if the TypedArray has already been recycled.
      */
     public boolean getValue(@StyleableRes int index, TypedValue outValue) {
diff --git a/libs/androidfw/AttributeResolution.cpp b/libs/androidfw/AttributeResolution.cpp
index 2771ade1dd12..60e3845d98a9 100644
--- a/libs/androidfw/AttributeResolution.cpp
+++ b/libs/androidfw/AttributeResolution.cpp
@@ -44,8 +44,7 @@ class XmlAttributeFinder
 };
 
 class BagAttributeFinder
-    : public BackTrackingAttributeFinder<BagAttributeFinder,
-                                         const ResTable::bag_entry*> {
+    : public BackTrackingAttributeFinder<BagAttributeFinder, const ResTable::bag_entry*> {
  public:
   BagAttributeFinder(const ResTable::bag_entry* start,
                      const ResTable::bag_entry* end)
@@ -76,8 +75,7 @@ bool ResolveAttrs(ResTable::Theme* theme, uint32_t def_style_attr,
   uint32_t def_style_bag_type_set_flags = 0;
   if (def_style_attr != 0) {
     Res_value value;
-    if (theme->getAttribute(def_style_attr, &value,
-                            &def_style_bag_type_set_flags) >= 0) {
+    if (theme->getAttribute(def_style_attr, &value, &def_style_bag_type_set_flags) >= 0) {
       if (value.dataType == Res_value::TYPE_REFERENCE) {
         def_style_res = value.data;
       }
@@ -127,18 +125,14 @@ bool ResolveAttrs(ResTable::Theme* theme, uint32_t def_style_attr,
         ALOGI("-> From values: type=0x%x, data=0x%08x", value.dataType,
               value.data);
       }
-    }
-
-    if (value.dataType == Res_value::TYPE_NULL) {
-      const ResTable::bag_entry* const def_style_entry =
-          def_style_attr_finder.Find(cur_ident);
+    } else {
+      const ResTable::bag_entry* const def_style_entry = def_style_attr_finder.Find(cur_ident);
       if (def_style_entry != def_style_end) {
         block = def_style_entry->stringBlock;
         type_set_flags = def_style_type_set_flags;
         value = def_style_entry->map.value;
         if (kDebugStyles) {
-          ALOGI("-> From def style: type=0x%x, data=0x%08x", value.dataType,
-                value.data);
+          ALOGI("-> From def style: type=0x%x, data=0x%08x", value.dataType, value.data);
         }
       }
     }
@@ -146,29 +140,24 @@ bool ResolveAttrs(ResTable::Theme* theme, uint32_t def_style_attr,
     uint32_t resid = 0;
     if (value.dataType != Res_value::TYPE_NULL) {
       // Take care of resolving the found resource to its final value.
-      ssize_t new_block = theme->resolveAttributeReference(
-          &value, block, &resid, &type_set_flags, &config);
+      ssize_t new_block =
+          theme->resolveAttributeReference(&value, block, &resid, &type_set_flags, &config);
       if (new_block >= 0) block = new_block;
       if (kDebugStyles) {
-        ALOGI("-> Resolved attr: type=0x%x, data=0x%08x", value.dataType,
-              value.data);
+        ALOGI("-> Resolved attr: type=0x%x, data=0x%08x", value.dataType, value.data);
       }
-    } else {
+    } else if (value.data != Res_value::DATA_NULL_EMPTY) {
       // If we still don't have a value for this attribute, try to find
       // it in the theme!
-      ssize_t new_block =
-          theme->getAttribute(cur_ident, &value, &type_set_flags);
+      ssize_t new_block = theme->getAttribute(cur_ident, &value, &type_set_flags);
       if (new_block >= 0) {
         if (kDebugStyles) {
-          ALOGI("-> From theme: type=0x%x, data=0x%08x", value.dataType,
-                value.data);
+          ALOGI("-> From theme: type=0x%x, data=0x%08x", value.dataType, value.data);
         }
-        new_block = res.resolveReference(&value, new_block, &resid,
-                                         &type_set_flags, &config);
+        new_block = res.resolveReference(&value, new_block, &resid, &type_set_flags, &config);
         if (new_block >= 0) block = new_block;
         if (kDebugStyles) {
-          ALOGI("-> Resolved theme: type=0x%x, data=0x%08x", value.dataType,
-                value.data);
+          ALOGI("-> Resolved theme: type=0x%x, data=0x%08x", value.dataType, value.data);
         }
       }
     }
@@ -184,8 +173,7 @@ bool ResolveAttrs(ResTable::Theme* theme, uint32_t def_style_attr,
     }
 
