Fix unused resource check to handle @string references in arrays

This fixes 22850: lint incorrectly reports resources as unused.

Change-Id: I4dc2e82319fcda8c59754911a67f871d5aa00fbc

3 files changed, 23 insertions, 2 deletions

diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/UnusedResourceDetector.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/UnusedResourceDetector.java
index 94ee772..5f2167d 100644
--- a/lint/libs/lint_checks/src/com/android/tools/lint/checks/UnusedResourceDetector.java
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/UnusedResourceDetector.java
@@ -24,8 +24,10 @@ import static com.android.tools.lint.detector.api.LintConstants.RESOURCE_CLR_STY
 import static com.android.tools.lint.detector.api.LintConstants.RESOURCE_CLZ_ARRAY;
 import static com.android.tools.lint.detector.api.LintConstants.RESOURCE_CLZ_ATTR;
 import static com.android.tools.lint.detector.api.LintConstants.RESOURCE_CLZ_ID;
+import static com.android.tools.lint.detector.api.LintConstants.TAG_ARRAY;
 import static com.android.tools.lint.detector.api.LintConstants.TAG_ITEM;
 import static com.android.tools.lint.detector.api.LintConstants.TAG_RESOURCES;
+import static com.android.tools.lint.detector.api.LintConstants.TAG_STRING_ARRAY;
 import static com.android.tools.lint.detector.api.LintConstants.TAG_STYLE;
 
 import com.android.resources.ResourceType;
@@ -420,7 +422,9 @@ public class UnusedResourceDetector extends ResourceXmlDetector implements Detec
     public Collection<String> getApplicableElements() {
         return Arrays.asList(
                 TAG_STYLE,
-                TAG_RESOURCES
+                TAG_RESOURCES,
+                TAG_ARRAY,
+                TAG_STRING_ARRAY
         );
     }
 
@@ -450,7 +454,9 @@ public class UnusedResourceDetector extends ResourceXmlDetector implements Detec
                 }
             }
         } else {
-            assert TAG_STYLE.equals(element.getTagName());
+            assert TAG_STYLE.equals(element.getTagName())
+                || TAG_ARRAY.equals(element.getTagName())
+                || TAG_STRING_ARRAY.equals(element.getTagName());
             // Look for ?attr/ and @dimen/foo etc references in the item children
             for (Element item : LintUtils.getChildren(element)) {
                 NodeList childNodes = item.getChildNodes();
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/UnusedResourceDetectorTest.java b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/UnusedResourceDetectorTest.java
index 96590ba..7213c5d 100644
--- a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/UnusedResourceDetectorTest.java
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/UnusedResourceDetectorTest.java
@@ -80,4 +80,13 @@ public class UnusedResourceDetectorTest extends AbstractCheckTest {
                 "AndroidManifest.xml",
                 "res/layout/accessibility.xml"));
     }
+
+    public void testArrayReference() throws Exception {
+        assertEquals(
+           "arrayusage.xml:3: Warning: The resource R.array.my_array appears to be unused",
+
+            lintProject(
+                "AndroidManifest.xml",
+                "res/values/arrayusage.xml"));
+    }
 }
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/values/arrayusage.xml b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/values/arrayusage.xml
new file mode 100644
index 0000000..0b890f7
--- /dev/null
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/values/arrayusage.xml
@@ -0,0 +1,6 @@
+<resources>
+<string name="my_item">An Item</string>
+<string-array name="my_array">
+   <item>@string/my_item</item>
+</string-array>
+</resources>