     if (kDebugStyles) {
-      ALOGI("Attribute 0x%08x: type=0x%x, data=0x%08x", cur_ident,
-            value.dataType, value.data);
+      ALOGI("Attribute 0x%08x: type=0x%x, data=0x%08x", cur_ident, value.dataType, value.data);
     }
 
     // Write the final value back to Java.
@@ -198,7 +186,8 @@ bool ResolveAttrs(ResTable::Theme* theme, uint32_t def_style_attr,
     out_values[STYLE_CHANGING_CONFIGURATIONS] = type_set_flags;
     out_values[STYLE_DENSITY] = config.density;
 
-    if (out_indices != nullptr && value.dataType != Res_value::TYPE_NULL) {
+    if (out_indices != nullptr &&
+        (value.dataType != Res_value::TYPE_NULL || value.data == Res_value::DATA_NULL_EMPTY)) {
       indices_idx++;
       out_indices[indices_idx] = ii;
     }
@@ -247,8 +236,7 @@ void ApplyStyle(ResTable::Theme* theme, ResXMLParser* xml_parser, uint32_t def_s
     ssize_t idx = xml_parser->indexOfStyle();
     if (idx >= 0 && xml_parser->getAttributeValue(idx, &value) >= 0) {
       if (value.dataType == value.TYPE_ATTRIBUTE) {
-        if (theme->getAttribute(value.data, &value, &style_bag_type_set_flags) <
-            0) {
+        if (theme->getAttribute(value.data, &value, &style_bag_type_set_flags) < 0) {
           value.dataType = Res_value::TYPE_NULL;
         }
       }
@@ -318,41 +306,34 @@ void ApplyStyle(ResTable::Theme* theme, ResXMLParser* xml_parser, uint32_t def_s
       // We found the attribute we were looking for.
       xml_parser->getAttributeValue(xml_attr_idx, &value);
       if (kDebugStyles) {
-        ALOGI("-> From XML: type=0x%x, data=0x%08x", value.dataType,
-              value.data);
+        ALOGI("-> From XML: type=0x%x, data=0x%08x", value.dataType, value.data);
       }
     }
 
-    if (value.dataType == Res_value::TYPE_NULL) {
-      // Walk through the style class values looking for the requested
-      // attribute.
-      const ResTable::bag_entry* const style_attr_entry =
-          style_attr_finder.Find(cur_ident);
+    if (value.dataType == Res_value::TYPE_NULL && value.data != Res_value::DATA_NULL_EMPTY) {
+      // Walk through the style class values looking for the requested attribute.
+      const ResTable::bag_entry* const style_attr_entry = style_attr_finder.Find(cur_ident);
       if (style_attr_entry != style_attr_end) {
         // We found the attribute we were looking for.
         block = style_attr_entry->stringBlock;
         type_set_flags = style_type_set_flags;
         value = style_attr_entry->map.value;
         if (kDebugStyles) {
-          ALOGI("-> From style: type=0x%x, data=0x%08x", value.dataType,
-                value.data);
+          ALOGI("-> From style: type=0x%x, data=0x%08x", value.dataType, value.data);
         }
       }
     }
 
-    if (value.dataType == Res_value::TYPE_NULL) {
-      // Walk through the default style values looking for the requested
-      // attribute.
-      const ResTable::bag_entry* const def_style_attr_entry =
-          def_style_attr_finder.Find(cur_ident);
+    if (value.dataType == Res_value::TYPE_NULL && value.data != Res_value::DATA_NULL_EMPTY) {
+      // Walk through the default style values looking for the requested attribute.
+      const ResTable::bag_entry* const def_style_attr_entry = def_style_attr_finder.Find(cur_ident);
       if (def_style_attr_entry != def_style_attr_end) {
         // We found the attribute we were looking for.
         block = def_style_attr_entry->stringBlock;
         type_set_flags = style_type_set_flags;
         value = def_style_attr_entry->map.value;
         if (kDebugStyles) {
-          ALOGI("-> From def style: type=0x%x, data=0x%08x", value.dataType,
-                value.data);
+          ALOGI("-> From def style: type=0x%x, data=0x%08x", value.dataType, value.data);
         }
       }
     }
@@ -360,35 +341,29 @@ void ApplyStyle(ResTable::Theme* theme, ResXMLParser* xml_parser, uint32_t def_s
     uint32_t resid = 0;
     if (value.dataType != Res_value::TYPE_NULL) {
       // Take care of resolving the found resource to its final value.
-      ssize_t new_block = theme->resolveAttributeReference(
-          &value, block, &resid, &type_set_flags, &config);
+      ssize_t new_block =
+          theme->resolveAttributeReference(&value, block, &resid, &type_set_flags, &config);
       if (new_block >= 0) {
         block = new_block;
       }
 
       if (kDebugStyles) {
-        ALOGI("-> Resolved attr: type=0x%x, data=0x%08x", value.dataType,
-              value.data);
+        ALOGI("-> Resolved attr: type=0x%x, data=0x%08x", value.dataType, value.data);
       }
-    } else {
-      // If we still don't have a value for this attribute, try to find
-      // it in the theme!
-      ssize_t new_block =
-          theme->getAttribute(cur_ident, &value, &type_set_flags);
+    } else if (value.data != Res_value::DATA_NULL_EMPTY) {
+      // If we still don't have a value for this attribute, try to find it in the theme!
+      ssize_t new_block = theme->getAttribute(cur_ident, &value, &type_set_flags);
       if (new_block >= 0) {
         if (kDebugStyles) {
-          ALOGI("-> From theme: type=0x%x, data=0x%08x", value.dataType,
-                value.data);
+          ALOGI("-> From theme: type=0x%x, data=0x%08x", value.dataType, value.data);
         }
-        new_block = res.resolveReference(&value, new_block, &resid,
-                                         &type_set_flags, &config);
+        new_block = res.resolveReference(&value, new_block, &resid, &type_set_flags, &config);
         if (new_block >= 0) {
           block = new_block;
         }
 
         if (kDebugStyles) {
-          ALOGI("-> Resolved theme: type=0x%x, data=0x%08x", value.dataType,
-                value.data);
+          ALOGI("-> Resolved theme: type=0x%x, data=0x%08x", value.dataType, value.data);
         }
       }
     }
@@ -404,8 +379,7 @@ void ApplyStyle(ResTable::Theme* theme, ResXMLParser* xml_parser, uint32_t def_s
     }
 
     if (kDebugStyles) {
-      ALOGI("Attribute 0x%08x: type=0x%x, data=0x%08x", cur_ident,
-            value.dataType, value.data);
+      ALOGI("Attribute 0x%08x: type=0x%x, data=0x%08x", cur_ident, value.dataType, value.data);
     }
 
     // Write the final value back to Java.
@@ -418,7 +392,7 @@ void ApplyStyle(ResTable::Theme* theme, ResXMLParser* xml_parser, uint32_t def_s
     out_values[STYLE_CHANGING_CONFIGURATIONS] = type_set_flags;
     out_values[STYLE_DENSITY] = config.density;
 
-    if (value.dataType != Res_value::TYPE_NULL) {
+    if (value.dataType != Res_value::TYPE_NULL || value.data == Res_value::DATA_NULL_EMPTY) {
       indices_idx++;
 
       // out_indices must NOT be nullptr.
@@ -502,7 +476,8 @@ bool RetrieveAttributes(const ResTable* res, ResXMLParser* xml_parser,
     out_values[STYLE_CHANGING_CONFIGURATIONS] = type_set_flags;
     out_values[STYLE_DENSITY] = config.density;
 
-    if (out_indices != nullptr && value.dataType != Res_value::TYPE_NULL) {
+    if (out_indices != nullptr &&
+        (value.dataType != Res_value::TYPE_NULL || value.data == Res_value::DATA_NULL_EMPTY)) {
       indices_idx++;
       out_indices[indices_idx] = ii;
     }
diff --git a/libs/androidfw/ResourceTypes.cpp b/libs/androidfw/ResourceTypes.cpp
index f661f29bb7f9..f526dfb8e190 100644
--- a/libs/androidfw/ResourceTypes.cpp
+++ b/libs/androidfw/ResourceTypes.cpp
@@ -3538,7 +3538,8 @@ status_t ResTable::Theme::applyStyle(uint32_t resID, bool force)
                     attrRes, bag->map.value.dataType, bag->map.value.data,
                     curEntry->value.dataType);
         }
-        if (force || curEntry->value.dataType == Res_value::TYPE_NULL) {
+        if (force || (curEntry->value.dataType == Res_value::TYPE_NULL
+                && curEntry->value.data != Res_value::DATA_NULL_EMPTY)) {
             curEntry->stringBlock = bag->stringBlock;
             curEntry->typeSpecFlags |= bagTypeSpecFlags;
             curEntry->value = bag->map.value;
@@ -3674,7 +3675,8 @@ ssize_t ResTable::Theme::getAttribute(uint32_t resID, Res_value* outValue,
                             }
                             ALOGW("Too many attribute references, stopped at: 0x%08x\n", resID);
                             return BAD_INDEX;
-                        } else if (type != Res_value::TYPE_NULL) {
+                        } else if (type != Res_value::TYPE_NULL
+                                || te.value.data == Res_value::DATA_NULL_EMPTY) {
                             *outValue = te.value;
                             return te.stringBlock;
                         }
diff --git a/libs/androidfw/tests/AssetManager2_test.cpp b/libs/androidfw/tests/AssetManager2_test.cpp
index d8e5abfe8ce9..fcae53b322b3 100644
--- a/libs/androidfw/tests/AssetManager2_test.cpp
+++ b/libs/androidfw/tests/AssetManager2_test.cpp
@@ -264,7 +264,7 @@ TEST_F(AssetManager2Test, MergesStylesWithParentFromSingleApkAssets) {
 
   const ResolvedBag* bag_two = assetmanager.GetBag(app::R::style::StyleTwo);
   ASSERT_NE(nullptr, bag_two);
-  ASSERT_EQ(5u, bag_two->entry_count);
+  ASSERT_EQ(6u, bag_two->entry_count);
 
   // attr_one is inherited from StyleOne.
   EXPECT_EQ(app::R::attr::attr_one, bag_two->entries[0].key);
@@ -295,6 +295,11 @@ TEST_F(AssetManager2Test, MergesStylesWithParentFromSingleApkAssets) {
   EXPECT_EQ(Res_value::TYPE_INT_DEC, bag_two->entries[4].value.dataType);
   EXPECT_EQ(3u, bag_two->entries[4].value.data);
   EXPECT_EQ(0, bag_two->entries[4].cookie);
+
+  EXPECT_EQ(app::R::attr::attr_empty, bag_two->entries[5].key);
+  EXPECT_EQ(Res_value::TYPE_NULL, bag_two->entries[5].value.dataType);
+  EXPECT_EQ(Res_value::DATA_NULL_EMPTY, bag_two->entries[5].value.data);
+  EXPECT_EQ(0, bag_two->entries[5].cookie);
 }
 
 TEST_F(AssetManager2Test, ResolveReferenceToResource) {
diff --git a/libs/androidfw/tests/AttributeResolution_test.cpp b/libs/androidfw/tests/AttributeResolution_test.cpp
index 1ff2ed40cfc4..2d73ce8f8ee3 100644
--- a/libs/androidfw/tests/AttributeResolution_test.cpp
+++ b/libs/androidfw/tests/AttributeResolution_test.cpp
@@ -69,8 +69,8 @@ TEST_F(AttributeResolutionTest, Theme) {
   ResTable::Theme theme(table_);
   ASSERT_EQ(NO_ERROR, theme.applyStyle(R::style::StyleTwo));
 
-  std::array<uint32_t, 4> attrs{
-      {R::attr::attr_one, R::attr::attr_two, R::attr::attr_three, R::attr::attr_four}};
+  std::array<uint32_t, 5> attrs{{R::attr::attr_one, R::attr::attr_two, R::attr::attr_three,
+                                 R::attr::attr_four, R::attr::attr_empty}};
   std::array<uint32_t, attrs.size() * STYLE_NUM_ENTRIES> values;
 
   ASSERT_TRUE(ResolveAttrs(&theme, 0 /*def_style_attr*/, 0 /*def_style_res*/,
@@ -109,11 +109,21 @@ TEST_F(AttributeResolutionTest, Theme) {
   EXPECT_EQ(uint32_t(-1), values_cursor[STYLE_ASSET_COOKIE]);
   EXPECT_EQ(0u, values_cursor[STYLE_DENSITY]);
   EXPECT_EQ(0u, values_cursor[STYLE_CHANGING_CONFIGURATIONS]);
+
+  // @empty comes from the theme, so it has the same asset cookie and changing configurations flags
+  // as the theme.
+  values_cursor += STYLE_NUM_ENTRIES;
+  EXPECT_EQ(Res_value::TYPE_NULL, values_cursor[STYLE_TYPE]);
+  EXPECT_EQ(Res_value::DATA_NULL_EMPTY, values_cursor[STYLE_DATA]);
+  EXPECT_EQ(0u, values_cursor[STYLE_RESOURCE_ID]);
+  EXPECT_EQ(1u, values_cursor[STYLE_ASSET_COOKIE]);
+  EXPECT_EQ(0u, values_cursor[STYLE_DENSITY]);
+  EXPECT_EQ(public_flag, values_cursor[STYLE_CHANGING_CONFIGURATIONS]);
 }
 
 TEST_F(AttributeResolutionXmlTest, XmlParser) {
-  std::array<uint32_t, 4> attrs{
-      {R::attr::attr_one, R::attr::attr_two, R::attr::attr_three, R::attr::attr_four}};
+  std::array<uint32_t, 5> attrs{{R::attr::attr_one, R::attr::attr_two, R::attr::attr_three,
+                                 R::attr::attr_four, R::attr::attr_empty}};
   std::array<uint32_t, attrs.size() * STYLE_NUM_ENTRIES> values;
 
   ASSERT_TRUE(RetrieveAttributes(&table_, &xml_parser_, attrs.data(), attrs.size(), values.data(),
@@ -121,7 +131,7 @@ TEST_F(AttributeResolutionXmlTest, XmlParser) {
 
   uint32_t* values_cursor = values.data();
   EXPECT_EQ(Res_value::TYPE_NULL, values_cursor[STYLE_TYPE]);
-  EXPECT_EQ(0u, values_cursor[STYLE_DATA]);
+  EXPECT_EQ(Res_value::DATA_NULL_EMPTY, values_cursor[STYLE_DATA]);
   EXPECT_EQ(0u, values_cursor[STYLE_RESOURCE_ID]);
   EXPECT_EQ(uint32_t(-1), values_cursor[STYLE_ASSET_COOKIE]);
   EXPECT_EQ(0u, values_cursor[STYLE_DENSITY]);
@@ -150,16 +160,24 @@ TEST_F(AttributeResolutionXmlTest, XmlParser) {
   EXPECT_EQ(uint32_t(-1), values_cursor[STYLE_ASSET_COOKIE]);
   EXPECT_EQ(0u, values_cursor[STYLE_DENSITY]);
   EXPECT_EQ(0u, values_cursor[STYLE_CHANGING_CONFIGURATIONS]);
+
+  values_cursor += STYLE_NUM_ENTRIES;
+  EXPECT_EQ(Res_value::TYPE_NULL, values_cursor[STYLE_TYPE]);
+  EXPECT_EQ(Res_value::DATA_NULL_UNDEFINED, values_cursor[STYLE_DATA]);
+  EXPECT_EQ(0u, values_cursor[STYLE_RESOURCE_ID]);
+  EXPECT_EQ(uint32_t(-1), values_cursor[STYLE_ASSET_COOKIE]);
+  EXPECT_EQ(0u, values_cursor[STYLE_DENSITY]);
+  EXPECT_EQ(0u, values_cursor[STYLE_CHANGING_CONFIGURATIONS]);
 }
 
 TEST_F(AttributeResolutionXmlTest, ThemeAndXmlParser) {
   ResTable::Theme theme(table_);
   ASSERT_EQ(NO_ERROR, theme.applyStyle(R::style::StyleTwo));
 
-  std::array<uint32_t, 5> attrs{{R::attr::attr_one, R::attr::attr_two, R::attr::attr_three,
-                                 R::attr::attr_four, R::attr::attr_five}};
+  std::array<uint32_t, 6> attrs{{R::attr::attr_one, R::attr::attr_two, R::attr::attr_three,
+                                 R::attr::attr_four, R::attr::attr_five, R::attr::attr_empty}};
   std::array<uint32_t, attrs.size() * STYLE_NUM_ENTRIES> values;
-  std::array<uint32_t, attrs.size()> indices;
+  std::array<uint32_t, attrs.size() + 1> indices;
 
   ApplyStyle(&theme, &xml_parser_, 0 /*def_style_attr*/, 0 /*def_style_res*/, attrs.data(),
              attrs.size(), values.data(), indices.data());
@@ -167,12 +185,12 @@ TEST_F(AttributeResolutionXmlTest, ThemeAndXmlParser) {
   const uint32_t public_flag = ResTable_typeSpec::SPEC_PUBLIC;
 
   uint32_t* values_cursor = values.data();
-  EXPECT_EQ(Res_value::TYPE_INT_DEC, values_cursor[STYLE_TYPE]);
-  EXPECT_EQ(1u, values_cursor[STYLE_DATA]);
+  EXPECT_EQ(Res_value::TYPE_NULL, values_cursor[STYLE_TYPE]);
+  EXPECT_EQ(Res_value::DATA_NULL_EMPTY, values_cursor[STYLE_DATA]);
   EXPECT_EQ(0u, values_cursor[STYLE_RESOURCE_ID]);
-  EXPECT_EQ(1u, values_cursor[STYLE_ASSET_COOKIE]);
+  EXPECT_EQ(uint32_t(-1), values_cursor[STYLE_ASSET_COOKIE]);
   EXPECT_EQ(0u, values_cursor[STYLE_DENSITY]);
-  EXPECT_EQ(public_flag, values_cursor[STYLE_CHANGING_CONFIGURATIONS]);
+  EXPECT_EQ(0u, values_cursor[STYLE_CHANGING_CONFIGURATIONS]);
 
   values_cursor += STYLE_NUM_ENTRIES;
   EXPECT_EQ(Res_value::TYPE_STRING, values_cursor[STYLE_TYPE]);
@@ -203,6 +221,20 @@ TEST_F(AttributeResolutionXmlTest, ThemeAndXmlParser) {
   EXPECT_EQ(1u, values_cursor[STYLE_ASSET_COOKIE]);
   EXPECT_EQ(0u, values_cursor[STYLE_DENSITY]);
   EXPECT_EQ(public_flag, values_cursor[STYLE_CHANGING_CONFIGURATIONS]);
+
+  // @empty comes from the theme, so it has the same asset cookie and changing configurations flags
+  // as the theme.
+  values_cursor += STYLE_NUM_ENTRIES;
+  EXPECT_EQ(Res_value::TYPE_NULL, values_cursor[STYLE_TYPE]);
+  EXPECT_EQ(Res_value::DATA_NULL_EMPTY, values_cursor[STYLE_DATA]);
+  EXPECT_EQ(0u, values_cursor[STYLE_RESOURCE_ID]);
+  EXPECT_EQ(1u, values_cursor[STYLE_ASSET_COOKIE]);
+  EXPECT_EQ(0u, values_cursor[STYLE_DENSITY]);
+  EXPECT_EQ(public_flag, values_cursor[STYLE_CHANGING_CONFIGURATIONS]);
+
+  // The first element of indices contains the number of indices.
+  std::array<uint32_t, 7> expected_indices = {{6u, 0u, 1u, 2u, 3u, 4u, 5u}};
+  EXPECT_EQ(expected_indices, indices);
 }
 
 } // namespace android
diff --git a/libs/androidfw/tests/data/styles/R.h b/libs/androidfw/tests/data/styles/R.h
index 68527c744b37..05073a8869ec 100644
--- a/libs/androidfw/tests/data/styles/R.h
+++ b/libs/androidfw/tests/data/styles/R.h
@@ -33,6 +33,7 @@ struct R {
       attr_five = 0x7f010004u,
       attr_indirect = 0x7f010005u,
       attr_six = 0x7f010006u,
+      attr_empty = 0x7f010007u,
     };
   };
 
diff --git a/libs/androidfw/tests/data/styles/build b/libs/androidfw/tests/data/styles/build
index 81f78b1b7b7f..1ef8e6e19208 100755
--- a/libs/androidfw/tests/data/styles/build
+++ b/libs/androidfw/tests/data/styles/build
@@ -2,4 +2,5 @@
 
 set -e
 
-aapt package -F styles.apk -M AndroidManifest.xml -S res -f
+aapt2 compile -o compiled.flata --dir res
+aapt2 link -o styles.apk --manifest AndroidManifest.xml compiled.flata
diff --git a/libs/androidfw/tests/data/styles/res/layout/layout.xml b/libs/androidfw/tests/data/styles/res/layout/layout.xml
index f3aa0f83d9a3..2c5e9476e150 100644
--- a/libs/androidfw/tests/data/styles/res/layout/layout.xml
+++ b/libs/androidfw/tests/data/styles/res/layout/layout.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <View xmlns:app="http://schemas.android.com/apk/res-auto"
     app:attr_four="?attr/attr_indirect"
-    app:attr_three="10" />
-
+    app:attr_three="10"
+    app:attr_one="@empty" />
diff --git a/libs/androidfw/tests/data/styles/res/values/styles.xml b/libs/androidfw/tests/data/styles/res/values/styles.xml
index da592f806d21..3c90317a62c6 100644
--- a/libs/androidfw/tests/data/styles/res/values/styles.xml
+++ b/libs/androidfw/tests/data/styles/res/values/styles.xml
@@ -33,6 +33,12 @@
     <public type="attr" name="attr_indirect" id="0x7f010005" />
     <attr name="attr_indirect" />
 
+    <public type="attr" name="attr_six" id="0x7f010006" />
+    <attr name="attr_six" />
+
+    <public type="attr" name="attr_empty" id="0x7f010007" />
+    <attr name="attr_empty" />
+
     <public type="string" name="string_one" id="0x7f030000" />
     <string name="string_one">Hi</string>
 
@@ -48,11 +54,9 @@
         <item name="attr_two">"string"</item>
         <item name="attr_three">?attr/attr_indirect</item>
         <item name="attr_five">@string/string_one</item>
+        <item name="attr_empty">@empty</item>
     </style>
-    
-    <public type="attr" name="attr_six" id="0x7f010006" />
-    <attr name="attr_six" />
-    
+
     <public type="style" name="StyleThree" id="0x7f020002" />
     <style name="StyleThree">
         <item name="attr_six">6</item>
diff --git a/libs/androidfw/tests/data/styles/styles.apk b/libs/androidfw/tests/data/styles/styles.apk
index d4ccb8391202..72abf8ff2b40 100644
--- a/libs/androidfw/tests/data/styles/styles.apk
+++ b/libs/androidfw/tests/data/styles/styles.apk